contrib/binutils-2.20/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(const General_options& options,
  71                     Symbol_table* symtab,
  72                     Layout* layout,
  73                     Sized_relobj<32, false>* object,
  74                     unsigned int data_shndx,
  75                     unsigned int sh_type,
  76                     const unsigned char* prelocs,
  77                     size_t reloc_count,
  78                     Output_section* output_section,
  79                     bool needs_special_offset_handling,
  80                     size_t local_symbol_count,
  81                     const unsigned char* plocal_symbols);
  82
  83   // Scan the relocations to look for symbol adjustments.
  84   void
  85   scan_relocs(const General_options& options,
  86               Symbol_table* symtab,
  87               Layout* layout,
  88               Sized_relobj<32, false>* object,
  89               unsigned int data_shndx,
  90               unsigned int sh_type,
  91               const unsigned char* prelocs,
  92               size_t reloc_count,
  93               Output_section* output_section,
  94               bool needs_special_offset_handling,
  95               size_t local_symbol_count,
  96               const unsigned char* plocal_symbols);
  97
  98   // Finalize the sections.
  99   void
 100   do_finalize_sections(Layout*);
 101
 102   // Return the value to use for a dynamic which requires special
 103   // treatment.
 104   uint64_t
 105   do_dynsym_value(const Symbol*) const;
 106
 107   // Relocate a section.
 108   void
 109   relocate_section(const Relocate_info<32, false>*,
 110                    unsigned int sh_type,
 111                    const unsigned char* prelocs,
 112                    size_t reloc_count,
 113                    Output_section* output_section,
 114                    bool needs_special_offset_handling,
 115                    unsigned char* view,
 116                    elfcpp::Elf_types<32>::Elf_Addr view_address,
 117                    section_size_type view_size,
 118                    const Reloc_symbol_changes*);
 119
 120   // Scan the relocs during a relocatable link.
 121   void
 122   scan_relocatable_relocs(const General_options& options,
 123                           Symbol_table* symtab,
 124                           Layout* layout,
 125                           Sized_relobj<32, false>* object,
 126                           unsigned int data_shndx,
 127                           unsigned int sh_type,
 128                           const unsigned char* prelocs,
 129                           size_t reloc_count,
 130                           Output_section* output_section,
 131                           bool needs_special_offset_handling,
 132                           size_t local_symbol_count,
 133                           const unsigned char* plocal_symbols,
 134                           Relocatable_relocs*);
 135
 136   // Relocate a section during a relocatable link.
 137   void
 138   relocate_for_relocatable(const Relocate_info<32, false>*,
 139                            unsigned int sh_type,
 140                            const unsigned char* prelocs,
 141                            size_t reloc_count,
 142                            Output_section* output_section,
 143                            off_t offset_in_output_section,
 144                            const Relocatable_relocs*,
 145                            unsigned char* view,
 146                            elfcpp::Elf_types<32>::Elf_Addr view_address,
 147                            section_size_type view_size,
 148                            unsigned char* reloc_view,
 149                            section_size_type reloc_view_size);
 150
 151   // Return a string used to fill a code section with nops.
 152   std::string
 153   do_code_fill(section_size_type length) const;
 154
 155   // Return whether SYM is defined by the ABI.
 156   bool
 157   do_is_defined_by_abi(const Symbol* sym) const
 158   { return strcmp(sym->name(), "___tls_get_addr") == 0; }
 159
 160   // Return whether a symbol name implies a local label.  The UnixWare
 161   // 2.1 cc generates temporary symbols that start with .X, so we
 162   // recognize them here.  FIXME: do other SVR4 compilers also use .X?.
 163   // If so, we should move the .X recognition into
 164   // Target::do_is_local_label_name.
 165   bool
 166   do_is_local_label_name(const char* name) const
 167   {
 168     if (name[0] == '.' && name[1] == 'X')
 169       return true;
 170     return Target::do_is_local_label_name(name);
 171   }
 172
 173   // Adjust -fstack-split code which calls non-stack-split code.
 174   void
 175   do_calls_non_split(Relobj* object, unsigned int shndx,
 176                      section_offset_type fnoffset, section_size_type fnsize,
 177                      unsigned char* view, section_size_type view_size,
 178                      std::string* from, std::string* to) const;
 179
 180   // Return the size of the GOT section.
 181   section_size_type
 182   got_size()
 183   {
 184     gold_assert(this->got_ != NULL);
 185     return this->got_->data_size();
 186   }
 187
 188  private:
 189   // The class which scans relocations.
 190   struct Scan
 191   {
 192     inline void
 193     local(const General_options& options, Symbol_table* symtab,
 194           Layout* layout, Target_i386* target,
 195           Sized_relobj<32, false>* object,
 196           unsigned int data_shndx,
 197           Output_section* output_section,
 198           const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
 199           const elfcpp::Sym<32, false>& lsym);
 200
 201     inline void
 202     global(const General_options& options, Symbol_table* symtab,
 203            Layout* layout, Target_i386* target,
 204            Sized_relobj<32, false>* object,
 205            unsigned int data_shndx,
 206            Output_section* output_section,
 207            const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
 208            Symbol* gsym);
 209
 210     static void
 211     unsupported_reloc_local(Sized_relobj<32, false>*, unsigned int r_type);
 212
 213     static void
 214     unsupported_reloc_global(Sized_relobj<32, false>*, unsigned int r_type,
 215                              Symbol*);
 216   };
 217
 218   // The class which implements relocation.
 219   class Relocate
 220   {
 221    public:
 222     Relocate()
 223       : skip_call_tls_get_addr_(false),
 224         local_dynamic_type_(LOCAL_DYNAMIC_NONE)
 225     { }
 226
 227     ~Relocate()
 228     {
 229       if (this->skip_call_tls_get_addr_)
 230         {
 231           // FIXME: This needs to specify the location somehow.
 232           gold_error(_("missing expected TLS relocation"));
 233         }
 234     }
 235
 236     // Return whether the static relocation needs to be applied.
 237     inline bool
 238     should_apply_static_reloc(const Sized_symbol<32>* gsym,
 239                               int ref_flags,
 240                               bool is_32bit,
 241                               Output_section* output_section);
 242
 243     // Do a relocation.  Return false if the caller should not issue
 244     // any warnings about this relocation.
 245     inline bool
 246     relocate(const Relocate_info<32, false>*, Target_i386*, Output_section*,
 247              size_t relnum, const elfcpp::Rel<32, false>&,
 248              unsigned int r_type, const Sized_symbol<32>*,
 249              const Symbol_value<32>*,
 250              unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
 251              section_size_type);
 252
 253    private:
 254     // Do a TLS relocation.
 255     inline void
 256     relocate_tls(const Relocate_info<32, false>*, Target_i386* target,
 257                  size_t relnum, const elfcpp::Rel<32, false>&,
 258                  unsigned int r_type, const Sized_symbol<32>*,
 259                  const Symbol_value<32>*,
 260                  unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
 261                  section_size_type);
 262
 263     // Do a TLS General-Dynamic to Initial-Exec transition.
 264     inline void
 265     tls_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
 266                  Output_segment* tls_segment,
 267                  const elfcpp::Rel<32, false>&, unsigned int r_type,
 268                  elfcpp::Elf_types<32>::Elf_Addr value,
 269                  unsigned char* view,
 270                  section_size_type view_size);
 271
 272     // Do a TLS General-Dynamic to Local-Exec transition.
 273     inline void
 274     tls_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
 275                  Output_segment* tls_segment,
 276                  const elfcpp::Rel<32, false>&, unsigned int r_type,
 277                  elfcpp::Elf_types<32>::Elf_Addr value,
 278                  unsigned char* view,
 279                  section_size_type view_size);
 280
 281     // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Initial-Exec
 282     // transition.
 283     inline void
 284     tls_desc_gd_to_ie(const Relocate_info<32, false>*, size_t relnum,
 285                       Output_segment* tls_segment,
 286                       const elfcpp::Rel<32, false>&, unsigned int r_type,
 287                       elfcpp::Elf_types<32>::Elf_Addr value,
 288                       unsigned char* view,
 289                       section_size_type view_size);
 290
 291     // Do a TLS_GOTDESC or TLS_DESC_CALL General-Dynamic to Local-Exec
 292     // transition.
 293     inline void
 294     tls_desc_gd_to_le(const Relocate_info<32, false>*, size_t relnum,
 295                       Output_segment* tls_segment,
 296                       const elfcpp::Rel<32, false>&, unsigned int r_type,
 297                       elfcpp::Elf_types<32>::Elf_Addr value,
 298                       unsigned char* view,
 299                       section_size_type view_size);
 300
 301     // Do a TLS Local-Dynamic to Local-Exec transition.
 302     inline void
 303     tls_ld_to_le(const Relocate_info<32, false>*, size_t relnum,
 304                  Output_segment* tls_segment,
 305                  const elfcpp::Rel<32, false>&, unsigned int r_type,
 306                  elfcpp::Elf_types<32>::Elf_Addr value,
 307                  unsigned char* view,
 308                  section_size_type view_size);
 309
 310     // Do a TLS Initial-Exec to Local-Exec transition.
 311     static inline void
 312     tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum,
 313                  Output_segment* tls_segment,
 314                  const elfcpp::Rel<32, false>&, unsigned int r_type,
 315                  elfcpp::Elf_types<32>::Elf_Addr value,
 316                  unsigned char* view,
 317                  section_size_type view_size);
 318
 319     // We need to keep track of which type of local dynamic relocation
 320     // we have seen, so that we can optimize R_386_TLS_LDO_32 correctly.
 321     enum Local_dynamic_type
 322     {
 323       LOCAL_DYNAMIC_NONE,
 324       LOCAL_DYNAMIC_SUN,
 325       LOCAL_DYNAMIC_GNU
 326     };
 327
 328     // This is set if we should skip the next reloc, which should be a
 329     // PLT32 reloc against ___tls_get_addr.
 330     bool skip_call_tls_get_addr_;
 331     // The type of local dynamic relocation we have seen in the section
 332     // being relocated, if any.
 333     Local_dynamic_type local_dynamic_type_;
 334   };
 335
 336   // A class which returns the size required for a relocation type,
 337   // used while scanning relocs during a relocatable link.
 338   class Relocatable_size_for_reloc
 339   {
 340    public:
 341     unsigned int
 342     get_size_for_reloc(unsigned int, Relobj*);
 343   };
 344
 345   // Adjust TLS relocation type based on the options and whether this
 346   // is a local symbol.
 347   static tls::Tls_optimization
 348   optimize_tls_reloc(bool is_final, int r_type);
 349
 350   // Get the GOT section, creating it if necessary.
 351   Output_data_got<32, false>*
 352   got_section(Symbol_table*, Layout*);
 353
 354   // Get the GOT PLT section.
 355   Output_data_space*
 356   got_plt_section() const
 357   {
 358     gold_assert(this->got_plt_ != NULL);
 359     return this->got_plt_;
 360   }
 361
 362   // Create a PLT entry for a global symbol.
 363   void
 364   make_plt_entry(Symbol_table*, Layout*, Symbol*);
 365
 366   // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
 367   void
 368   define_tls_base_symbol(Symbol_table*, Layout*);
 369
 370   // Create a GOT entry for the TLS module index.
 371   unsigned int
 372   got_mod_index_entry(Symbol_table* symtab, Layout* layout,
 373                       Sized_relobj<32, false>* object);
 374
 375   // Get the PLT section.
 376   const Output_data_plt_i386*
 377   plt_section() const
 378   {
 379     gold_assert(this->plt_ != NULL);
 380     return this->plt_;
 381   }
 382
 383   // Get the dynamic reloc section, creating it if necessary.
 384   Reloc_section*
 385   rel_dyn_section(Layout*);
 386
 387   // Add a potential copy relocation.
 388   void
 389   copy_reloc(Symbol_table* symtab, Layout* layout,
 390              Sized_relobj<32, false>* object,
 391              unsigned int shndx, Output_section* output_section,
 392              Symbol* sym, const elfcpp::Rel<32, false>& reloc)
 393   {
 394     this->copy_relocs_.copy_reloc(symtab, layout,
 395                                   symtab->get_sized_symbol<32>(sym),
 396                                   object, shndx, output_section, reloc,
 397                                   this->rel_dyn_section(layout));
 398   }
 399
 400   // Information about this specific target which we pass to the
 401   // general Target structure.
 402   static const Target::Target_info i386_info;
 403
 404   // The types of GOT entries needed for this platform.
 405   enum Got_type
 406   {
 407     GOT_TYPE_STANDARD = 0,      // GOT entry for a regular symbol
 408     GOT_TYPE_TLS_NOFFSET = 1,   // GOT entry for negative TLS offset
 409     GOT_TYPE_TLS_OFFSET = 2,    // GOT entry for positive TLS offset
 410     GOT_TYPE_TLS_PAIR = 3,      // GOT entry for TLS module/offset pair
 411     GOT_TYPE_TLS_DESC = 4       // GOT entry for TLS_DESC pair
 412   };
 413
 414   // The GOT section.
