bfd/elfxx-x86.h

   1 /* x86 specific support for ELF
   2    Copyright (C) 2017-2021 Free Software Foundation, Inc.
   3
   4    This file is part of BFD, the Binary File Descriptor library.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  19    MA 02110-1301, USA.  */
  20
  21 /* Don't generate unused section symbols.  */
  22 #define TARGET_KEEP_UNUSED_SECTION_SYMBOLS false
  23
  24 #include "sysdep.h"
  25 #include "bfd.h"
  26 #include "bfdlink.h"
  27 #include "libbfd.h"
  28 #include "elf-bfd.h"
  29 #include "hashtab.h"
  30 #include "elf-linker-x86.h"
  31
  32 #define PLT_CIE_LENGTH          20
  33 #define PLT_FDE_LENGTH          36
  34 #define PLT_FDE_START_OFFSET    4 + PLT_CIE_LENGTH + 8
  35 #define PLT_FDE_LEN_OFFSET      4 + PLT_CIE_LENGTH + 12
  36
  37 #define ABI_64_P(abfd) \
  38   (get_elf_backend_data (abfd)->s->elfclass == ELFCLASS64)
  39
  40 /* If ELIMINATE_COPY_RELOCS is non-zero, the linker will try to avoid
  41    copying dynamic variables from a shared lib into an app's dynbss
  42    section, and instead use a dynamic relocation to point into the
  43    shared lib.  */
  44 #define ELIMINATE_COPY_RELOCS 1
  45
  46 #define elf_x86_hash_table(p, id) \
  47   (is_elf_hash_table ((p)->hash) \
  48    && elf_hash_table_id ((struct elf_link_hash_table *) ((p)->hash)) == (id) \
  49     ? ((struct elf_x86_link_hash_table *) ((p)->hash)) : NULL)
  50
  51 /* Will references to this symbol always be local in this object?  */
  52 #define SYMBOL_REFERENCES_LOCAL_P(INFO, H) \
  53   _bfd_x86_elf_link_symbol_references_local ((INFO), (H))
  54
  55 /* TRUE if an undefined weak symbol should be resolved to 0.  Local
  56    undefined weak symbol is always resolved to 0.  Reference to an
  57    undefined weak symbol is resolved to 0 in executable if undefined
  58    weak symbol should be resolved to 0 (zero_undefweak > 0).  */
  59 #define UNDEFINED_WEAK_RESOLVED_TO_ZERO(INFO, EH) \
  60   ((EH)->elf.root.type == bfd_link_hash_undefweak                \
  61    && (SYMBOL_REFERENCES_LOCAL_P ((INFO), &(EH)->elf)            \
  62        || (bfd_link_executable (INFO)                            \
  63            && (EH)->zero_undefweak > 0)))
  64
  65 /* Should copy relocation be generated for a symbol.  Don't generate
  66    copy relocation against a protected symbol defined in a shared
  67    object with GNU_PROPERTY_NO_COPY_ON_PROTECTED.  */
  68 #define SYMBOL_NO_COPYRELOC(INFO, EH) \
  69   ((EH)->def_protected \
  70    && ((EH)->elf.root.type == bfd_link_hash_defined \
  71        || (EH)->elf.root.type == bfd_link_hash_defweak) \
  72    && elf_has_no_copy_on_protected ((EH)->elf.root.u.def.section->owner) \
  73    && ((EH)->elf.root.u.def.section->owner->flags & DYNAMIC) != 0 \
  74    && ((EH)->elf.root.u.def.section->flags & SEC_CODE) == 0)
  75
  76 /* TRUE if dynamic relocation is needed.  If we are creating a shared
  77    library, and this is a reloc against a global symbol, or a non PC
  78    relative reloc against a local symbol, then we need to copy the reloc
  79    into the shared library.  However, if we are linking with -Bsymbolic,
  80    we do not need to copy a reloc against a global symbol which is
  81    defined in an object we are including in the link (i.e., DEF_REGULAR
  82    is set).
  83
  84    If PCREL_PLT is true, don't generate dynamic relocation in PIE for
  85    PC-relative relocation against a dynamic function definition in data
  86    section when PLT address can be used.
  87
  88    If on the other hand, we are creating an executable, we may need to
  89    keep relocations for symbols satisfied by a dynamic library if we
  90    manage to avoid copy relocs for the symbol.
