gold/i386.cc

   1 // i386.cc -- i386 target support for gold.
   2
   3 #include "gold.h"
   4 #include "elfcpp.h"
   5 #include "reloc.h"
   6 #include "i386.h"
   7 #include "object.h"
   8 #include "layout.h"
   9 #include "output.h"
  10 #include "target.h"
  11 #include "target-reloc.h"
  12 #include "target-select.h"
  13
  14 namespace
  15 {
  16
  17 using namespace gold;
  18
  19 // The i386 target class.
  20
  21 class Target_i386 : public Sized_target<32, false>
  22 {
  23  public:
  24   Target_i386()
  25     : Sized_target<32, false>(&i386_info)
  26   { }
  27
  28   // Scan the relocations to look for symbol adjustments.
  29   void
  30   scan_relocs(const General_options& options,
  31               Symbol_table* symtab,
  32               Sized_object<32, false>* object,
  33               unsigned int sh_type,
  34               const unsigned char* prelocs,
  35               size_t reloc_count,
  36               size_t local_symbol_count,
  37               const unsigned char* plocal_symbols,
  38               Symbol** global_symbols);
  39
  40   // Relocate a section.
  41   void
  42   relocate_section(const Relocate_info<32, false>*,
  43                    unsigned int sh_type,
  44                    const unsigned char* prelocs,
  45                    size_t reloc_count,
  46                    unsigned char* view,
  47                    elfcpp::Elf_types<32>::Elf_Addr view_address,
  48                    off_t view_size);
  49
  50  private:
  51   // The class which scans relocations.
  52   struct Scan
  53   {
  54     inline void
  55     local(const General_options& options, Sized_object<32, false>* object,
  56           const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
  57           const elfcpp::Sym<32, false>& lsym);
  58
  59     inline void
  60     global(const General_options& options, Sized_object<32, false>* object,
  61            const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
  62            Symbol* gsym);
  63   };
  64
  65   // The class which implements relocation.
  66   class Relocate
  67   {
  68    public:
  69     // Do a relocation.
  70     static inline void
  71     relocate(const Relocate_info<32, false>*, size_t relnum,
  72              const elfcpp::Rel<32, false>&,
  73              unsigned int r_type, Sized_symbol<32>*,
  74              elfcpp::Elf_types<32>::Elf_Addr,
  75              unsigned char*, elfcpp::Elf_types<32>::Elf_Addr,
  76              off_t);
  77
  78    private:
  79     // Do a TLS relocation.
  80     static inline void
  81     relocate_tls(const Relocate_info<32, false>*, size_t relnum,
  82                  const elfcpp::Rel<32, false>&,
  83                  unsigned int r_type, Sized_symbol<32>*,
  84                  elfcpp::Elf_types<32>::Elf_Addr,
  85                  unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, off_t);
  86
  87     // Do a TLS Initial-Exec to Local-Exec transition.
  88     static inline void
  89     tls_ie_to_le(const Relocate_info<32, false>*, size_t relnum,
  90                  Output_segment* tls_segment,
  91                  const elfcpp::Rel<32, false>&, unsigned int r_type,
  92                  elfcpp::Elf_types<32>::Elf_Addr value,
  93                  unsigned char* view,
  94                  off_t view_size);
  95
  96     // Check the range for a TLS relocation.
  97     static inline void
  98     check_range(const Relocate_info<32, false>*, size_t relnum,
  99                 const elfcpp::Rel<32, false>&, off_t, off_t);
 100
 101     // Check the validity of a TLS relocation.  This is like assert.
 102     static inline void
 103     check_tls(const Relocate_info<32, false>*, size_t relnum,
 104               const elfcpp::Rel<32, false>&, bool);
 105   };
 106
 107   // Adjust TLS relocation type based on the options and whether this
 108   // is a local symbol.
 109   static unsigned int
 110   optimize_tls_reloc(const General_options*, bool is_local, int r_type);
 111
 112   // Information about this specific target which we pass to the
 113   // general Target structure.