 415   Output_data_got<32, false>* got_;
 416   // The PLT section.
 417   Output_data_plt_i386* plt_;
 418   // The GOT PLT section.
 419   Output_data_space* got_plt_;
 420   // The dynamic reloc section.
 421   Reloc_section* rel_dyn_;
 422   // Relocs saved to avoid a COPY reloc.
 423   Copy_relocs<elfcpp::SHT_REL, 32, false> copy_relocs_;
 424   // Space for variables copied with a COPY reloc.
 425   Output_data_space* dynbss_;
 426   // Offset of the GOT entry for the TLS module index.
 427   unsigned int got_mod_index_offset_;
 428   // True if the _TLS_MODULE_BASE_ symbol has been defined.
 429   bool tls_base_symbol_defined_;
 430 };
 431
 432 const Target::Target_info Target_i386::i386_info =
 433 {
 434   32,                   // size
 435   false,                // is_big_endian
 436   elfcpp::EM_386,       // machine_code
 437   false,                // has_make_symbol
 438   false,                // has_resolve
 439   true,                 // has_code_fill
 440   true,                 // is_default_stack_executable
 441   '\0',                 // wrap_char
 442   "/usr/lib/libc.so.1", // dynamic_linker
 443   0x08048000,           // default_text_segment_address
 444   0x1000,               // abi_pagesize (overridable by -z max-page-size)
 445   0x1000,               // common_pagesize (overridable by -z common-page-size)
 446   elfcpp::SHN_UNDEF,    // small_common_shndx
 447   elfcpp::SHN_UNDEF,    // large_common_shndx
 448   0,                    // small_common_section_flags
 449   0                     // large_common_section_flags
 450 };
 451
 452 // Get the GOT section, creating it if necessary.
 453
 454 Output_data_got<32, false>*
 455 Target_i386::got_section(Symbol_table* symtab, Layout* layout)
 456 {
 457   if (this->got_ == NULL)
 458     {
 459       gold_assert(symtab != NULL && layout != NULL);
 460
 461       this->got_ = new Output_data_got<32, false>();
 462
 463       Output_section* os;
 464       os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 465                                            (elfcpp::SHF_ALLOC
 466                                             | elfcpp::SHF_WRITE),
 467                                            this->got_, false);
 468       os->set_is_relro();
 469
 470       // The old GNU linker creates a .got.plt section.  We just
 471       // create another set of data in the .got section.  Note that we
 472       // always create a PLT if we create a GOT, although the PLT
 473       // might be empty.
 474       this->got_plt_ = new Output_data_space(4, "** GOT PLT");
 475       os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
 476                                            (elfcpp::SHF_ALLOC
 477                                             | elfcpp::SHF_WRITE),
 478                                            this->got_plt_, false);
 479       os->set_is_relro();
 480
 481       // The first three entries are reserved.
 482       this->got_plt_->set_current_data_size(3 * 4);
 483
 484       // Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
 485       symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
 486                                     this->got_plt_,
 487                                     0, 0, elfcpp::STT_OBJECT,
 488                                     elfcpp::STB_LOCAL,
 489                                     elfcpp::STV_HIDDEN, 0,
 490                                     false, false);
 491     }
 492
 493   return this->got_;
 494 }
 495
 496 // Get the dynamic reloc section, creating it if necessary.
 497
 498 Target_i386::Reloc_section*
 499 Target_i386::rel_dyn_section(Layout* layout)
 500 {
 501   if (this->rel_dyn_ == NULL)
 502     {
 503       gold_assert(layout != NULL);
 504       this->rel_dyn_ = new Reloc_section(parameters->options().combreloc());
 505       layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
 506                                       elfcpp::SHF_ALLOC, this->rel_dyn_, true);
 507     }
 508   return this->rel_dyn_;
 509 }
 510
 511 // A class to handle the PLT data.
 512
 513 class Output_data_plt_i386 : public Output_section_data
 514 {
 515  public:
 516   typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
 517
 518   Output_data_plt_i386(Layout*, Output_data_space*);
 519
 520   // Add an entry to the PLT.
 521   void
 522   add_entry(Symbol* gsym);
 523
 524   // Return the .rel.plt section data.
 525   const Reloc_section*
 526   rel_plt() const
 527   { return this->rel_; }
 528
 529  protected:
 530   void
 531   do_adjust_output_section(Output_section* os);
 532
 533   // Write to a map file.
 534   void
 535   do_print_to_mapfile(Mapfile* mapfile) const
 536   { mapfile->print_output_data(this, _("** PLT")); }
 537
 538  private:
 539   // The size of an entry in the PLT.
 540   static const int plt_entry_size = 16;
 541
 542   // The first entry in the PLT for an executable.
 543   static unsigned char exec_first_plt_entry[plt_entry_size];
 544
 545   // The first entry in the PLT for a shared object.
 546   static unsigned char dyn_first_plt_entry[plt_entry_size];
 547
 548   // Other entries in the PLT for an executable.
 549   static unsigned char exec_plt_entry[plt_entry_size];
 550
 551   // Other entries in the PLT for a shared object.
 552   static unsigned char dyn_plt_entry[plt_entry_size];
 553
 554   // Set the final size.
 555   void
 556   set_final_data_size()
 557   { this->set_data_size((this->count_ + 1) * plt_entry_size); }
 558
 559   // Write out the PLT data.
 560   void
 561   do_write(Output_file*);
 562
 563   // The reloc section.
 564   Reloc_section* rel_;
 565   // The .got.plt section.
 566   Output_data_space* got_plt_;
 567   // The number of PLT entries.
 568   unsigned int count_;
 569 };
 570
 571 // Create the PLT section.  The ordinary .got section is an argument,
 572 // since we need to refer to the start.  We also create our own .got
 573 // section just for PLT entries.
 574
 575 Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
 576                                            Output_data_space* got_plt)
 577   : Output_section_data(4), got_plt_(got_plt), count_(0)
 578 {
 579   this->rel_ = new Reloc_section(false);
 580   layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
 581                                   elfcpp::SHF_ALLOC, this->rel_, true);
 582 }
 583
 584 void
 585 Output_data_plt_i386::do_adjust_output_section(Output_section* os)
 586 {
 587   // UnixWare sets the entsize of .plt to 4, and so does the old GNU
 588   // linker, and so do we.
 589   os->set_entsize(4);
 590 }
 591
 592 // Add an entry to the PLT.
 593
 594 void
 595 Output_data_plt_i386::add_entry(Symbol* gsym)
 596 {
 597   gold_assert(!gsym->has_plt_offset());
 598
 599   // Note that when setting the PLT offset we skip the initial
 600   // reserved PLT entry.
 601   gsym->set_plt_offset((this->count_ + 1) * plt_entry_size);
 602
 603   ++this->count_;
 604
 605   section_offset_type got_offset = this->got_plt_->current_data_size();
 606
 607   // Every PLT entry needs a GOT entry which points back to the PLT
 608   // entry (this will be changed by the dynamic linker, normally
 609   // lazily when the function is called).
 610   this->got_plt_->set_current_data_size(got_offset + 4);
 611
 612   // Every PLT entry needs a reloc.
 613   gsym->set_needs_dynsym_entry();
 614   this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
 615                          got_offset);
 616
 617   // Note that we don't need to save the symbol.  The contents of the
 618   // PLT are independent of which symbols are used.  The symbols only
 619   // appear in the relocations.
 620 }
 621
 622 // The first entry in the PLT for an executable.
 623
 624 unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] =
 625 {
 626   0xff, 0x35,   // pushl contents of memory address
 627   0, 0, 0, 0,   // replaced with address of .got + 4
 628   0xff, 0x25,   // jmp indirect
 629   0, 0, 0, 0,   // replaced with address of .got + 8
 630   0, 0, 0, 0    // unused
 631 };
 632
 633 // The first entry in the PLT for a shared object.
 634
 635 unsigned char Output_data_plt_i386::dyn_first_plt_entry[plt_entry_size] =
 636 {
 637   0xff, 0xb3, 4, 0, 0, 0,       // pushl 4(%ebx)
 638   0xff, 0xa3, 8, 0, 0, 0,       // jmp *8(%ebx)
 639   0, 0, 0, 0                    // unused
 640 };
 641
 642 // Subsequent entries in the PLT for an executable.
 643
 644 unsigned char Output_data_plt_i386::exec_plt_entry[plt_entry_size] =
 645 {
 646   0xff, 0x25,   // jmp indirect
 647   0, 0, 0, 0,   // replaced with address of symbol in .got
 648   0x68,         // pushl immediate
 649   0, 0, 0, 0,   // replaced with offset into relocation table
 650   0xe9,         // jmp relative
 651   0, 0, 0, 0    // replaced with offset to start of .plt
 652 };
 653
 654 // Subsequent entries in the PLT for a shared object.
 655
 656 unsigned char Output_data_plt_i386::dyn_plt_entry[plt_entry_size] =
 657 {
 658   0xff, 0xa3,   // jmp *offset(%ebx)
 659   0, 0, 0, 0,   // replaced with offset of symbol in .got
 660   0x68,         // pushl immediate
 661   0, 0, 0, 0,   // replaced with offset into relocation table
 662   0xe9,         // jmp relative
 663   0, 0, 0, 0    // replaced with offset to start of .plt
 664 };
 665
 666 // Write out the PLT.  This uses the hand-coded instructions above,
 667 // and adjusts them as needed.  This is all specified by the i386 ELF
 668 // Processor Supplement.
 669
 670 void
 671 Output_data_plt_i386::do_write(Output_file* of)
 672 {
 673   const off_t offset = this->offset();
 674   const section_size_type oview_size =
 675     convert_to_section_size_type(this->data_size());
 676   unsigned char* const oview = of->get_output_view(offset, oview_size);
 677
 678   const off_t got_file_offset = this->got_plt_->offset();
 679   const section_size_type got_size =
 680     convert_to_section_size_type(this->got_plt_->data_size());
 681   unsigned char* const got_view = of->get_output_view(got_file_offset,
 682                                                       got_size);
 683
 684   unsigned char* pov = oview;
 685
 686   elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
 687   elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
 688
 689   if (parameters->options().output_is_position_independent())
 690     memcpy(pov, dyn_first_plt_entry, plt_entry_size);
 691   else
 692     {
 693       memcpy(pov, exec_first_plt_entry, plt_entry_size);
 694       elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 4);
 695       elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 8);
 696     }
 697   pov += plt_entry_size;
 698
 699   unsigned char* got_pov = got_view;
 700
 701   memset(got_pov, 0, 12);
 702   got_pov += 12;
 703
 704   const int rel_size = elfcpp::Elf_sizes<32>::rel_size;
 705
 706   unsigned int plt_offset = plt_entry_size;
 707   unsigned int plt_rel_offset = 0;
 708   unsigned int got_offset = 12;
 709   const unsigned int count = this->count_;
 710   for (unsigned int i = 0;
 711        i < count;
 712        ++i,
 713          pov += plt_entry_size,
 714          got_pov += 4,
 715          plt_offset += plt_entry_size,
 716          plt_rel_offset += rel_size,
 717          got_offset += 4)
 718     {
 719       // Set and adjust the PLT entry itself.
 720
 721       if (parameters->options().output_is_position_independent())
 722         {
 723           memcpy(pov, dyn_plt_entry, plt_entry_size);
 724           elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
 725         }
 726       else
 727         {
 728           memcpy(pov, exec_plt_entry, plt_entry_size);
 729           elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
 730                                                       (got_address
 731                                                        + got_offset));
 732         }
 733
 734       elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_rel_offset);
 735       elfcpp::Swap<32, false>::writeval(pov + 12,
 736                                         - (plt_offset + plt_entry_size));
 737
 738       // Set the entry in the GOT.
 739       elfcpp::Swap<32, false>::writeval(got_pov, plt_address + plt_offset + 6);
 740     }
 741
 742   gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
 743   gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
 744
 745   of->write_output_view(offset, oview_size, oview);
 746   of->write_output_view(got_file_offset, got_size, got_view);
 747 }
 748
 749 // Create a PLT entry for a global symbol.
 750
 751 void
 752 Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
 753 {
 754   if (gsym->has_plt_offset())
 755     return;
 756
 757   if (this->plt_ == NULL)
 758     {
 759       // Create the GOT sections first.