  91
  92    We also need to generate dynamic pointer relocation against
  93    STT_GNU_IFUNC symbol in the non-code section.  */
  94 #define NEED_DYNAMIC_RELOCATION_P(INFO, PCREL_PLT, H, SEC, R_TYPE, \
  95                                   POINTER_TYPE) \
  96   ((bfd_link_pic (INFO) \
  97     && (! X86_PCREL_TYPE_P (R_TYPE) \
  98         || ((H) != NULL \
  99             && (! (bfd_link_pie (INFO) \
 100                    || SYMBOLIC_BIND ((INFO), (H))) \
 101                 || (H)->root.type == bfd_link_hash_defweak \
 102                 || (!(bfd_link_pie (INFO) \
 103                       && (PCREL_PLT) \
 104                       && (H)->plt.refcount > 0 \
 105                       && ((SEC)->flags & SEC_CODE) == 0 \
 106                       && (H)->type == STT_FUNC \
 107                       && (H)->def_dynamic) \
 108                     && !(H)->def_regular))))) \
 109    || ((H) != NULL \
 110        && (H)->type == STT_GNU_IFUNC \
 111        && (R_TYPE) == POINTER_TYPE \
 112        && ((SEC)->flags & SEC_CODE) == 0) \
 113    || (ELIMINATE_COPY_RELOCS \
 114        && !bfd_link_pic (INFO) \
 115        && (H) != NULL \
 116        && ((H)->root.type == bfd_link_hash_defweak \
 117            || !(H)->def_regular)))
 118
 119 /* TRUE if dynamic relocation should be generated.  Don't copy a
 120    pc-relative relocation into the output file if the symbol needs
 121    copy reloc or the symbol is undefined when building executable.
 122    Copy dynamic function pointer relocations.  Don't generate dynamic
 123    relocations against resolved undefined weak symbols in PIE, except
 124    when PC32_RELOC is TRUE.  Undefined weak symbol is bound locally
 125    when PIC is false.  Don't generate dynamic relocations against
 126    non-preemptible absolute symbol.  */
 127 #define GENERATE_DYNAMIC_RELOCATION_P(INFO, EH, R_TYPE, SEC, \
 128                                       NEED_COPY_RELOC_IN_PIE, \
 129                                       RESOLVED_TO_ZERO, PC32_RELOC) \
 130   ((bfd_link_pic (INFO) \
 131     && !(bfd_is_abs_section (SEC) \
 132          && ((EH) == NULL \
 133              || SYMBOL_REFERENCES_LOCAL (INFO, &(EH)->elf))) \
 134     && !(NEED_COPY_RELOC_IN_PIE) \
 135     && ((EH) == NULL \
 136         || ((ELF_ST_VISIBILITY ((EH)->elf.other) == STV_DEFAULT \
 137              && (!(RESOLVED_TO_ZERO) || PC32_RELOC)) \
 138             || (EH)->elf.root.type != bfd_link_hash_undefweak)) \
 139     && ((!X86_PCREL_TYPE_P (R_TYPE) && !X86_SIZE_TYPE_P (R_TYPE)) \
 140         || ! SYMBOL_CALLS_LOCAL ((INFO), \
 141                                  (struct elf_link_hash_entry *) (EH)))) \
 142    || (ELIMINATE_COPY_RELOCS \
 143        && !bfd_link_pic (INFO) \
 144        && (EH) != NULL \
 145        && (EH)->elf.dynindx != -1 \
 146        && (!(EH)->elf.non_got_ref \
 147            || ((EH)->elf.root.type == bfd_link_hash_undefweak \
 148                && !(RESOLVED_TO_ZERO))) \
 149                && (((EH)->elf.def_dynamic && !(EH)->elf.def_regular) \
 150                    || (EH)->elf.root.type == bfd_link_hash_undefined)))
 151
 152 /* TRUE if this input relocation should be copied to output.  H->dynindx
 153    may be -1 if this symbol was marked to become local.  */
 154 #define COPY_INPUT_RELOC_P(INFO, H, R_TYPE) \
 155   ((H) != NULL \
 156    && (H)->dynindx != -1 \
 157    && (X86_PCREL_TYPE_P (R_TYPE) \
 158        || !(bfd_link_executable (INFO) || SYMBOLIC_BIND ((INFO), (H))) \
 159        || !(H)->def_regular))
 160
 161 /* TRUE if this is actually a static link, or it is a -Bsymbolic link
 162    and the symbol is defined locally, or the symbol was forced to be
 163    local because of a version file.  */
 164 #define RESOLVED_LOCALLY_P(INFO, H, HTAB) \