 114   static const Target::Target_info i386_info;
 115 };
 116
 117 const Target::Target_info Target_i386::i386_info =
 118 {
 119   32,                   // size
 120   false,                // is_big_endian
 121   elfcpp::EM_386,       // machine_code
 122   false,                // has_make_symbol
 123   false,                // has_resolve,
 124   0x08048000,           // text_segment_address,
 125   0x1000,               // abi_pagesize
 126   0x1000                // common_pagesize
 127 };
 128
 129 // Optimize the TLS relocation type based on what we know about the
 130 // symbol.  IS_LOCAL is true if this symbol can be resolved entirely
 131 // locally--i.e., does not have to be in the dynamic symbol table.
 132
 133 unsigned int
 134 Target_i386::optimize_tls_reloc(const General_options* options, bool is_local,
 135                                 int r_type)
 136 {
 137   // If we are generating a shared library, then we can't do anything
 138   // in the linker.
 139   if (options->is_shared())
 140     return r_type;
 141
 142   switch (r_type)
 143     {
 144     case elfcpp::R_386_TLS_GD:
 145     case elfcpp::R_386_TLS_GOTDESC:
 146     case elfcpp::R_386_TLS_DESC_CALL:
 147       // These are Global-Dynamic which permits fully general TLS
 148       // access.  Since we know that we are generating an executable,
 149       // we can convert this to Initial-Exec.  If we also know that
 150       // this is a local symbol, we can further switch to Local-Exec.
 151       if (is_local)
 152         return elfcpp::R_386_TLS_LE_32;
 153       return elfcpp::R_386_TLS_IE_32;
 154
 155     case elfcpp::R_386_TLS_LDM:
 156       // This is Local-Dynamic, which refers to a local symbol in the
 157       // dynamic TLS block.  Since we know that we generating an
 158       // executable, we can switch to Local-Exec.
 159       return elfcpp::R_386_TLS_LE_32;
 160
 161     case elfcpp::R_386_TLS_LDO_32:
 162       // Another type of Local-Dynamic relocation.
 163       return elfcpp::R_386_TLS_LE;
 164
 165     case elfcpp::R_386_TLS_IE:
 166     case elfcpp::R_386_TLS_GOTIE:
 167     case elfcpp::R_386_TLS_IE_32:
 168       // These are Initial-Exec relocs which get the thread offset
 169       // from the GOT.  If we know that we are linking against the
 170       // local symbol, we can switch to Local-Exec, which links the
 171       // thread offset into the instruction.
 172       if (is_local)
 173         return elfcpp::R_386_TLS_LE_32;
 174       return r_type;
 175
 176     case elfcpp::R_386_TLS_LE:
 177     case elfcpp::R_386_TLS_LE_32:
 178       // When we already have Local-Exec, there is nothing further we
 179       // can do.
 180       return r_type;
 181
 182     default:
 183       abort();
 184     }
 185 }
 186
 187 // Scan a relocation for a local symbol.
 188
 189 inline void
 190 Target_i386::Scan::local(const General_options& options,
 191                          Sized_object<32, false>* object,
 192                          const elfcpp::Rel<32, false>&, unsigned int r_type,
 193                          const elfcpp::Sym<32, false>&)
 194 {
 195   switch (r_type)
 196     {
 197     case elfcpp::R_386_NONE:
 198     case elfcpp::R_386_GNU_VTINHERIT:
 199     case elfcpp::R_386_GNU_VTENTRY:
 200       break;
 201
 202     case elfcpp::R_386_32:
 203     case elfcpp::R_386_16:
 204     case elfcpp::R_386_8:
 205       // FIXME: If we are generating a shared object we need to copy
 206       // this relocation into the object.