 760       this->got_section(symtab, layout);
 761
 762       this->plt_ = new Output_data_plt_i386(layout, this->got_plt_);
 763       layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
 764                                       (elfcpp::SHF_ALLOC
 765                                        | elfcpp::SHF_EXECINSTR),
 766                                       this->plt_, false);
 767     }
 768
 769   this->plt_->add_entry(gsym);
 770 }
 771
 772 // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
 773
 774 void
 775 Target_i386::define_tls_base_symbol(Symbol_table* symtab, Layout* layout)
 776 {
 777   if (this->tls_base_symbol_defined_)
 778     return;
 779
 780   Output_segment* tls_segment = layout->tls_segment();
 781   if (tls_segment != NULL)
 782     {
 783       bool is_exec = parameters->options().output_is_executable();
 784       symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
 785                                        tls_segment, 0, 0,
 786                                        elfcpp::STT_TLS,
 787                                        elfcpp::STB_LOCAL,
 788                                        elfcpp::STV_HIDDEN, 0,
 789                                        (is_exec
 790                                         ? Symbol::SEGMENT_END
 791                                         : Symbol::SEGMENT_START),
 792                                        true);
 793     }
 794   this->tls_base_symbol_defined_ = true;
 795 }
 796
 797 // Create a GOT entry for the TLS module index.
 798
 799 unsigned int
 800 Target_i386::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
 801                                  Sized_relobj<32, false>* object)
 802 {
 803   if (this->got_mod_index_offset_ == -1U)
 804     {
 805       gold_assert(symtab != NULL && layout != NULL && object != NULL);
 806       Reloc_section* rel_dyn = this->rel_dyn_section(layout);
 807       Output_data_got<32, false>* got = this->got_section(symtab, layout);
 808       unsigned int got_offset = got->add_constant(0);
 809       rel_dyn->add_local(object, 0, elfcpp::R_386_TLS_DTPMOD32, got,
 810                          got_offset);
 811       got->add_constant(0);
 812       this->got_mod_index_offset_ = got_offset;
 813     }
 814   return this->got_mod_index_offset_;
 815 }
 816
 817 // Optimize the TLS relocation type based on what we know about the
 818 // symbol.  IS_FINAL is true if the final address of this symbol is
 819 // known at link time.
 820
 821 tls::Tls_optimization
 822 Target_i386::optimize_tls_reloc(bool is_final, int r_type)
 823 {
 824   // If we are generating a shared library, then we can't do anything
 825   // in the linker.
 826   if (parameters->options().shared())
 827     return tls::TLSOPT_NONE;
 828
 829   switch (r_type)
 830     {
 831     case elfcpp::R_386_TLS_GD:
 832     case elfcpp::R_386_TLS_GOTDESC:
 833     case elfcpp::R_386_TLS_DESC_CALL:
 834       // These are General-Dynamic which permits fully general TLS
 835       // access.  Since we know that we are generating an executable,
 836       // we can convert this to Initial-Exec.  If we also know that
 837       // this is a local symbol, we can further switch to Local-Exec.
 838       if (is_final)
 839         return tls::TLSOPT_TO_LE;
 840       return tls::TLSOPT_TO_IE;
 841
 842     case elfcpp::R_386_TLS_LDM:
 843       // This is Local-Dynamic, which refers to a local symbol in the
 844       // dynamic TLS block.  Since we know that we generating an
 845       // executable, we can switch to Local-Exec.
 846       return tls::TLSOPT_TO_LE;
 847
 848     case elfcpp::R_386_TLS_LDO_32:
 849       // Another type of Local-Dynamic relocation.
 850       return tls::TLSOPT_TO_LE;
 851
 852     case elfcpp::R_386_TLS_IE:
 853     case elfcpp::R_386_TLS_GOTIE:
 854     case elfcpp::R_386_TLS_IE_32:
 855       // These are Initial-Exec relocs which get the thread offset
 856       // from the GOT.  If we know that we are linking against the
 857       // local symbol, we can switch to Local-Exec, which links the
 858       // thread offset into the instruction.
 859       if (is_final)
 860         return tls::TLSOPT_TO_LE;
 861       return tls::TLSOPT_NONE;
 862
 863     case elfcpp::R_386_TLS_LE:
 864     case elfcpp::R_386_TLS_LE_32:
 865       // When we already have Local-Exec, there is nothing further we
 866       // can do.
 867       return tls::TLSOPT_NONE;
 868
 869     default:
 870       gold_unreachable();
 871     }
 872 }
 873
 874 // Report an unsupported relocation against a local symbol.
 875
 876 void
 877 Target_i386::Scan::unsupported_reloc_local(Sized_relobj<32, false>* object,
 878                                            unsigned int r_type)
 879 {
 880   gold_error(_("%s: unsupported reloc %u against local symbol"),
 881              object->name().c_str(), r_type);
 882 }
 883
 884 // Scan a relocation for a local symbol.
 885
 886 inline void
 887 Target_i386::Scan::local(const General_options&,
 888                          Symbol_table* symtab,
 889                          Layout* layout,
 890                          Target_i386* target,
 891                          Sized_relobj<32, false>* object,
 892                          unsigned int data_shndx,
 893                          Output_section* output_section,
 894                          const elfcpp::Rel<32, false>& reloc,
 895                          unsigned int r_type,
 896                          const elfcpp::Sym<32, false>& lsym)
 897 {
 898   switch (r_type)
 899     {
 900     case elfcpp::R_386_NONE:
 901     case elfcpp::R_386_GNU_VTINHERIT:
 902     case elfcpp::R_386_GNU_VTENTRY:
 903       break;
 904
 905     case elfcpp::R_386_32:
 906       // If building a shared library (or a position-independent
 907       // executable), we need to create a dynamic relocation for
 908       // this location. The relocation applied at link time will
 909       // apply the link-time value, so we flag the location with
 910       // an R_386_RELATIVE relocation so the dynamic loader can
 911       // relocate it easily.
 912       if (parameters->options().output_is_position_independent())
 913         {
 914           Reloc_section* rel_dyn = target->rel_dyn_section(layout);
 915           unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
 916           rel_dyn->add_local_relative(object, r_sym, elfcpp::R_386_RELATIVE,
 917                                       output_section, data_shndx,
 918                                       reloc.get_r_offset());
 919         }
 920       break;
 921
 922     case elfcpp::R_386_16:
 923     case elfcpp::R_386_8:
 924       // If building a shared library (or a position-independent
 925       // executable), we need to create a dynamic relocation for
 926       // this location. Because the addend needs to remain in the
 927       // data section, we need to be careful not to apply this
 928       // relocation statically.
 929       if (parameters->options().output_is_position_independent())
 930         {
 931           Reloc_section* rel_dyn = target->rel_dyn_section(layout);
 932           unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
 933           if (lsym.get_st_type() != elfcpp::STT_SECTION)
 934             rel_dyn->add_local(object, r_sym, r_type, output_section,
 935                                data_shndx, reloc.get_r_offset());
 936           else
 937             {
 938               gold_assert(lsym.get_st_value() == 0);
 939               unsigned int shndx = lsym.get_st_shndx();
 940               bool is_ordinary;
 941               shndx = object->adjust_sym_shndx(r_sym, shndx,
 942                                                &is_ordinary);
 943               if (!is_ordinary)
 944                 object->error(_("section symbol %u has bad shndx %u"),
 945                               r_sym, shndx);
 946               else
 947                 rel_dyn->add_local_section(object, shndx,
 948                                            r_type, output_section,
 949                                            data_shndx, reloc.get_r_offset());
 950             }
 951         }
 952       break;
 953
 954     case elfcpp::R_386_PC32:
 955     case elfcpp::R_386_PC16:
 956     case elfcpp::R_386_PC8:
 957       break;
 958
 959     case elfcpp::R_386_PLT32:
 960       // Since we know this is a local symbol, we can handle this as a
 961       // PC32 reloc.
 962       break;
 963
 964     case elfcpp::R_386_GOTOFF:
 965     case elfcpp::R_386_GOTPC:
 966       // We need a GOT section.
 967       target->got_section(symtab, layout);
 968       break;
 969
 970     case elfcpp::R_386_GOT32:
 971       {
 972         // The symbol requires a GOT entry.
 973         Output_data_got<32, false>* got = target->got_section(symtab, layout);
 974         unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
 975         if (got->add_local(object, r_sym, GOT_TYPE_STANDARD))
 976           {
 977             // If we are generating a shared object, we need to add a
 978             // dynamic RELATIVE relocation for this symbol's GOT entry.
 979             if (parameters->options().output_is_position_independent())
 980               {
 981                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
 982                 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
 983                 rel_dyn->add_local_relative(
 984                     object, r_sym, elfcpp::R_386_RELATIVE, got,
 985                     object->local_got_offset(r_sym, GOT_TYPE_STANDARD));
 986               }
 987           }
 988       }
 989       break;
 990
 991       // These are relocations which should only be seen by the
 992       // dynamic linker, and should never be seen here.
 993     case elfcpp::R_386_COPY:
 994     case elfcpp::R_386_GLOB_DAT:
 995     case elfcpp::R_386_JUMP_SLOT:
 996     case elfcpp::R_386_RELATIVE:
 997     case elfcpp::R_386_TLS_TPOFF:
 998     case elfcpp::R_386_TLS_DTPMOD32:
 999     case elfcpp::R_386_TLS_DTPOFF32:
1000     case elfcpp::R_386_TLS_TPOFF32:
1001     case elfcpp::R_386_TLS_DESC:
1002       gold_error(_("%s: unexpected reloc %u in object file"),
1003                  object->name().c_str(), r_type);
1004       break;
1005
1006       // These are initial TLS relocs, which are expected when
1007       // linking.
1008     case elfcpp::R_386_TLS_GD:            // Global-dynamic
1009     case elfcpp::R_386_TLS_GOTDESC:       // Global-dynamic (from ~oliva url)
1010     case elfcpp::R_386_TLS_DESC_CALL:
1011     case elfcpp::R_386_TLS_LDM:           // Local-dynamic
1012     case elfcpp::R_386_TLS_LDO_32:        // Alternate local-dynamic
1013     case elfcpp::R_386_TLS_IE:            // Initial-exec
1014     case elfcpp::R_386_TLS_IE_32:
1015     case elfcpp::R_386_TLS_GOTIE:
1016     case elfcpp::R_386_TLS_LE:            // Local-exec
1017     case elfcpp::R_386_TLS_LE_32:
1018       {
1019         bool output_is_shared = parameters->options().shared();
1020         const tls::Tls_optimization optimized_type
1021             = Target_i386::optimize_tls_reloc(!output_is_shared, r_type);
1022         switch (r_type)
1023           {
1024           case elfcpp::R_386_TLS_GD:          // Global-dynamic
1025             if (optimized_type == tls::TLSOPT_NONE)
1026               {
1027                 // Create a pair of GOT entries for the module index and
1028                 // dtv-relative offset.
1029                 Output_data_got<32, false>* got
1030                     = target->got_section(symtab, layout);
1031                 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1032                 unsigned int shndx = lsym.get_st_shndx();
1033                 bool is_ordinary;
1034                 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1035                 if (!is_ordinary)
1036                   object->error(_("local symbol %u has bad shndx %u"),
1037                               r_sym, shndx);
1038                 else
1039                   got->add_local_pair_with_rel(object, r_sym, shndx,
1040                                                GOT_TYPE_TLS_PAIR,
1041                                                target->rel_dyn_section(layout),
1042                                                elfcpp::R_386_TLS_DTPMOD32, 0);
1043               }
1044             else if (optimized_type != tls::TLSOPT_TO_LE)
1045               unsupported_reloc_local(object, r_type);
1046             break;
1047
1048           case elfcpp::R_386_TLS_GOTDESC:     // Global-dynamic (from ~oliva)
1049             target->define_tls_base_symbol(symtab, layout);
1050             if (optimized_type == tls::TLSOPT_NONE)
1051               {
1052                 // Create a double GOT entry with an R_386_TLS_DESC reloc.
1053                 Output_data_got<32, false>* got
1054                     = target->got_section(symtab, layout);
1055                 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1056                 unsigned int shndx = lsym.get_st_shndx();
1057                 bool is_ordinary;
1058                 shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
1059                 if (!is_ordinary)
1060                   object->error(_("local symbol %u has bad shndx %u"),
1061                               r_sym, shndx);
1062                 else
1063                   got->add_local_pair_with_rel(object, r_sym, shndx,
1064                                                GOT_TYPE_TLS_DESC,
1065                                                target->rel_dyn_section(layout),
1066                                                elfcpp::R_386_TLS_DESC, 0);
1067               }
1068             else if (optimized_type != tls::TLSOPT_TO_LE)
1069               unsupported_reloc_local(object, r_type);
1070             break;
1071
1072           case elfcpp::R_386_TLS_DESC_CALL:
1073             break;
1074
1075           case elfcpp::R_386_TLS_LDM:         // Local-dynamic
1076             if (optimized_type == tls::TLSOPT_NONE)
1077               {
1078                 // Create a GOT entry for the module index.
1079                 target->got_mod_index_entry(symtab, layout, object);
1080               }
1081             else if (optimized_type != tls::TLSOPT_TO_LE)
1082               unsupported_reloc_local(object, r_type);
1083             break;
1084
1085           case elfcpp::R_386_TLS_LDO_32:      // Alternate local-dynamic
1086             break;
1087
1088           case elfcpp::R_386_TLS_IE:          // Initial-exec
1089           case elfcpp::R_386_TLS_IE_32:
1090           case elfcpp::R_386_TLS_GOTIE:
1091             layout->set_has_static_tls();
1092             if (optimized_type == tls::TLSOPT_NONE)
1093               {
1094                 // For the R_386_TLS_IE relocation, we need to create a
1095                 // dynamic relocation when building a shared library.