 165   (!WILL_CALL_FINISH_DYNAMIC_SYMBOL ((HTAB)->elf.dynamic_sections_created, \
 166                                      bfd_link_pic (INFO), (H)) \
 167    || (bfd_link_pic (INFO) \
 168        && SYMBOL_REFERENCES_LOCAL_P ((INFO), (H))) \
 169        || (ELF_ST_VISIBILITY ((H)->other) \
 170            && (H)->root.type == bfd_link_hash_undefweak))
 171
 172 /* TRUE if this symbol isn't defined by a shared object.  */
 173 #define SYMBOL_DEFINED_NON_SHARED_P(H) \
 174   ((H)->def_regular \
 175    || (H)->root.linker_def \
 176    || (H)->root.ldscript_def \
 177    || ((struct elf_x86_link_hash_entry *) (H))->linker_def \
 178    || ELF_COMMON_DEF_P (H))
 179
 180 /* Return TRUE if the symbol described by a linker hash entry H is
 181    going to be absolute.  Similar to bfd_is_abs_symbol, but excluding
 182    all linker-script defined symbols.  */
 183 #define ABS_SYMBOL_P(H) \
 184   (bfd_is_abs_symbol (&(H)->root) && !(H)->root.ldscript_def)
 185
 186 /* TRUE if relative relocation should be generated.  GOT reference to
 187    global symbol in PIC will lead to dynamic symbol.  It becomes a
 188    problem when "time" or "times" is defined as a variable in an
 189    executable, clashing with functions of the same name in libc.  If a
 190    symbol isn't undefined weak symbol, don't make it dynamic in PIC and
 191    generate relative relocation.   Don't generate relative relocation
 192    against non-preemptible absolute symbol.  */
 193 #define GENERATE_RELATIVE_RELOC_P(INFO, H) \
 194   ((H)->dynindx == -1 \
 195    && !(H)->forced_local \
 196    && (H)->root.type != bfd_link_hash_undefweak \
 197    && bfd_link_pic (INFO) \
 198    && !ABS_SYMBOL_P (H))
 199
 200 /* TRUE if this is a pointer reference to a local IFUNC.  */
 201 #define POINTER_LOCAL_IFUNC_P(INFO, H) \
 202   ((H)->dynindx == -1 \
 203    || (H)->forced_local \
 204    || bfd_link_executable (INFO))
 205
 206 /* TRUE if this is a PLT reference to a local IFUNC.  */
 207 #define PLT_LOCAL_IFUNC_P(INFO, H) \
 208   ((H)->dynindx == -1 \
 209    || ((bfd_link_executable (INFO) \
 210         || ELF_ST_VISIBILITY ((H)->other) != STV_DEFAULT) \
 211         && (H)->def_regular \
 212         && (H)->type == STT_GNU_IFUNC))
 213
 214 /* TRUE if TLS IE->LE transition is OK.  */
 215 #define TLS_TRANSITION_IE_TO_LE_P(INFO, H, TLS_TYPE) \
 216   (bfd_link_executable (INFO) \
 217    && (H) != NULL \
 218    && (H)->dynindx == -1 \
 219    && (TLS_TYPE & GOT_TLS_IE))
 220
 221 /* Verify that the symbol has an entry in the procedure linkage table.  */
 222 #define VERIFY_PLT_ENTRY(INFO, H, PLT, GOTPLT, RELPLT, LOCAL_UNDEFWEAK) \
 223   do \
 224     { \
 225       if (((H)->dynindx == -1 \
 226            && !LOCAL_UNDEFWEAK \
 227            && !(((H)->forced_local || bfd_link_executable (INFO)) \
 228                 && (H)->def_regular \
 229                 && (H)->type == STT_GNU_IFUNC)) \
 230           || (PLT) == NULL \
 231           || (GOTPLT) == NULL \
 232           || (RELPLT) == NULL) \
 233         abort (); \
 234     } \
 235   while (0);
 236
 237 /* Verify that the symbol supports copy relocation.  */
 238 #define VERIFY_COPY_RELOC(H, HTAB) \
 239   do \
 240     { \
 241       if ((H)->dynindx == -1 \
 242           || ((H)->root.type != bfd_link_hash_defined \
 243               && (H)->root.type != bfd_link_hash_defweak) \
 244           || (HTAB)->elf.srelbss == NULL \
 245           || (HTAB)->elf.sreldynrelro == NULL) \
 246         abort (); \
 247     } \
 248   while (0);
 249
 250 /* x86 ELF linker hash entry.  */
 251
 252 struct elf_x86_link_hash_entry
 253 {
 254   struct elf_link_hash_entry elf;
 255
 256   unsigned char tls_type;
 257
 258   /* Bit 0: Symbol has no GOT nor PLT relocations.