 207       break;
 208
 209     case elfcpp::R_386_PC32:
 210     case elfcpp::R_386_PC16:
 211     case elfcpp::R_386_PC8:
 212       break;
 213
 214     case elfcpp::R_386_COPY:
 215     case elfcpp::R_386_GLOB_DAT:
 216     case elfcpp::R_386_JUMP_SLOT:
 217     case elfcpp::R_386_RELATIVE:
 218     case elfcpp::R_386_TLS_TPOFF:
 219     case elfcpp::R_386_TLS_DTPMOD32:
 220     case elfcpp::R_386_TLS_DTPOFF32:
 221     case elfcpp::R_386_TLS_TPOFF32:
 222     case elfcpp::R_386_TLS_DESC:
 223       fprintf(stderr, _("%s: %s: unexpected reloc %u in object file\n"),
 224               program_name, object->name().c_str(), r_type);
 225       gold_exit(false);
 226       break;
 227
 228     case elfcpp::R_386_TLS_IE:
 229     case elfcpp::R_386_TLS_GOTIE:
 230     case elfcpp::R_386_TLS_LE:
 231     case elfcpp::R_386_TLS_GD:
 232     case elfcpp::R_386_TLS_LDM:
 233     case elfcpp::R_386_TLS_LDO_32:
 234     case elfcpp::R_386_TLS_IE_32:
 235     case elfcpp::R_386_TLS_LE_32:
 236     case elfcpp::R_386_TLS_GOTDESC:
 237     case elfcpp::R_386_TLS_DESC_CALL:
 238       r_type = Target_i386::optimize_tls_reloc(&options, true, r_type);
 239       switch (r_type)
 240         {
 241         case elfcpp::R_386_TLS_LE:
 242         case elfcpp::R_386_TLS_LE_32:
 243           // FIXME: If generating a shared object, we need to copy
 244           // this relocation into the object.
 245           break;
 246
 247         case elfcpp::R_386_TLS_IE:
 248         case elfcpp::R_386_TLS_GOTIE:
 249         case elfcpp::R_386_TLS_GD:
 250         case elfcpp::R_386_TLS_LDM:
 251         case elfcpp::R_386_TLS_LDO_32:
 252         case elfcpp::R_386_TLS_IE_32:
 253         case elfcpp::R_386_TLS_GOTDESC:
 254         case elfcpp::R_386_TLS_DESC_CALL:
 255           fprintf(stderr,
 256                   _("%s: %s: unsupported reloc %u against local symbol\n"),
 257                   program_name, object->name().c_str(), r_type);
 258           break;
 259         }
 260       break;
 261
 262     case elfcpp::R_386_GOT32:
 263     case elfcpp::R_386_PLT32:
 264     case elfcpp::R_386_GOTOFF:
 265     case elfcpp::R_386_GOTPC:
 266     case elfcpp::R_386_32PLT:
 267     case elfcpp::R_386_TLS_GD_32:
 268     case elfcpp::R_386_TLS_GD_PUSH:
 269     case elfcpp::R_386_TLS_GD_CALL:
 270     case elfcpp::R_386_TLS_GD_POP:
 271     case elfcpp::R_386_TLS_LDM_32:
 272     case elfcpp::R_386_TLS_LDM_PUSH:
 273     case elfcpp::R_386_TLS_LDM_CALL:
 274     case elfcpp::R_386_TLS_LDM_POP:
 275     case elfcpp::R_386_USED_BY_INTEL_200:
 276     default:
 277       fprintf(stderr, _("%s: %s: unsupported reloc %u against local symbol\n"),
 278               program_name, object->name().c_str(), r_type);
 279       break;
 280     }
 281 }
 282
 283 // Scan a relocation for a global symbol.