1096                 if (r_type == elfcpp::R_386_TLS_IE
1097                     && parameters->options().shared())
1098                   {
1099                     Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1100                     unsigned int r_sym
1101                         = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1102                     rel_dyn->add_local_relative(object, r_sym,
1103                                                 elfcpp::R_386_RELATIVE,
1104                                                 output_section, data_shndx,
1105                                                 reloc.get_r_offset());
1106                   }
1107                 // Create a GOT entry for the tp-relative offset.
1108                 Output_data_got<32, false>* got
1109                     = target->got_section(symtab, layout);
1110                 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1111                 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
1112                                            ? elfcpp::R_386_TLS_TPOFF32
1113                                            : elfcpp::R_386_TLS_TPOFF);
1114                 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
1115                                          ? GOT_TYPE_TLS_OFFSET
1116                                          : GOT_TYPE_TLS_NOFFSET);
1117                 got->add_local_with_rel(object, r_sym, got_type,
1118                                         target->rel_dyn_section(layout),
1119                                         dyn_r_type);
1120               }
1121             else if (optimized_type != tls::TLSOPT_TO_LE)
1122               unsupported_reloc_local(object, r_type);
1123             break;
1124
1125           case elfcpp::R_386_TLS_LE:          // Local-exec
1126           case elfcpp::R_386_TLS_LE_32:
1127             layout->set_has_static_tls();
1128             if (output_is_shared)
1129               {
1130                 // We need to create a dynamic relocation.
1131                 gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
1132                 unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
1133                 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
1134                                            ? elfcpp::R_386_TLS_TPOFF32
1135                                            : elfcpp::R_386_TLS_TPOFF);
1136                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1137                 rel_dyn->add_local(object, r_sym, dyn_r_type, output_section,
1138                                    data_shndx, reloc.get_r_offset());
1139               }
1140             break;
1141
1142           default:
1143             gold_unreachable();
1144           }
1145       }
1146       break;
1147
1148     case elfcpp::R_386_32PLT:
1149     case elfcpp::R_386_TLS_GD_32:
1150     case elfcpp::R_386_TLS_GD_PUSH:
1151     case elfcpp::R_386_TLS_GD_CALL:
1152     case elfcpp::R_386_TLS_GD_POP:
1153     case elfcpp::R_386_TLS_LDM_32:
1154     case elfcpp::R_386_TLS_LDM_PUSH:
1155     case elfcpp::R_386_TLS_LDM_CALL:
1156     case elfcpp::R_386_TLS_LDM_POP:
1157     case elfcpp::R_386_USED_BY_INTEL_200:
1158     default:
1159       unsupported_reloc_local(object, r_type);
1160       break;
1161     }
1162 }
1163
1164 // Report an unsupported relocation against a global symbol.
1165
1166 void
1167 Target_i386::Scan::unsupported_reloc_global(Sized_relobj<32, false>* object,
1168                                             unsigned int r_type,
1169                                             Symbol* gsym)
1170 {
1171   gold_error(_("%s: unsupported reloc %u against global symbol %s"),
1172              object->name().c_str(), r_type, gsym->demangled_name().c_str());
1173 }
1174
1175 // Scan a relocation for a global symbol.
1176
1177 inline void
1178 Target_i386::Scan::global(const General_options&,
1179                           Symbol_table* symtab,
1180                           Layout* layout,
1181                           Target_i386* target,
1182                           Sized_relobj<32, false>* object,
1183                           unsigned int data_shndx,
1184                           Output_section* output_section,
1185                           const elfcpp::Rel<32, false>& reloc,
1186                           unsigned int r_type,
1187                           Symbol* gsym)
1188 {
1189   switch (r_type)
1190     {
1191     case elfcpp::R_386_NONE:
1192     case elfcpp::R_386_GNU_VTINHERIT:
1193     case elfcpp::R_386_GNU_VTENTRY:
1194       break;
1195
1196     case elfcpp::R_386_32:
1197     case elfcpp::R_386_16:
1198     case elfcpp::R_386_8:
1199       {
1200         // Make a PLT entry if necessary.
1201         if (gsym->needs_plt_entry())
1202           {
1203             target->make_plt_entry(symtab, layout, gsym);
1204             // Since this is not a PC-relative relocation, we may be
1205             // taking the address of a function. In that case we need to
1206             // set the entry in the dynamic symbol table to the address of
1207             // the PLT entry.
1208             if (gsym->is_from_dynobj() && !parameters->options().shared())
1209               gsym->set_needs_dynsym_value();
1210           }
1211         // Make a dynamic relocation if necessary.
1212         if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF))
1213           {
1214             if (gsym->may_need_copy_reloc())
1215               {
1216                 target->copy_reloc(symtab, layout, object,
1217                                    data_shndx, output_section, gsym, reloc);
1218               }
1219             else if (r_type == elfcpp::R_386_32
1220                      && gsym->can_use_relative_reloc(false))
1221               {
1222                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1223                 rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
1224                                              output_section, object,
1225                                              data_shndx, reloc.get_r_offset());
1226               }
1227             else
1228               {
1229                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1230                 rel_dyn->add_global(gsym, r_type, output_section, object,
1231                                     data_shndx, reloc.get_r_offset());
1232               }
1233           }
1234       }
1235       break;
1236
1237     case elfcpp::R_386_PC32:
1238     case elfcpp::R_386_PC16:
1239     case elfcpp::R_386_PC8:
1240       {
1241         // Make a PLT entry if necessary.
1242         if (gsym->needs_plt_entry())
1243           {
1244             // These relocations are used for function calls only in
1245             // non-PIC code.  For a 32-bit relocation in a shared library,
1246             // we'll need a text relocation anyway, so we can skip the
1247             // PLT entry and let the dynamic linker bind the call directly
1248             // to the target.  For smaller relocations, we should use a
1249             // PLT entry to ensure that the call can reach.
1250             if (!parameters->options().shared()
1251                 || r_type != elfcpp::R_386_PC32)
1252               target->make_plt_entry(symtab, layout, gsym);
1253           }
1254         // Make a dynamic relocation if necessary.
1255         int flags = Symbol::NON_PIC_REF;
1256         if (gsym->type() == elfcpp::STT_FUNC)
1257           flags |= Symbol::FUNCTION_CALL;
1258         if (gsym->needs_dynamic_reloc(flags))
1259           {
1260             if (gsym->may_need_copy_reloc())
1261               {
1262                 target->copy_reloc(symtab, layout, object,
1263                                    data_shndx, output_section, gsym, reloc);
1264               }
1265             else
1266               {
1267                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1268                 rel_dyn->add_global(gsym, r_type, output_section, object,
1269                                     data_shndx, reloc.get_r_offset());
1270               }
1271           }
1272       }
1273       break;
1274
1275     case elfcpp::R_386_GOT32:
1276       {
1277         // The symbol requires a GOT entry.
1278         Output_data_got<32, false>* got = target->got_section(symtab, layout);
1279         if (gsym->final_value_is_known())
1280           got->add_global(gsym, GOT_TYPE_STANDARD);
1281         else
1282           {
1283             // If this symbol is not fully resolved, we need to add a
1284             // GOT entry with a dynamic relocation.
1285             Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1286             if (gsym->is_from_dynobj()
1287                 || gsym->is_undefined()
1288                 || gsym->is_preemptible())
1289               got->add_global_with_rel(gsym, GOT_TYPE_STANDARD,
1290                                        rel_dyn, elfcpp::R_386_GLOB_DAT);
1291             else
1292               {
1293                 if (got->add_global(gsym, GOT_TYPE_STANDARD))
1294                   rel_dyn->add_global_relative(
1295                       gsym, elfcpp::R_386_RELATIVE, got,
1296                       gsym->got_offset(GOT_TYPE_STANDARD));
1297               }
1298           }
1299       }
1300       break;
1301
1302     case elfcpp::R_386_PLT32:
1303       // If the symbol is fully resolved, this is just a PC32 reloc.
1304       // Otherwise we need a PLT entry.
1305       if (gsym->final_value_is_known())
1306         break;
1307       // If building a shared library, we can also skip the PLT entry
1308       // if the symbol is defined in the output file and is protected
1309       // or hidden.
1310       if (gsym->is_defined()
1311           && !gsym->is_from_dynobj()
1312           && !gsym->is_preemptible())
1313         break;
1314       target->make_plt_entry(symtab, layout, gsym);
1315       break;
1316
1317     case elfcpp::R_386_GOTOFF:
1318     case elfcpp::R_386_GOTPC:
1319       // We need a GOT section.
1320       target->got_section(symtab, layout);
1321       break;
1322
1323       // These are relocations which should only be seen by the
1324       // dynamic linker, and should never be seen here.
1325     case elfcpp::R_386_COPY:
1326     case elfcpp::R_386_GLOB_DAT:
1327     case elfcpp::R_386_JUMP_SLOT:
1328     case elfcpp::R_386_RELATIVE:
1329     case elfcpp::R_386_TLS_TPOFF:
1330     case elfcpp::R_386_TLS_DTPMOD32:
1331     case elfcpp::R_386_TLS_DTPOFF32:
1332     case elfcpp::R_386_TLS_TPOFF32:
1333     case elfcpp::R_386_TLS_DESC:
1334       gold_error(_("%s: unexpected reloc %u in object file"),
1335                  object->name().c_str(), r_type);
1336       break;
1337
1338       // These are initial tls relocs, which are expected when
1339       // linking.
1340     case elfcpp::R_386_TLS_GD:            // Global-dynamic
1341     case elfcpp::R_386_TLS_GOTDESC:       // Global-dynamic (from ~oliva url)
1342     case elfcpp::R_386_TLS_DESC_CALL:
1343     case elfcpp::R_386_TLS_LDM:           // Local-dynamic
1344     case elfcpp::R_386_TLS_LDO_32:        // Alternate local-dynamic
1345     case elfcpp::R_386_TLS_IE:            // Initial-exec
1346     case elfcpp::R_386_TLS_IE_32:
1347     case elfcpp::R_386_TLS_GOTIE:
1348     case elfcpp::R_386_TLS_LE:            // Local-exec
1349     case elfcpp::R_386_TLS_LE_32:
1350       {
1351         const bool is_final = gsym->final_value_is_known();
1352         const tls::Tls_optimization optimized_type
1353             = Target_i386::optimize_tls_reloc(is_final, r_type);
1354         switch (r_type)
1355           {
1356           case elfcpp::R_386_TLS_GD:          // Global-dynamic
1357             if (optimized_type == tls::TLSOPT_NONE)
1358               {
1359                 // Create a pair of GOT entries for the module index and
1360                 // dtv-relative offset.
1361                 Output_data_got<32, false>* got
1362                     = target->got_section(symtab, layout);
1363                 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_PAIR,
1364                                              target->rel_dyn_section(layout),
1365                                              elfcpp::R_386_TLS_DTPMOD32,
1366                                              elfcpp::R_386_TLS_DTPOFF32);
1367               }
1368             else if (optimized_type == tls::TLSOPT_TO_IE)
1369               {
1370                 // Create a GOT entry for the tp-relative offset.
1371                 Output_data_got<32, false>* got
1372                     = target->got_section(symtab, layout);
1373                 got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET,
1374                                          target->rel_dyn_section(layout),
1375                                          elfcpp::R_386_TLS_TPOFF);
1376               }
1377             else if (optimized_type != tls::TLSOPT_TO_LE)
1378               unsupported_reloc_global(object, r_type, gsym);
1379             break;
1380
1381           case elfcpp::R_386_TLS_GOTDESC:     // Global-dynamic (~oliva url)
1382             target->define_tls_base_symbol(symtab, layout);
1383             if (optimized_type == tls::TLSOPT_NONE)
1384               {
1385                 // Create a double GOT entry with an R_386_TLS_DESC reloc.
1386                 Output_data_got<32, false>* got
1387                     = target->got_section(symtab, layout);
1388                 got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC,
1389                                              target->rel_dyn_section(layout),
1390                                              elfcpp::R_386_TLS_DESC, 0);
1391               }
1392             else if (optimized_type == tls::TLSOPT_TO_IE)
1393               {
1394                 // Create a GOT entry for the tp-relative offset.
1395                 Output_data_got<32, false>* got
1396                     = target->got_section(symtab, layout);
1397                 got->add_global_with_rel(gsym, GOT_TYPE_TLS_NOFFSET,
1398                                          target->rel_dyn_section(layout),
1399                                          elfcpp::R_386_TLS_TPOFF);
1400               }
1401             else if (optimized_type != tls::TLSOPT_TO_LE)
1402               unsupported_reloc_global(object, r_type, gsym);
1403             break;
1404
1405           case elfcpp::R_386_TLS_DESC_CALL:
1406             break;
1407
1408           case elfcpp::R_386_TLS_LDM:         // Local-dynamic
1409             if (optimized_type == tls::TLSOPT_NONE)
1410               {
1411                 // Create a GOT entry for the module index.
1412                 target->got_mod_index_entry(symtab, layout, object);
1413               }
1414             else if (optimized_type != tls::TLSOPT_TO_LE)
1415               unsupported_reloc_global(object, r_type, gsym);
1416             break;
1417
1418           case elfcpp::R_386_TLS_LDO_32:      // Alternate local-dynamic
1419             break;
1420
1421           case elfcpp::R_386_TLS_IE:          // Initial-exec
1422           case elfcpp::R_386_TLS_IE_32:
1423           case elfcpp::R_386_TLS_GOTIE:
1424             layout->set_has_static_tls();
1425             if (optimized_type == tls::TLSOPT_NONE)
1426               {
1427                 // For the R_386_TLS_IE relocation, we need to create a
1428                 // dynamic relocation when building a shared library.
1429                 if (r_type == elfcpp::R_386_TLS_IE
1430                     && parameters->options().shared())
1431                   {
1432                     Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1433                     rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
1434                                                  output_section, object,
1435                                                  data_shndx,
1436                                                  reloc.get_r_offset());
1437                   }
1438                 // Create a GOT entry for the tp-relative offset.
1439                 Output_data_got<32, false>* got
1440                     = target->got_section(symtab, layout);
1441                 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_IE_32
1442                                            ? elfcpp::R_386_TLS_TPOFF32
1443                                            : elfcpp::R_386_TLS_TPOFF);
1444                 unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
1445                                          ? GOT_TYPE_TLS_OFFSET
1446                                          : GOT_TYPE_TLS_NOFFSET);
1447                 got->add_global_with_rel(gsym, got_type,
1448                                          target->rel_dyn_section(layout),
1449                                          dyn_r_type);
1450               }
1451             else if (optimized_type != tls::TLSOPT_TO_LE)
1452               unsupported_reloc_global(object, r_type, gsym);
1453             break;
1454
1455           case elfcpp::R_386_TLS_LE:          // Local-exec
1456           case elfcpp::R_386_TLS_LE_32:
1457             layout->set_has_static_tls();
1458             if (parameters->options().shared())
1459               {
1460                 // We need to create a dynamic relocation.
1461                 unsigned int dyn_r_type = (r_type == elfcpp::R_386_TLS_LE_32
1462                                            ? elfcpp::R_386_TLS_TPOFF32
1463                                            : elfcpp::R_386_TLS_TPOFF);
1464                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
1465                 rel_dyn->add_global(gsym, dyn_r_type, output_section, object,
1466                                     data_shndx, reloc.get_r_offset());
1467               }
1468             break;
1469
1470           default:
1471             gold_unreachable();
1472           }
1473       }
1474       break;
1475
1476     case elfcpp::R_386_32PLT:
1477     case elfcpp::R_386_TLS_GD_32:
1478     case elfcpp::R_386_TLS_GD_PUSH:
1479     case elfcpp::R_386_TLS_GD_CALL:
1480     case elfcpp::R_386_TLS_GD_POP:
1481     case elfcpp::R_386_TLS_LDM_32:
1482     case elfcpp::R_386_TLS_LDM_PUSH:
1483     case elfcpp::R_386_TLS_LDM_CALL:
1484     case elfcpp::R_386_TLS_LDM_POP:
1485     case elfcpp::R_386_USED_BY_INTEL_200:
1486     default:
1487       unsupported_reloc_global(object, r_type, gsym);
1488       break;
1489     }
1490 }
1491
1492 // Process relocations for gc.
1493
1494 void
1495 Target_i386::gc_process_relocs(const General_options& options,
1496                                Symbol_table* symtab,
1497                                Layout* layout,
1498                                Sized_relobj<32, false>* object,
1499                                unsigned int data_shndx,
1500                                unsigned int,
1501                                const unsigned char* prelocs,
1502                                size_t reloc_count,
1503                                Output_section* output_section,
1504                                bool needs_special_offset_handling,
1505                                size_t local_symbol_count,
1506                                const unsigned char* plocal_symbols)
1507 {
1508   gold::gc_process_relocs<32, false, Target_i386, elfcpp::SHT_REL,
1509                           Target_i386::Scan>(
1510     options,
1511     symtab,
1512     layout,
1513     this,
1514     object,
1515     data_shndx,
1516     prelocs,
1517     reloc_count,
1518     output_section,
1519     needs_special_offset_handling,
1520     local_symbol_count,
1521     plocal_symbols);
1522 }
1523
1524 // Scan relocations for a section.
1525
1526 void
1527 Target_i386::scan_relocs(const General_options& options,
1528                          Symbol_table* symtab,
1529                          Layout* layout,
1530                          Sized_relobj<32, false>* object,
1531                          unsigned int data_shndx,
1532                          unsigned int sh_type,
1533                          const unsigned char* prelocs,
1534                          size_t reloc_count,
1535                          Output_section* output_section,
1536                          bool needs_special_offset_handling,
1537                          size_t local_symbol_count,
1538                          const unsigned char* plocal_symbols)
1539 {
1540   if (sh_type == elfcpp::SHT_RELA)
1541     {
1542       gold_error(_("%s: unsupported RELA reloc section"),
1543                  object->name().c_str());
1544       return;
1545     }
1546
1547   gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL,
1548                     Target_i386::Scan>(
1549     options,
1550     symtab,
1551     layout,
1552     this,
1553     object,
1554     data_shndx,
1555     prelocs,
1556     reloc_count,
1557     output_section,
1558     needs_special_offset_handling,
1559     local_symbol_count,
1560     plocal_symbols);
1561 }
1562
1563 // Finalize the sections.
1564
1565 void
1566 Target_i386::do_finalize_sections(Layout* layout)
1567 {
1568   // Fill in some more dynamic tags.
1569   Output_data_dynamic* const odyn = layout->dynamic_data();
1570   if (odyn != NULL)
1571     {
1572       if (this->got_plt_ != NULL
1573           && this->got_plt_->output_section() != NULL)
1574         odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_);
1575
1576       if (this->plt_ != NULL
1577           && this->plt_->output_section() != NULL)
1578         {
1579           const Output_data* od = this->plt_->rel_plt();
1580           odyn->add_section_size(elfcpp::DT_PLTRELSZ, od);
1581           odyn->add_section_address(elfcpp::DT_JMPREL, od);
1582           odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_REL);
1583         }
1584
1585       if (this->rel_dyn_ != NULL
1586           && this->rel_dyn_->output_section() != NULL)
1587         {
1588           const Output_data* od = this->rel_dyn_;
1589           odyn->add_section_address(elfcpp::DT_REL, od);
1590           odyn->add_section_size(elfcpp::DT_RELSZ, od);
1591           odyn->add_constant(elfcpp::DT_RELENT,
1592                              elfcpp::Elf_sizes<32>::rel_size);
1593         }
1594
1595       if (!parameters->options().shared())
1596         {
1597           // The value of the DT_DEBUG tag is filled in by the dynamic
1598           // linker at run time, and used by the debugger.
1599           odyn->add_constant(elfcpp::DT_DEBUG, 0);
1600         }
1601     }
1602
1603   // Emit any relocs we saved in an attempt to avoid generating COPY
1604   // relocs.
1605   if (this->copy_relocs_.any_saved_relocs())
1606     this->copy_relocs_.emit(this->rel_dyn_section(layout));
1607 }
1608
1609 // Return whether a direct absolute static relocation needs to be applied.
1610 // In cases where Scan::local() or Scan::global() has created
1611 // a dynamic relocation other than R_386_RELATIVE, the addend
1612 // of the relocation is carried in the data, and we must not
1613 // apply the static relocation.
1614
1615 inline bool
1616 Target_i386::Relocate::should_apply_static_reloc(const Sized_symbol<32>* gsym,
1617                                                  int ref_flags,
1618                                                  bool is_32bit,
1619                                                  Output_section* output_section)
1620 {
1621   // If the output section is not allocated, then we didn't call
1622   // scan_relocs, we didn't create a dynamic reloc, and we must apply
1623   // the reloc here.
1624   if ((output_section->flags() & elfcpp::SHF_ALLOC) == 0)
1625     return true;
1626
1627   // For local symbols, we will have created a non-RELATIVE dynamic
1628   // relocation only if (a) the output is position independent,
1629   // (b) the relocation is absolute (not pc- or segment-relative), and
1630   // (c) the relocation is not 32 bits wide.
1631   if (gsym == NULL)
1632     return !(parameters->options().output_is_position_independent()
1633              && (ref_flags & Symbol::ABSOLUTE_REF)
1634              && !is_32bit);
1635
1636   // For global symbols, we use the same helper routines used in the
1637   // scan pass.  If we did not create a dynamic relocation, or if we
1638   // created a RELATIVE dynamic relocation, we should apply the static
1639   // relocation.
1640   bool has_dyn = gsym->needs_dynamic_reloc(ref_flags);
1641   bool is_rel = (ref_flags & Symbol::ABSOLUTE_REF)
1642                 && gsym->can_use_relative_reloc(ref_flags
1643                                                 & Symbol::FUNCTION_CALL);
1644   return !has_dyn || is_rel;
1645 }
1646
1647 // Perform a relocation.
1648
1649 inline bool
1650 Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
1651                                 Target_i386* target,
1652                                 Output_section *output_section,
1653                                 size_t relnum,
1654                                 const elfcpp::Rel<32, false>& rel,
1655                                 unsigned int r_type,
1656                                 const Sized_symbol<32>* gsym,
1657                                 const Symbol_value<32>* psymval,
1658                                 unsigned char* view,
1659                                 elfcpp::Elf_types<32>::Elf_Addr address,
1660                                 section_size_type view_size)
1661 {
1662   if (this->skip_call_tls_get_addr_)
1663     {
1664       if ((r_type != elfcpp::R_386_PLT32
1665            && r_type != elfcpp::R_386_PC32)
1666           || gsym == NULL
1667           || strcmp(gsym->name(), "___tls_get_addr") != 0)
1668         gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1669                                _("missing expected TLS relocation"));
1670       else
1671         {
1672           this->skip_call_tls_get_addr_ = false;
1673           return false;
1674         }
1675     }
1676
1677   // Pick the value to use for symbols defined in shared objects.
1678   Symbol_value<32> symval;
1679   if (gsym != NULL
1680       && gsym->use_plt_offset(r_type == elfcpp::R_386_PC8
1681                               || r_type == elfcpp::R_386_PC16
1682                               || r_type == elfcpp::R_386_PC32))
1683     {
1684       symval.set_output_value(target->plt_section()->address()
1685                               + gsym->plt_offset());
1686       psymval = &symval;
1687     }
1688
1689   const Sized_relobj<32, false>* object = relinfo->object;
1690
1691   // Get the GOT offset if needed.
1692   // The GOT pointer points to the end of the GOT section.
1693   // We need to subtract the size of the GOT section to get
1694   // the actual offset to use in the relocation.