 284
 285 inline void
 286 Target_i386::Scan::global(const General_options& options,
 287                           Sized_object<32, false>* object,
 288                           const elfcpp::Rel<32, false>&, unsigned int r_type,
 289                           Symbol* gsym)
 290 {
 291   switch (r_type)
 292     {
 293     case elfcpp::R_386_NONE:
 294     case elfcpp::R_386_GNU_VTINHERIT:
 295     case elfcpp::R_386_GNU_VTENTRY:
 296       break;
 297
 298     case elfcpp::R_386_32:
 299     case elfcpp::R_386_PC32:
 300     case elfcpp::R_386_16:
 301     case elfcpp::R_386_PC16:
 302     case elfcpp::R_386_8:
 303     case elfcpp::R_386_PC8:
 304       // FIXME: If we are generating a shared object we may need to
 305       // copy this relocation into the object.  If this symbol is
 306       // defined in a shared object, we may need to copy this
 307       // relocation in order to avoid a COPY relocation.
 308       break;
 309
 310     case elfcpp::R_386_COPY:
 311     case elfcpp::R_386_GLOB_DAT:
 312     case elfcpp::R_386_JUMP_SLOT:
 313     case elfcpp::R_386_RELATIVE:
 314     case elfcpp::R_386_TLS_TPOFF:
 315     case elfcpp::R_386_TLS_DTPMOD32:
 316     case elfcpp::R_386_TLS_DTPOFF32:
 317     case elfcpp::R_386_TLS_TPOFF32:
 318     case elfcpp::R_386_TLS_DESC:
 319       fprintf(stderr, _("%s: %s: unexpected reloc %u in object file\n"),
 320               program_name, object->name().c_str(), r_type);
 321       gold_exit(false);
 322       break;
 323
 324     case elfcpp::R_386_TLS_IE:
 325     case elfcpp::R_386_TLS_GOTIE:
 326     case elfcpp::R_386_TLS_LE:
 327     case elfcpp::R_386_TLS_GD:
 328     case elfcpp::R_386_TLS_LDM:
 329     case elfcpp::R_386_TLS_LDO_32:
 330     case elfcpp::R_386_TLS_IE_32:
 331     case elfcpp::R_386_TLS_LE_32:
 332     case elfcpp::R_386_TLS_GOTDESC:
 333     case elfcpp::R_386_TLS_DESC_CALL:
 334       r_type = Target_i386::optimize_tls_reloc(&options,
 335                                                !gsym->in_dynsym(),
 336                                                r_type);
 337       switch (r_type)
 338         {
 339         case elfcpp::R_386_TLS_LE:
 340         case elfcpp::R_386_TLS_LE_32:
 341           // FIXME: If generating a shared object, we need to copy
 342           // this relocation into the object.
 343           break;
 344
 345         case elfcpp::R_386_TLS_IE:
 346         case elfcpp::R_386_TLS_GOTIE:
 347         case elfcpp::R_386_TLS_GD:
 348         case elfcpp::R_386_TLS_LDM:
 349         case elfcpp::R_386_TLS_LDO_32:
 350         case elfcpp::R_386_TLS_IE_32:
 351         case elfcpp::R_386_TLS_GOTDESC:
 352         case elfcpp::R_386_TLS_DESC_CALL:
 353           fprintf(stderr,
 354                   _("%s: %s: unsupported reloc %u against global symbol %s\n"),
 355                   program_name, object->name().c_str(), r_type, gsym->name());
 356           break;
 357         }
 358       break;
 359
 360     case elfcpp::R_386_GOT32:
 361     case elfcpp::R_386_PLT32:
 362     case elfcpp::R_386_GOTOFF:
 363     case elfcpp::R_386_GOTPC:
 364     case elfcpp::R_386_32PLT:
 365     case elfcpp::R_386_TLS_GD_32:
 366     case elfcpp::R_386_TLS_GD_PUSH:
 367     case elfcpp::R_386_TLS_GD_CALL:
 368     case elfcpp::R_386_TLS_GD_POP:
 369     case elfcpp::R_386_TLS_LDM_32:
 370     case elfcpp::R_386_TLS_LDM_PUSH:
 371     case elfcpp::R_386_TLS_LDM_CALL:
 372     case elfcpp::R_386_TLS_LDM_POP:
 373     case elfcpp::R_386_USED_BY_INTEL_200:
 374     default:
 375       fprintf(stderr,
 376               _("%s: %s: unsupported reloc %u against global symbol %s\n"),
 377               program_name, object->name().c_str(), r_type, gsym->name());
 378       break;
 379     }
 380 }
 381
 382 // Scan relocations for a section.