1695   bool have_got_offset = false;
1696   unsigned int got_offset = 0;
1697   switch (r_type)
1698     {
1699     case elfcpp::R_386_GOT32:
1700       if (gsym != NULL)
1701         {
1702           gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
1703           got_offset = (gsym->got_offset(GOT_TYPE_STANDARD)
1704                         - target->got_size());
1705         }
1706       else
1707         {
1708           unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1709           gold_assert(object->local_has_got_offset(r_sym, GOT_TYPE_STANDARD));
1710           got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
1711                         - target->got_size());
1712         }
1713       have_got_offset = true;
1714       break;
1715
1716     default:
1717       break;
1718     }
1719
1720   switch (r_type)
1721     {
1722     case elfcpp::R_386_NONE:
1723     case elfcpp::R_386_GNU_VTINHERIT:
1724     case elfcpp::R_386_GNU_VTENTRY:
1725       break;
1726
1727     case elfcpp::R_386_32:
1728       if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, true,
1729                                     output_section))
1730         Relocate_functions<32, false>::rel32(view, object, psymval);
1731       break;
1732
1733     case elfcpp::R_386_PC32:
1734       {
1735         int ref_flags = Symbol::NON_PIC_REF;
1736         if (gsym != NULL && gsym->type() == elfcpp::STT_FUNC)
1737           ref_flags |= Symbol::FUNCTION_CALL;
1738         if (should_apply_static_reloc(gsym, ref_flags, true, output_section))
1739           Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1740       }
1741       break;
1742
1743     case elfcpp::R_386_16:
1744       if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false,
1745                                     output_section))
1746         Relocate_functions<32, false>::rel16(view, object, psymval);
1747       break;
1748
1749     case elfcpp::R_386_PC16:
1750       {
1751         int ref_flags = Symbol::NON_PIC_REF;
1752         if (gsym != NULL && gsym->type() == elfcpp::STT_FUNC)
1753           ref_flags |= Symbol::FUNCTION_CALL;
1754         if (should_apply_static_reloc(gsym, ref_flags, false, output_section))
1755           Relocate_functions<32, false>::pcrel16(view, object, psymval, address);
1756       }
1757       break;
1758
1759     case elfcpp::R_386_8:
1760       if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false,
1761                                     output_section))
1762         Relocate_functions<32, false>::rel8(view, object, psymval);
1763       break;
1764
1765     case elfcpp::R_386_PC8:
1766       {
1767         int ref_flags = Symbol::NON_PIC_REF;
1768         if (gsym != NULL && gsym->type() == elfcpp::STT_FUNC)
1769           ref_flags |= Symbol::FUNCTION_CALL;
1770         if (should_apply_static_reloc(gsym, ref_flags, false,
1771                                       output_section))
1772           Relocate_functions<32, false>::pcrel8(view, object, psymval, address);
1773       }
1774       break;
1775
1776     case elfcpp::R_386_PLT32:
1777       gold_assert(gsym == NULL
1778                   || gsym->has_plt_offset()
1779                   || gsym->final_value_is_known()
1780                   || (gsym->is_defined()
1781                       && !gsym->is_from_dynobj()
1782                       && !gsym->is_preemptible()));
1783       Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
1784       break;
1785
1786     case elfcpp::R_386_GOT32:
1787       gold_assert(have_got_offset);
1788       Relocate_functions<32, false>::rel32(view, got_offset);
1789       break;
1790
1791     case elfcpp::R_386_GOTOFF:
1792       {
1793         elfcpp::Elf_types<32>::Elf_Addr value;
1794         value = (psymval->value(object, 0)
1795                  - target->got_plt_section()->address());
1796         Relocate_functions<32, false>::rel32(view, value);
1797       }
1798       break;
1799
1800     case elfcpp::R_386_GOTPC:
1801       {
1802         elfcpp::Elf_types<32>::Elf_Addr value;
1803         value = target->got_plt_section()->address();
1804         Relocate_functions<32, false>::pcrel32(view, value, address);
1805       }
1806       break;
1807
1808     case elfcpp::R_386_COPY:
1809     case elfcpp::R_386_GLOB_DAT:
1810     case elfcpp::R_386_JUMP_SLOT:
1811     case elfcpp::R_386_RELATIVE:
1812       // These are outstanding tls relocs, which are unexpected when
1813       // linking.
1814     case elfcpp::R_386_TLS_TPOFF:
1815     case elfcpp::R_386_TLS_DTPMOD32:
1816     case elfcpp::R_386_TLS_DTPOFF32:
1817     case elfcpp::R_386_TLS_TPOFF32:
1818     case elfcpp::R_386_TLS_DESC:
1819       gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1820                              _("unexpected reloc %u in object file"),
1821                              r_type);
1822       break;
1823
1824       // These are initial tls relocs, which are expected when
1825       // linking.
1826     case elfcpp::R_386_TLS_GD:             // Global-dynamic
1827     case elfcpp::R_386_TLS_GOTDESC:        // Global-dynamic (from ~oliva url)
1828     case elfcpp::R_386_TLS_DESC_CALL:
1829     case elfcpp::R_386_TLS_LDM:            // Local-dynamic
1830     case elfcpp::R_386_TLS_LDO_32:         // Alternate local-dynamic
1831     case elfcpp::R_386_TLS_IE:             // Initial-exec
1832     case elfcpp::R_386_TLS_IE_32:
1833     case elfcpp::R_386_TLS_GOTIE:
1834     case elfcpp::R_386_TLS_LE:             // Local-exec
1835     case elfcpp::R_386_TLS_LE_32:
1836       this->relocate_tls(relinfo, target, relnum, rel, r_type, gsym, psymval,
1837                          view, address, view_size);
1838       break;
1839
1840     case elfcpp::R_386_32PLT:
1841     case elfcpp::R_386_TLS_GD_32:
1842     case elfcpp::R_386_TLS_GD_PUSH:
1843     case elfcpp::R_386_TLS_GD_CALL:
1844     case elfcpp::R_386_TLS_GD_POP:
1845     case elfcpp::R_386_TLS_LDM_32:
1846     case elfcpp::R_386_TLS_LDM_PUSH:
1847     case elfcpp::R_386_TLS_LDM_CALL:
1848     case elfcpp::R_386_TLS_LDM_POP:
1849     case elfcpp::R_386_USED_BY_INTEL_200:
1850     default:
1851       gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1852                              _("unsupported reloc %u"),
1853                              r_type);
1854       break;
1855     }
1856
1857   return true;
1858 }
1859
1860 // Perform a TLS relocation.
1861
1862 inline void
1863 Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo,
1864                                     Target_i386* target,
1865                                     size_t relnum,
1866                                     const elfcpp::Rel<32, false>& rel,
1867                                     unsigned int r_type,
1868                                     const Sized_symbol<32>* gsym,
1869                                     const Symbol_value<32>* psymval,
1870                                     unsigned char* view,
1871                                     elfcpp::Elf_types<32>::Elf_Addr,
1872                                     section_size_type view_size)
1873 {
1874   Output_segment* tls_segment = relinfo->layout->tls_segment();
1875
1876   const Sized_relobj<32, false>* object = relinfo->object;
1877
1878   elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(object, 0);
1879
1880   const bool is_final =
1881     (gsym == NULL
1882      ? !parameters->options().output_is_position_independent()
1883      : gsym->final_value_is_known());
1884   const tls::Tls_optimization optimized_type
1885       = Target_i386::optimize_tls_reloc(is_final, r_type);
1886   switch (r_type)
1887     {
1888     case elfcpp::R_386_TLS_GD:           // Global-dynamic
1889       if (optimized_type == tls::TLSOPT_TO_LE)
1890         {
1891           gold_assert(tls_segment != NULL);
1892           this->tls_gd_to_le(relinfo, relnum, tls_segment,
1893                              rel, r_type, value, view,
1894                              view_size);
1895           break;
1896         }
1897       else
1898         {
1899           unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
1900                                    ? GOT_TYPE_TLS_NOFFSET
1901                                    : GOT_TYPE_TLS_PAIR);
1902           unsigned int got_offset;
1903           if (gsym != NULL)
1904             {
1905               gold_assert(gsym->has_got_offset(got_type));
1906               got_offset = gsym->got_offset(got_type) - target->got_size();
1907             }
1908           else
1909             {
1910               unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1911               gold_assert(object->local_has_got_offset(r_sym, got_type));
1912               got_offset = (object->local_got_offset(r_sym, got_type)
1913                             - target->got_size());
1914             }
1915           if (optimized_type == tls::TLSOPT_TO_IE)
1916             {
1917               gold_assert(tls_segment != NULL);
1918               this->tls_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type,
1919                                  got_offset, view, view_size);
1920               break;
1921             }
1922           else if (optimized_type == tls::TLSOPT_NONE)
1923             {
1924               // Relocate the field with the offset of the pair of GOT
1925               // entries.
1926               Relocate_functions<32, false>::rel32(view, got_offset);
1927               break;
1928             }
1929         }
1930       gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1931                              _("unsupported reloc %u"),
1932                              r_type);
1933       break;
1934
1935     case elfcpp::R_386_TLS_GOTDESC:      // Global-dynamic (from ~oliva url)
1936     case elfcpp::R_386_TLS_DESC_CALL:
1937       this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
1938       if (optimized_type == tls::TLSOPT_TO_LE)
1939         {
1940           gold_assert(tls_segment != NULL);
1941           this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
1942                                   rel, r_type, value, view,
1943                                   view_size);
1944           break;
1945         }
1946       else
1947         {
1948           unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
1949                                    ? GOT_TYPE_TLS_NOFFSET
1950                                    : GOT_TYPE_TLS_DESC);
1951           unsigned int got_offset;
1952           if (gsym != NULL)
1953             {
1954               gold_assert(gsym->has_got_offset(got_type));
1955               got_offset = gsym->got_offset(got_type) - target->got_size();
1956             }
1957           else
1958             {
1959               unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
1960               gold_assert(object->local_has_got_offset(r_sym, got_type));
1961               got_offset = (object->local_got_offset(r_sym, got_type)
1962                             - target->got_size());
1963             }
1964           if (optimized_type == tls::TLSOPT_TO_IE)
1965             {
1966               gold_assert(tls_segment != NULL);
1967               this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment, rel, r_type,
1968                                       got_offset, view, view_size);
1969               break;
1970             }
1971           else if (optimized_type == tls::TLSOPT_NONE)
1972             {
1973               if (r_type == elfcpp::R_386_TLS_GOTDESC)
1974                 {
1975                   // Relocate the field with the offset of the pair of GOT
1976                   // entries.
1977                   Relocate_functions<32, false>::rel32(view, got_offset);
1978                 }
1979               break;
1980             }
1981         }
1982       gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1983                              _("unsupported reloc %u"),
1984                              r_type);
1985       break;
1986
1987     case elfcpp::R_386_TLS_LDM:          // Local-dynamic
1988       if (this->local_dynamic_type_ == LOCAL_DYNAMIC_SUN)
1989         {
1990           gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
1991                                  _("both SUN and GNU model "
1992                                    "TLS relocations"));
1993           break;
1994         }
1995       this->local_dynamic_type_ = LOCAL_DYNAMIC_GNU;
1996       if (optimized_type == tls::TLSOPT_TO_LE)
1997         {
1998           gold_assert(tls_segment != NULL);
1999           this->tls_ld_to_le(relinfo, relnum, tls_segment, rel, r_type,
2000                              value, view, view_size);
2001           break;
2002         }
2003       else if (optimized_type == tls::TLSOPT_NONE)
2004         {
2005           // Relocate the field with the offset of the GOT entry for
2006           // the module index.
2007           unsigned int got_offset;
2008           got_offset = (target->got_mod_index_entry(NULL, NULL, NULL)
2009                         - target->got_size());
2010           Relocate_functions<32, false>::rel32(view, got_offset);
2011           break;
2012         }
2013       gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2014                              _("unsupported reloc %u"),
2015                              r_type);
2016       break;
2017
2018     case elfcpp::R_386_TLS_LDO_32:       // Alternate local-dynamic
2019       if (optimized_type == tls::TLSOPT_TO_LE)
2020         {
2021           // This reloc can appear in debugging sections, in which
2022           // case we must not convert to local-exec.  We decide what
2023           // to do based on whether the section is marked as
2024           // containing executable code.  That is what the GNU linker
2025           // does as well.
2026           elfcpp::Shdr<32, false> shdr(relinfo->data_shdr);
2027           if ((shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0)
2028             {
2029               gold_assert(tls_segment != NULL);
2030               value -= tls_segment->memsz();
2031             }
2032         }
2033       Relocate_functions<32, false>::rel32(view, value);
2034       break;
2035
2036     case elfcpp::R_386_TLS_IE:           // Initial-exec
2037     case elfcpp::R_386_TLS_GOTIE:
2038     case elfcpp::R_386_TLS_IE_32:
2039       if (optimized_type == tls::TLSOPT_TO_LE)
2040         {
2041           gold_assert(tls_segment != NULL);
2042           Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
2043                                               rel, r_type, value, view,
2044                                               view_size);
2045           break;
2046         }
2047       else if (optimized_type == tls::TLSOPT_NONE)
2048         {
2049           // Relocate the field with the offset of the GOT entry for
2050           // the tp-relative offset of the symbol.
2051           unsigned int got_type = (r_type == elfcpp::R_386_TLS_IE_32
2052                                    ? GOT_TYPE_TLS_OFFSET
2053                                    : GOT_TYPE_TLS_NOFFSET);
2054           unsigned int got_offset;
2055           if (gsym != NULL)
2056             {
2057               gold_assert(gsym->has_got_offset(got_type));
2058               got_offset = gsym->got_offset(got_type);
2059             }
2060           else
2061             {
2062               unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
2063               gold_assert(object->local_has_got_offset(r_sym, got_type));
2064               got_offset = object->local_got_offset(r_sym, got_type);
2065             }
2066           // For the R_386_TLS_IE relocation, we need to apply the
2067           // absolute address of the GOT entry.
2068           if (r_type == elfcpp::R_386_TLS_IE)
2069             got_offset += target->got_plt_section()->address();
2070           // All GOT offsets are relative to the end of the GOT.
2071           got_offset -= target->got_size();
2072           Relocate_functions<32, false>::rel32(view, got_offset);
2073           break;
2074         }
2075       gold_error_at_location(relinfo, relnum, rel.get_r_offset(),
2076                              _("unsupported reloc %u"),
2077                              r_type);
2078       break;
2079
2080     case elfcpp::R_386_TLS_LE:           // Local-exec
2081       // If we're creating a shared library, a dynamic relocation will
2082       // have been created for this location, so do not apply it now.