 383
 384 void
 385 Target_i386::scan_relocs(const General_options& options,
 386                          Symbol_table* symtab,
 387                          Sized_object<32, false>* object,
 388                          unsigned int sh_type,
 389                          const unsigned char* prelocs,
 390                          size_t reloc_count,
 391                          size_t local_symbol_count,
 392                          const unsigned char* plocal_symbols,
 393                          Symbol** global_symbols)
 394 {
 395   if (sh_type == elfcpp::SHT_RELA)
 396     {
 397       fprintf(stderr, _("%s: %s: unsupported RELA reloc section\n"),
 398               program_name, object->name().c_str());
 399       gold_exit(false);
 400     }
 401
 402   gold::scan_relocs<32, false, elfcpp::SHT_REL, Target_i386::Scan>(
 403     options,
 404     symtab,
 405     object,
 406     prelocs,
 407     reloc_count,
 408     local_symbol_count,
 409     plocal_symbols,
 410     global_symbols);
 411 }
 412
 413 // Perform a relocation.
 414
 415 inline void
 416 Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
 417                                 size_t relnum,
 418                                 const elfcpp::Rel<32, false>& rel,
 419                                 unsigned int r_type,
 420                                 Sized_symbol<32>* gsym,
 421                                 elfcpp::Elf_types<32>::Elf_Addr value,
 422                                 unsigned char* view,
 423                                 elfcpp::Elf_types<32>::Elf_Addr address,
 424                                 off_t view_size)
 425 {
 426   switch (r_type)
 427     {
 428     case elfcpp::R_386_NONE:
 429     case elfcpp::R_386_GNU_VTINHERIT:
 430     case elfcpp::R_386_GNU_VTENTRY:
 431       break;
 432
 433     case elfcpp::R_386_32:
 434       Relocate_functions<32, false>::rel32(view, value);
 435       break;
 436
 437     case elfcpp::R_386_PC32:
 438       Relocate_functions<32, false>::pcrel32(view, value, address);
 439       break;
 440
 441     case elfcpp::R_386_16:
 442       Relocate_functions<32, false>::rel16(view, value);
 443       break;
 444
 445     case elfcpp::R_386_PC16:
 446       Relocate_functions<32, false>::pcrel16(view, value, address);
 447       break;
 448
 449     case elfcpp::R_386_8:
 450       Relocate_functions<32, false>::rel8(view, value);
 451       break;
 452
 453     case elfcpp::R_386_PC8:
 454       Relocate_functions<32, false>::pcrel8(view, value, address);
 455       break;
 456
 457     case elfcpp::R_386_COPY:
 458     case elfcpp::R_386_GLOB_DAT:
 459     case elfcpp::R_386_JUMP_SLOT:
 460     case elfcpp::R_386_RELATIVE:
 461     case elfcpp::R_386_TLS_TPOFF:
 462     case elfcpp::R_386_TLS_DTPMOD32:
 463     case elfcpp::R_386_TLS_DTPOFF32:
 464     case elfcpp::R_386_TLS_TPOFF32:
 465     case elfcpp::R_386_TLS_DESC:
 466       fprintf(stderr, _("%s: %s: unexpected reloc %u in object file\n"),
 467               program_name,
 468               relinfo->location(relnum, rel.get_r_offset()).c_str(),
 469               r_type);
 470       gold_exit(false);
 471       break;
 472
 473     case elfcpp::R_386_TLS_IE:
 474     case elfcpp::R_386_TLS_GOTIE:
 475     case elfcpp::R_386_TLS_LE:
 476     case elfcpp::R_386_TLS_GD:
 477     case elfcpp::R_386_TLS_LDM:
 478     case elfcpp::R_386_TLS_LDO_32:
 479     case elfcpp::R_386_TLS_IE_32:
 480     case elfcpp::R_386_TLS_LE_32:
 481     case elfcpp::R_386_TLS_GOTDESC:
 482     case elfcpp::R_386_TLS_DESC_CALL:
 483       Target_i386::Relocate::relocate_tls(relinfo, relnum, rel, r_type,
 484                                           gsym, value, view, address,
 485                                           view_size);