2083       if (!parameters->options().shared())
2084         {
2085           gold_assert(tls_segment != NULL);
2086           value -= tls_segment->memsz();
2087           Relocate_functions<32, false>::rel32(view, value);
2088         }
2089       break;
2090
2091     case elfcpp::R_386_TLS_LE_32:
2092       // If we're creating a shared library, a dynamic relocation will
2093       // have been created for this location, so do not apply it now.
2094       if (!parameters->options().shared())
2095         {
2096           gold_assert(tls_segment != NULL);
2097           value = tls_segment->memsz() - value;
2098           Relocate_functions<32, false>::rel32(view, value);
2099         }
2100       break;
2101     }
2102 }
2103
2104 // Do a relocation in which we convert a TLS General-Dynamic to a
2105 // Local-Exec.
2106
2107 inline void
2108 Target_i386::Relocate::tls_gd_to_le(const Relocate_info<32, false>* relinfo,
2109                                     size_t relnum,
2110                                     Output_segment* tls_segment,
2111                                     const elfcpp::Rel<32, false>& rel,
2112                                     unsigned int,
2113                                     elfcpp::Elf_types<32>::Elf_Addr value,
2114                                     unsigned char* view,
2115                                     section_size_type view_size)
2116 {
2117   // leal foo(,%reg,1),%eax; call ___tls_get_addr
2118   //  ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
2119   // leal foo(%reg),%eax; call ___tls_get_addr
2120   //  ==> movl %gs:0,%eax; subl $foo@tpoff,%eax
2121
2122   tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2123   tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
2124
2125   unsigned char op1 = view[-1];
2126   unsigned char op2 = view[-2];
2127
2128   tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2129                  op2 == 0x8d || op2 == 0x04);
2130   tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
2131
2132   int roff = 5;
2133
2134   if (op2 == 0x04)
2135     {
2136       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
2137       tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
2138       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2139                      ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
2140       memcpy(view - 3, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
2141     }
2142   else
2143     {
2144       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2145                      (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
2146       if (rel.get_r_offset() + 9 < view_size
2147           && view[9] == 0x90)
2148         {
2149           // There is a trailing nop.  Use the size byte subl.
2150           memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
2151           roff = 6;
2152         }
2153       else
2154         {
2155           // Use the five byte subl.
2156           memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
2157         }
2158     }
2159
2160   value = tls_segment->memsz() - value;
2161   Relocate_functions<32, false>::rel32(view + roff, value);
2162
2163   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2164   // We can skip it.
2165   this->skip_call_tls_get_addr_ = true;
2166 }
2167
2168 // Do a relocation in which we convert a TLS General-Dynamic to an
2169 // Initial-Exec.
2170
2171 inline void
2172 Target_i386::Relocate::tls_gd_to_ie(const Relocate_info<32, false>* relinfo,
2173                                     size_t relnum,
2174                                     Output_segment*,
2175                                     const elfcpp::Rel<32, false>& rel,
2176                                     unsigned int,
2177                                     elfcpp::Elf_types<32>::Elf_Addr value,
2178                                     unsigned char* view,
2179                                     section_size_type view_size)
2180 {
2181   // leal foo(,%ebx,1),%eax; call ___tls_get_addr
2182   //  ==> movl %gs:0,%eax; addl foo@gotntpoff(%ebx),%eax
2183
2184   tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2185   tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
2186
2187   unsigned char op1 = view[-1];
2188   unsigned char op2 = view[-2];
2189
2190   tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2191                  op2 == 0x8d || op2 == 0x04);
2192   tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
2193
2194   int roff = 5;
2195
2196   // FIXME: For now, support only the first (SIB) form.
2197   tls::check_tls(relinfo, relnum, rel.get_r_offset(), op2 == 0x04);
2198
2199   if (op2 == 0x04)
2200     {
2201       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -3);
2202       tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
2203       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2204                      ((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
2205       memcpy(view - 3, "\x65\xa1\0\0\0\0\x03\x83\0\0\0", 12);
2206     }
2207   else
2208     {
2209       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2210                      (op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
2211       if (rel.get_r_offset() + 9 < view_size
2212           && view[9] == 0x90)
2213         {
2214           // FIXME: This is not the right instruction sequence.
2215           // There is a trailing nop.  Use the size byte subl.
2216           memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
2217           roff = 6;
2218         }
2219       else
2220         {
2221           // FIXME: This is not the right instruction sequence.
2222           // Use the five byte subl.
2223           memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
2224         }
2225     }
2226
2227   Relocate_functions<32, false>::rel32(view + roff, value);
2228
2229   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2230   // We can skip it.
2231   this->skip_call_tls_get_addr_ = true;
2232 }
2233
2234 // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL
2235 // General-Dynamic to a Local-Exec.
2236
2237 inline void
2238 Target_i386::Relocate::tls_desc_gd_to_le(
2239     const Relocate_info<32, false>* relinfo,
2240     size_t relnum,
2241     Output_segment* tls_segment,
2242     const elfcpp::Rel<32, false>& rel,
2243     unsigned int r_type,
2244     elfcpp::Elf_types<32>::Elf_Addr value,
2245     unsigned char* view,
2246     section_size_type view_size)
2247 {
2248   if (r_type == elfcpp::R_386_TLS_GOTDESC)
2249     {
2250       // leal foo@TLSDESC(%ebx), %eax
2251       // ==> leal foo@NTPOFF, %eax
2252       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2253       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2254       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2255                      view[-2] == 0x8d && view[-1] == 0x83);
2256       view[-1] = 0x05;
2257       value -= tls_segment->memsz();
2258       Relocate_functions<32, false>::rel32(view, value);
2259     }
2260   else
2261     {
2262       // call *foo@TLSCALL(%eax)
2263       // ==> nop; nop
2264       gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL);
2265       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2);
2266       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2267                      view[0] == 0xff && view[1] == 0x10);
2268       view[0] = 0x66;
2269       view[1] = 0x90;
2270     }
2271 }
2272
2273 // Do a relocation in which we convert a TLS_GOTDESC or TLS_DESC_CALL
2274 // General-Dynamic to an Initial-Exec.
2275
2276 inline void
2277 Target_i386::Relocate::tls_desc_gd_to_ie(
2278     const Relocate_info<32, false>* relinfo,
2279     size_t relnum,
2280     Output_segment*,
2281     const elfcpp::Rel<32, false>& rel,
2282     unsigned int r_type,
2283     elfcpp::Elf_types<32>::Elf_Addr value,
2284     unsigned char* view,
2285     section_size_type view_size)
2286 {
2287   if (r_type == elfcpp::R_386_TLS_GOTDESC)
2288     {
2289       // leal foo@TLSDESC(%ebx), %eax
2290       // ==> movl foo@GOTNTPOFF(%ebx), %eax
2291       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2292       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2293       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2294                      view[-2] == 0x8d && view[-1] == 0x83);
2295       view[-2] = 0x8b;
2296       Relocate_functions<32, false>::rel32(view, value);
2297     }
2298   else
2299     {
2300       // call *foo@TLSCALL(%eax)
2301       // ==> nop; nop
2302       gold_assert(r_type == elfcpp::R_386_TLS_DESC_CALL);
2303       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 2);
2304       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2305                      view[0] == 0xff && view[1] == 0x10);
2306       view[0] = 0x66;
2307       view[1] = 0x90;
2308     }
2309 }
2310
2311 // Do a relocation in which we convert a TLS Local-Dynamic to a
2312 // Local-Exec.
2313
2314 inline void
2315 Target_i386::Relocate::tls_ld_to_le(const Relocate_info<32, false>* relinfo,
2316                                     size_t relnum,
2317                                     Output_segment*,
2318                                     const elfcpp::Rel<32, false>& rel,
2319                                     unsigned int,
2320                                     elfcpp::Elf_types<32>::Elf_Addr,
2321                                     unsigned char* view,
2322                                     section_size_type view_size)
2323 {
2324   // leal foo(%reg), %eax; call ___tls_get_addr
2325   // ==> movl %gs:0,%eax; nop; leal 0(%esi,1),%esi
2326
2327   tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2328   tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
2329
2330   // FIXME: Does this test really always pass?
2331   tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2332                  view[-2] == 0x8d && view[-1] == 0x83);
2333
2334   tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
2335
2336   memcpy(view - 2, "\x65\xa1\0\0\0\0\x90\x8d\x74\x26\0", 11);
2337
2338   // The next reloc should be a PLT32 reloc against __tls_get_addr.
2339   // We can skip it.
2340   this->skip_call_tls_get_addr_ = true;
2341 }
2342
2343 // Do a relocation in which we convert a TLS Initial-Exec to a
2344 // Local-Exec.
2345
2346 inline void
2347 Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo,
2348                                     size_t relnum,
2349                                     Output_segment* tls_segment,
2350                                     const elfcpp::Rel<32, false>& rel,
2351                                     unsigned int r_type,
2352                                     elfcpp::Elf_types<32>::Elf_Addr value,
2353                                     unsigned char* view,
2354                                     section_size_type view_size)
2355 {
2356   // We have to actually change the instructions, which means that we
2357   // need to examine the opcodes to figure out which instruction we
2358   // are looking at.
2359   if (r_type == elfcpp::R_386_TLS_IE)
2360     {
2361       // movl %gs:XX,%eax  ==>  movl $YY,%eax
2362       // movl %gs:XX,%reg  ==>  movl $YY,%reg
2363       // addl %gs:XX,%reg  ==>  addl $YY,%reg
2364       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -1);
2365       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2366
2367       unsigned char op1 = view[-1];
2368       if (op1 == 0xa1)
2369         {
2370           // movl XX,%eax  ==>  movl $YY,%eax
2371           view[-1] = 0xb8;
2372         }
2373       else
2374         {
2375           tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2376
2377           unsigned char op2 = view[-2];
2378           if (op2 == 0x8b)
2379             {
2380               // movl XX,%reg  ==>  movl $YY,%reg
2381               tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2382                              (op1 & 0xc7) == 0x05);
2383               view[-2] = 0xc7;
2384               view[-1] = 0xc0 | ((op1 >> 3) & 7);
2385             }
2386           else if (op2 == 0x03)
2387             {
2388               // addl XX,%reg  ==>  addl $YY,%reg
2389               tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2390                              (op1 & 0xc7) == 0x05);
2391               view[-2] = 0x81;
2392               view[-1] = 0xc0 | ((op1 >> 3) & 7);
2393             }
2394           else
2395             tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
2396         }
2397     }
2398   else
2399     {
2400       // subl %gs:XX(%reg1),%reg2  ==>  subl $YY,%reg2
2401       // movl %gs:XX(%reg1),%reg2  ==>  movl $YY,%reg2
2402       // addl %gs:XX(%reg1),%reg2  ==>  addl $YY,$reg2
2403       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
2404       tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 4);
2405
2406       unsigned char op1 = view[-1];
2407       unsigned char op2 = view[-2];
2408       tls::check_tls(relinfo, relnum, rel.get_r_offset(),
2409                      (op1 & 0xc0) == 0x80 && (op1 & 7) != 4);
2410       if (op2 == 0x8b)
2411         {
2412           // movl %gs:XX(%reg1),%reg2  ==>  movl $YY,%reg2
2413           view[-2] = 0xc7;
2414           view[-1] = 0xc0 | ((op1 >> 3) & 7);
2415         }
2416       else if (op2 == 0x2b)
2417         {
2418           // subl %gs:XX(%reg1),%reg2  ==>  subl $YY,%reg2
2419           view[-2] = 0x81;
2420           view[-1] = 0xe8 | ((op1 >> 3) & 7);
2421         }
2422       else if (op2 == 0x03)
2423         {
2424           // addl %gs:XX(%reg1),%reg2  ==>  addl $YY,$reg2
2425           view[-2] = 0x81;
2426           view[-1] = 0xc0 | ((op1 >> 3) & 7);
2427         }
2428       else
2429         tls::check_tls(relinfo, relnum, rel.get_r_offset(), 0);
2430     }
2431
2432   value = tls_segment->memsz() - value;
2433   if (r_type == elfcpp::R_386_TLS_IE || r_type == elfcpp::R_386_TLS_GOTIE)
2434     value = - value;
2435
2436   Relocate_functions<32, false>::rel32(view, value);
2437 }
2438
2439 // Relocate section data.
2440
2441 void
2442 Target_i386::relocate_section(const Relocate_info<32, false>* relinfo,
2443                               unsigned int sh_type,
2444                               const unsigned char* prelocs,
2445                               size_t reloc_count,
2446                               Output_section* output_section,
2447                               bool needs_special_offset_handling,
2448                               unsigned char* view,
2449                               elfcpp::Elf_types<32>::Elf_Addr address,
2450                               section_size_type view_size,
2451                               const Reloc_symbol_changes* reloc_symbol_changes)
2452 {
2453   gold_assert(sh_type == elfcpp::SHT_REL);
2454
2455   gold::relocate_section<32, false, Target_i386, elfcpp::SHT_REL,
2456                          Target_i386::Relocate>(
2457     relinfo,
2458     this,
2459     prelocs,
2460     reloc_count,
2461     output_section,
2462     needs_special_offset_handling,
2463     view,
2464     address,
2465     view_size,
2466     reloc_symbol_changes);
2467 }
2468
2469 // Return the size of a relocation while scanning during a relocatable
2470 // link.