 486       break;
 487
 488     case elfcpp::R_386_GOT32:
 489     case elfcpp::R_386_PLT32:
 490     case elfcpp::R_386_GOTOFF:
 491     case elfcpp::R_386_GOTPC:
 492     case elfcpp::R_386_32PLT:
 493     case elfcpp::R_386_TLS_GD_32:
 494     case elfcpp::R_386_TLS_GD_PUSH:
 495     case elfcpp::R_386_TLS_GD_CALL:
 496     case elfcpp::R_386_TLS_GD_POP:
 497     case elfcpp::R_386_TLS_LDM_32:
 498     case elfcpp::R_386_TLS_LDM_PUSH:
 499     case elfcpp::R_386_TLS_LDM_CALL:
 500     case elfcpp::R_386_TLS_LDM_POP:
 501     case elfcpp::R_386_USED_BY_INTEL_200:
 502     default:
 503       fprintf(stderr, _("%s: %s: unsupported reloc %u\n"),
 504               program_name,
 505               relinfo->location(relnum, rel.get_r_offset()).c_str(),
 506               r_type);
 507       // gold_exit(false);
 508       break;
 509     }
 510 }
 511
 512 // Perform a TLS relocation.
 513
 514 inline void
 515 Target_i386::Relocate::relocate_tls(const Relocate_info<32, false>* relinfo,
 516                                     size_t relnum,
 517                                     const elfcpp::Rel<32, false>& rel,
 518                                     unsigned int r_type,
 519                                     Sized_symbol<32>* gsym,
 520                                     elfcpp::Elf_types<32>::Elf_Addr value,
 521                                     unsigned char* view,
 522                                     elfcpp::Elf_types<32>::Elf_Addr,
 523                                     off_t view_size)
 524 {
 525   Output_segment* tls_segment = relinfo->layout->tls_segment();
 526   if (tls_segment == NULL)
 527     {
 528       fprintf(stderr, _("%s: %s: TLS reloc but no TLS segment\n"),
 529               program_name,
 530               relinfo->location(relnum, rel.get_r_offset()).c_str());
 531       gold_exit(false);
 532     }
 533
 534   const bool is_local = gsym == NULL || !gsym->in_dynsym();
 535   const unsigned int opt_r_type =
 536     Target_i386::optimize_tls_reloc(relinfo->options, is_local, r_type);
 537   switch (r_type)
 538     {
 539     case elfcpp::R_386_TLS_LE_32:
 540       value = tls_segment->vaddr() + tls_segment->memsz() - value;
 541       Relocate_functions<32, false>::rel32(view, value);
 542       break;
 543
 544     case elfcpp::R_386_TLS_LE:
 545       value = value - (tls_segment->vaddr() + tls_segment->memsz());
 546       Relocate_functions<32, false>::rel32(view, value);
 547       break;
 548
 549     case elfcpp::R_386_TLS_IE:
 550     case elfcpp::R_386_TLS_GOTIE:
 551     case elfcpp::R_386_TLS_IE_32:
 552       if (opt_r_type == elfcpp::R_386_TLS_LE_32)
 553         {
 554           Target_i386::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
 555                                               rel, r_type, value, view,
 556                                               view_size);
 557           break;
 558         }
 559       fprintf(stderr, _("%s: %s: unsupported reloc type %u\n"),
 560               program_name,
 561               relinfo->location(relnum, rel.get_r_offset()).c_str(),
 562               r_type);
 563       // gold_exit(false);
 564       break;
 565
 566     case elfcpp::R_386_TLS_GD:
 567     case elfcpp::R_386_TLS_LDM:
 568     case elfcpp::R_386_TLS_LDO_32:
 569     case elfcpp::R_386_TLS_GOTDESC:
 570     case elfcpp::R_386_TLS_DESC_CALL:
 571       fprintf(stderr, _("%s: %s: unsupported reloc %u\n"),
 572               program_name,
 573               relinfo->location(relnum, rel.get_r_offset()).c_str(),
 574               r_type);
 575       // gold_exit(false);
 576       break;
 577     }
 578 }
 579
 580 // Do a relocation in which we convert a TLS Initial-Exec to a
 581 // Local-Exec.
 582
 583 inline void
 584 Target_i386::Relocate::tls_ie_to_le(const Relocate_info<32, false>* relinfo,
 585                                     size_t relnum,
 586                                     Output_segment* tls_segment,
 587                                     const elfcpp::Rel<32, false>& rel,
 588                                     unsigned int r_type,
 589                                     elfcpp::Elf_types<32>::Elf_Addr value,
 590                                     unsigned char* view,
 591                                     off_t view_size)
 592 {
 593   // We have to actually change the instructions, which means that we
 594   // need to examine the opcodes to figure out which instruction we
 595   // are looking at.
 596   if (r_type == elfcpp::R_386_TLS_IE)
 597     {
 598       // movl %gs:XX,%eax  ==>  movl $YY,%eax
 599       // movl %gs:XX,%reg  ==>  movl $YY,%reg
 600       // addl %gs:XX,%reg  ==>  addl $YY,%reg
 601       Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, -1);
 602       Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, 4);
 603
 604       unsigned char op1 = view[-1];
 605       if (op1 == 0xa1)
 606         {
 607           // movl XX,%eax  ==>  movl $YY,%eax
 608           view[-1] = 0xb8;
 609         }
 610       else
 611         {
 612           Target_i386::Relocate::check_range(relinfo, relnum, rel,
 613                                              view_size, -2);
 614
 615           unsigned char op2 = view[-2];
 616           if (op2 == 0x8b)
 617             {
 618               // movl XX,%reg  ==>  movl $YY,%reg
 619               Target_i386::Relocate::check_tls(relinfo, relnum, rel,
 620                                                (op1 & 0xc7) == 0x05);
 621               view[-2] = 0xc7;
 622               view[-1] = 0xc0 | ((op1 >> 3) & 7);
 623             }
 624           else if (op2 == 0x03)
 625             {
 626               // addl XX,%reg  ==>  addl $YY,%reg
 627               Target_i386::Relocate::check_tls(relinfo, relnum, rel,
 628                                                (op1 & 0xc7) == 0x05);
 629               view[-2] = 0x81;
 630               view[-1] = 0xc0 | ((op1 >> 3) & 7);
 631             }
 632           else
 633             Target_i386::Relocate::check_tls(relinfo, relnum, rel, 0);
 634         }
 635     }
 636   else
 637     {
 638       // subl %gs:XX(%reg1),%reg2  ==>  subl $YY,%reg2
 639       // movl %gs:XX(%reg1),%reg2  ==>  movl $YY,%reg2
 640       // addl %gs:XX(%reg1),%reg2  ==>  addl $YY,$reg2
 641       Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, -2);
 642       Target_i386::Relocate::check_range(relinfo, relnum, rel, view_size, 4);
 643
 644       unsigned char op1 = view[-1];
 645       unsigned char op2 = view[-2];
 646       Target_i386::Relocate::check_tls(relinfo, relnum, rel,
 647                                        (op1 & 0xc0) == 0x80 && (op1 & 7) != 4);
 648       if (op2 == 0x8b)
 649         {
 650           // movl %gs:XX(%reg1),%reg2  ==>  movl $YY,%reg2
 651           view[-2] = 0xc7;
 652           view[-1] = 0xc0 | ((op1 >> 3) & 7);
 653         }
 654       else if (op2 == 0x2b)
 655         {
 656           // subl %gs:XX(%reg1),%reg2  ==>  subl $YY,%reg2
 657           view[-2] = 0x81;
 658           view[-1] = 0xe8 | ((op1 >> 3) & 7);
 659         }
 660       else if (op2 == 0x03)