2471
2472 unsigned int
2473 Target_i386::Relocatable_size_for_reloc::get_size_for_reloc(
2474     unsigned int r_type,
2475     Relobj* object)
2476 {
2477   switch (r_type)
2478     {
2479     case elfcpp::R_386_NONE:
2480     case elfcpp::R_386_GNU_VTINHERIT:
2481     case elfcpp::R_386_GNU_VTENTRY:
2482     case elfcpp::R_386_TLS_GD:            // Global-dynamic
2483     case elfcpp::R_386_TLS_GOTDESC:       // Global-dynamic (from ~oliva url)
2484     case elfcpp::R_386_TLS_DESC_CALL:
2485     case elfcpp::R_386_TLS_LDM:           // Local-dynamic
2486     case elfcpp::R_386_TLS_LDO_32:        // Alternate local-dynamic
2487     case elfcpp::R_386_TLS_IE:            // Initial-exec
2488     case elfcpp::R_386_TLS_IE_32:
2489     case elfcpp::R_386_TLS_GOTIE:
2490     case elfcpp::R_386_TLS_LE:            // Local-exec
2491     case elfcpp::R_386_TLS_LE_32:
2492       return 0;
2493
2494     case elfcpp::R_386_32:
2495     case elfcpp::R_386_PC32:
2496     case elfcpp::R_386_GOT32:
2497     case elfcpp::R_386_PLT32:
2498     case elfcpp::R_386_GOTOFF:
2499     case elfcpp::R_386_GOTPC:
2500      return 4;
2501
2502     case elfcpp::R_386_16:
2503     case elfcpp::R_386_PC16:
2504       return 2;
2505
2506     case elfcpp::R_386_8:
2507     case elfcpp::R_386_PC8:
2508       return 1;
2509
2510       // These are relocations which should only be seen by the
2511       // dynamic linker, and should never be seen here.
2512     case elfcpp::R_386_COPY:
2513     case elfcpp::R_386_GLOB_DAT:
2514     case elfcpp::R_386_JUMP_SLOT:
2515     case elfcpp::R_386_RELATIVE:
2516     case elfcpp::R_386_TLS_TPOFF:
2517     case elfcpp::R_386_TLS_DTPMOD32:
2518     case elfcpp::R_386_TLS_DTPOFF32:
2519     case elfcpp::R_386_TLS_TPOFF32:
2520     case elfcpp::R_386_TLS_DESC:
2521       object->error(_("unexpected reloc %u in object file"), r_type);
2522       return 0;
2523
2524     case elfcpp::R_386_32PLT:
2525     case elfcpp::R_386_TLS_GD_32:
2526     case elfcpp::R_386_TLS_GD_PUSH:
2527     case elfcpp::R_386_TLS_GD_CALL:
2528     case elfcpp::R_386_TLS_GD_POP:
2529     case elfcpp::R_386_TLS_LDM_32:
2530     case elfcpp::R_386_TLS_LDM_PUSH:
2531     case elfcpp::R_386_TLS_LDM_CALL:
2532     case elfcpp::R_386_TLS_LDM_POP:
2533     case elfcpp::R_386_USED_BY_INTEL_200:
2534     default:
2535       object->error(_("unsupported reloc %u in object file"), r_type);
2536       return 0;
2537     }
2538 }
2539
2540 // Scan the relocs during a relocatable link.
2541
2542 void
2543 Target_i386::scan_relocatable_relocs(const General_options& options,
2544                                      Symbol_table* symtab,
2545                                      Layout* layout,
2546                                      Sized_relobj<32, false>* object,
2547                                      unsigned int data_shndx,
2548                                      unsigned int sh_type,
2549                                      const unsigned char* prelocs,
2550                                      size_t reloc_count,
2551                                      Output_section* output_section,
2552                                      bool needs_special_offset_handling,
2553                                      size_t local_symbol_count,
2554                                      const unsigned char* plocal_symbols,
2555                                      Relocatable_relocs* rr)
2556 {
2557   gold_assert(sh_type == elfcpp::SHT_REL);
2558
2559   typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_REL,
2560     Relocatable_size_for_reloc> Scan_relocatable_relocs;
2561
2562   gold::scan_relocatable_relocs<32, false, elfcpp::SHT_REL,
2563       Scan_relocatable_relocs>(
2564     options,
2565     symtab,
2566     layout,
2567     object,
2568     data_shndx,
2569     prelocs,
2570     reloc_count,
2571     output_section,
2572     needs_special_offset_handling,
2573     local_symbol_count,
2574     plocal_symbols,
2575     rr);
2576 }
2577
2578 // Relocate a section during a relocatable link.
2579
2580 void
2581 Target_i386::relocate_for_relocatable(
2582     const Relocate_info<32, false>* relinfo,
2583     unsigned int sh_type,
2584     const unsigned char* prelocs,
2585     size_t reloc_count,
2586     Output_section* output_section,
2587     off_t offset_in_output_section,
2588     const Relocatable_relocs* rr,
2589     unsigned char* view,
2590     elfcpp::Elf_types<32>::Elf_Addr view_address,
2591     section_size_type view_size,
2592     unsigned char* reloc_view,
2593     section_size_type reloc_view_size)
2594 {
2595   gold_assert(sh_type == elfcpp::SHT_REL);
2596
2597   gold::relocate_for_relocatable<32, false, elfcpp::SHT_REL>(
2598     relinfo,
2599     prelocs,
2600     reloc_count,
2601     output_section,
2602     offset_in_output_section,
2603     rr,
2604     view,
2605     view_address,
2606     view_size,
2607     reloc_view,
2608     reloc_view_size);
2609 }
2610
2611 // Return the value to use for a dynamic which requires special
2612 // treatment.  This is how we support equality comparisons of function
2613 // pointers across shared library boundaries, as described in the
2614 // processor specific ABI supplement.
2615
2616 uint64_t
2617 Target_i386::do_dynsym_value(const Symbol* gsym) const
2618 {
2619   gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
2620   return this->plt_section()->address() + gsym->plt_offset();
2621 }
2622
2623 // Return a string used to fill a code section with nops to take up
2624 // the specified length.
2625
2626 std::string
2627 Target_i386::do_code_fill(section_size_type length) const
2628 {
2629   if (length >= 16)
2630     {
2631       // Build a jmp instruction to skip over the bytes.
2632       unsigned char jmp[5];
2633       jmp[0] = 0xe9;
2634       elfcpp::Swap_unaligned<32, false>::writeval(jmp + 1, length - 5);
2635       return (std::string(reinterpret_cast<char*>(&jmp[0]), 5)
2636               + std::string(length - 5, '\0'));
2637     }
2638
2639   // Nop sequences of various lengths.
2640   const char nop1[1] = { 0x90 };                   // nop
2641   const char nop2[2] = { 0x66, 0x90 };             // xchg %ax %ax
2642   const char nop3[3] = { 0x8d, 0x76, 0x00 };       // leal 0(%esi),%esi
2643   const char nop4[4] = { 0x8d, 0x74, 0x26, 0x00};  // leal 0(%esi,1),%esi
2644   const char nop5[5] = { 0x90, 0x8d, 0x74, 0x26,   // nop
2645                          0x00 };                   // leal 0(%esi,1),%esi
2646   const char nop6[6] = { 0x8d, 0xb6, 0x00, 0x00,   // leal 0L(%esi),%esi
2647                          0x00, 0x00 };
2648   const char nop7[7] = { 0x8d, 0xb4, 0x26, 0x00,   // leal 0L(%esi,1),%esi
2649                          0x00, 0x00, 0x00 };
2650   const char nop8[8] = { 0x90, 0x8d, 0xb4, 0x26,   // nop
2651                          0x00, 0x00, 0x00, 0x00 }; // leal 0L(%esi,1),%esi
2652   const char nop9[9] = { 0x89, 0xf6, 0x8d, 0xbc,   // movl %esi,%esi
2653                          0x27, 0x00, 0x00, 0x00,   // leal 0L(%edi,1),%edi
2654                          0x00 };
2655   const char nop10[10] = { 0x8d, 0x76, 0x00, 0x8d, // leal 0(%esi),%esi
2656                            0xbc, 0x27, 0x00, 0x00, // leal 0L(%edi,1),%edi
2657                            0x00, 0x00 };
2658   const char nop11[11] = { 0x8d, 0x74, 0x26, 0x00, // leal 0(%esi,1),%esi
2659                            0x8d, 0xbc, 0x27, 0x00, // leal 0L(%edi,1),%edi
2660                            0x00, 0x00, 0x00 };
2661   const char nop12[12] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2662                            0x00, 0x00, 0x8d, 0xbf, // leal 0L(%edi),%edi
2663                            0x00, 0x00, 0x00, 0x00 };
2664   const char nop13[13] = { 0x8d, 0xb6, 0x00, 0x00, // leal 0L(%esi),%esi
2665                            0x00, 0x00, 0x8d, 0xbc, // leal 0L(%edi,1),%edi
2666                            0x27, 0x00, 0x00, 0x00,
2667                            0x00 };
2668   const char nop14[14] = { 0x8d, 0xb4, 0x26, 0x00, // leal 0L(%esi,1),%esi
2669                            0x00, 0x00, 0x00, 0x8d, // leal 0L(%edi,1),%edi
2670                            0xbc, 0x27, 0x00, 0x00,
2671                            0x00, 0x00 };
2672   const char nop15[15] = { 0xeb, 0x0d, 0x90, 0x90, // jmp .+15
2673                            0x90, 0x90, 0x90, 0x90, // nop,nop,nop,...
2674                            0x90, 0x90, 0x90, 0x90,
2675                            0x90, 0x90, 0x90 };
2676
2677   const char* nops[16] = {
2678     NULL,
2679     nop1, nop2, nop3, nop4, nop5, nop6, nop7,
2680     nop8, nop9, nop10, nop11, nop12, nop13, nop14, nop15
2681   };
2682
2683   return std::string(nops[length], length);
2684 }
2685
2686 // FNOFFSET in section SHNDX in OBJECT is the start of a function
2687 // compiled with -fstack-split.  The function calls non-stack-split
2688 // code.  We have to change the function so that it always ensures
2689 // that it has enough stack space to run some random function.
2690
2691 void
2692 Target_i386::do_calls_non_split(Relobj* object, unsigned int shndx,
2693                                 section_offset_type fnoffset,
2694                                 section_size_type fnsize,
2695                                 unsigned char* view,
2696                                 section_size_type view_size,
2697                                 std::string* from,
2698                                 std::string* to) const
2699 {
2700   // The function starts with a comparison of the stack pointer and a
2701   // field in the TCB.  This is followed by a jump.
2702
2703   // cmp %gs:NN,%esp
2704   if (this->match_view(view, view_size, fnoffset, "\x65\x3b\x25", 3)
2705       && fnsize > 7)
2706     {
2707       // We will call __morestack if the carry flag is set after this
2708       // comparison.  We turn the comparison into an stc instruction
2709       // and some nops.
2710       view[fnoffset] = '\xf9';
2711       this->set_view_to_nop(view, view_size, fnoffset + 1, 6);
2712     }
2713   // lea NN(%esp),%ecx
2714   else if (this->match_view(view, view_size, fnoffset, "\x8d\x8c\x24", 3)
2715            && fnsize > 7)
2716     {
2717       // This is loading an offset from the stack pointer for a
2718       // comparison.  The offset is negative, so we decrease the
2719       // offset by the amount of space we need for the stack.  This
2720       // means we will avoid calling __morestack if there happens to
2721       // be plenty of space on the stack already.
2722       unsigned char* pval = view + fnoffset + 3;
2723       uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval);
2724       val -= parameters->options().split_stack_adjust_size();
2725       elfcpp::Swap_unaligned<32, false>::writeval(pval, val);
2726     }
2727   else
2728     {
2729       if (!object->has_no_split_stack())
2730         object->error(_("failed to match split-stack sequence at "
2731                         "section %u offset %0zx"),
2732                       shndx, fnoffset);
2733       return;
2734     }
2735
2736   // We have to change the function so that it calls
2737   // __morestack_non_split instead of __morestack.  The former will
2738   // allocate additional stack space.
2739   *from = "__morestack";
2740   *to = "__morestack_non_split";
2741 }
2742
2743 // The selector for i386 object files.
2744
2745 class Target_selector_i386 : public Target_selector_freebsd
2746 {
2747 public:
2748   Target_selector_i386()
2749     : Target_selector_freebsd(elfcpp::EM_386, 32, false,
2750                               "elf32-i386", "elf32-i386-freebsd")
2751   { }
2752
2753   Target*
2754   do_instantiate_target()
2755   { return new Target_i386(); }
2756 };
2757
2758 Target_selector_i386 target_selector_i386;
2759
2760 } // End anonymous namespace.