 661         {
 662           // addl %gs:XX(%reg1),%reg2  ==>  addl $YY,$reg2
 663           view[-2] = 0x81;
 664           view[-1] = 0xc0 | ((op1 >> 3) & 7);
 665         }
 666       else
 667         Target_i386::Relocate::check_tls(relinfo, relnum, rel, 0);
 668     }
 669
 670   if (r_type == elfcpp::R_386_TLS_IE_32)
 671     value = tls_segment->vaddr() + tls_segment->memsz() - value;
 672   else // elfcpp::R_386_TLS_IE, elfcpp::R_386_TLS_GOTIE
 673     value = value - (tls_segment->vaddr() + tls_segment->memsz());
 674
 675   Relocate_functions<32, false>::rel32(view, value);
 676 }
 677
 678 // Check the range for a TLS relocation.
 679
 680 inline void
 681 Target_i386::Relocate::check_range(const Relocate_info<32, false>* relinfo,
 682                                    size_t relnum,
 683                                    const elfcpp::Rel<32, false>& rel,
 684                                    off_t view_size, off_t off)
 685 {
 686   off_t offset = rel.get_r_offset() + off;
 687   if (offset < 0 || offset > view_size)
 688     {
 689       fprintf(stderr, _("%s: %s: TLS relocation out of range\n"),
 690               program_name,
 691               relinfo->location(relnum, rel.get_r_offset()).c_str());
 692       gold_exit(false);
 693     }
 694 }
 695
 696 // Check the validity of a TLS relocation.  This is like assert.
 697
 698 inline void
 699 Target_i386::Relocate::check_tls(const Relocate_info<32, false>* relinfo,
 700                                  size_t relnum,
 701                                  const elfcpp::Rel<32, false>& rel,
 702                                  bool valid)
 703 {
 704   if (!valid)
 705     {
 706       fprintf(stderr,
 707               _("%s: %s: TLS relocation against invalid instruction\n"),
 708               program_name,
 709               relinfo->location(relnum, rel.get_r_offset()).c_str());
 710       gold_exit(false);
 711     }
 712 }
 713
 714 // Relocate section data.
 715
 716 void
 717 Target_i386::relocate_section(const Relocate_info<32, false>* relinfo,
 718                               unsigned int sh_type,
 719                               const unsigned char* prelocs,
 720                               size_t reloc_count,
 721                               unsigned char* view,
 722                               elfcpp::Elf_types<32>::Elf_Addr address,
 723                               off_t view_size)
 724 {
 725   assert(sh_type == elfcpp::SHT_REL);
 726
 727   gold::relocate_section<32, false, elfcpp::SHT_REL, Target_i386::Relocate>(
 728     relinfo,
 729     prelocs,
 730     reloc_count,
 731     view,
 732     address,
 733     view_size);
 734 }
 735
 736 // The i386 target.
 737
 738 Target_i386 target_i386;
 739
 740 // The selector for i386 object files.
 741
 742 class Target_selector_i386 : public Target_selector
 743 {
 744 public:
 745   Target_selector_i386()
 746     : Target_selector(elfcpp::EM_386, 32, false)
 747   { }
 748
 749   Target*
 750   recognize(int machine, int osabi, int abiversion) const;
 751 };
 752
 753 // Recognize an i386 object file when we already know that the machine
 754 // number is EM_386.
 755
 756 Target*
 757 Target_selector_i386::recognize(int, int, int) const
 758 {
 759   return &target_i386;
 760 }
 761
 762 Target_selector_i386 target_selector_i386;
 763
 764 } // End anonymous namespace.