 259      Bit 1: Symbol has non-GOT/non-PLT relocations in text sections.
 260      zero_undefweak is initialized to 1 and undefined weak symbol
 261      should be resolved to 0 if zero_undefweak > 0.  */
 262   unsigned int zero_undefweak : 2;
 263
 264   /* Don't call finish_dynamic_symbol on this symbol.  */
 265   unsigned int no_finish_dynamic_symbol : 1;
 266
 267   /* TRUE if symbol is __tls_get_addr.  */
 268   unsigned int tls_get_addr : 1;
 269
 270   /* TRUE if symbol is defined as a protected symbol.  */
 271   unsigned int def_protected : 1;
 272
 273   /* 0: Symbol references are unknown.
 274      1: Symbol references aren't local.
 275      2: Symbol references are local.
 276    */
 277   unsigned int local_ref : 2;
 278
 279   /* TRUE if symbol is defined by linker.  */
 280   unsigned int linker_def : 1;
 281
 282   /* TRUE if symbol is referenced by a non-GOT/non-PLT relocation in a
 283      relocatable object file without indirect external access marker.  */
 284   unsigned int non_got_ref_without_indirect_extern_access : 1;
 285
 286   /* TRUE if symbol is referenced by R_386_GOTOFF relocation.  This is
 287      only used by i386.  */
 288   unsigned int gotoff_ref : 1;
 289
 290   /* TRUE if a weak symbol with a real definition needs a copy reloc.
 291      When there is a weak symbol with a real definition, the processor
 292      independent code will have arranged for us to see the real
 293      definition first.  We need to copy the needs_copy bit from the
 294      real definition and check it when allowing copy reloc in PIE.  This
 295      is only used by x86-64.  */
 296   unsigned int needs_copy : 1;
 297
 298   /* Information about the GOT PLT entry. Filled when there are both
 299      GOT and PLT relocations against the same function.  */
 300   union gotplt_union plt_got;
 301
 302   /* Information about the second PLT entry.   */
 303   union gotplt_union plt_second;
 304
 305   /* Offset of the GOTPLT entry reserved for the TLS descriptor,
 306      starting at the end of the jump table.  */
 307   bfd_vma tlsdesc_got;
 308 };
 309
 310 struct elf_x86_lazy_plt_layout
 311 {
 312   /* The first entry in a lazy procedure linkage table looks like this.  */
 313   const bfd_byte *plt0_entry;
 314   unsigned int plt0_entry_size;          /* Size of PLT0 entry.  */
 315
 316   /* Later entries in a lazy procedure linkage table look like this.  */
 317   const bfd_byte *plt_entry;
 318   unsigned int plt_entry_size;          /* Size of each PLT entry.  */
 319
 320   /* The TLSDESC entry in a lazy procedure linkage table looks like
 321      this.  This is for x86-64 only.  */
 322   const bfd_byte *plt_tlsdesc_entry;
 323   unsigned int plt_tlsdesc_entry_size;   /* Size of TLSDESC entry.  */
 324
 325   /* Offsets into the TLSDESC entry that are to be replaced with
 326      GOT+8 and GOT+TDG.  These are for x86-64 only.  */
 327   unsigned int plt_tlsdesc_got1_offset;
 328   unsigned int plt_tlsdesc_got2_offset;
 329
 330   /* Offset of the end of the PC-relative instructions containing
 331      plt_tlsdesc_got1_offset and plt_tlsdesc_got2_offset.  These
 332      are for x86-64 only.  */
 333   unsigned int plt_tlsdesc_got1_insn_end;
 334   unsigned int plt_tlsdesc_got2_insn_end;
 335
 336   /* Offsets into plt0_entry that are to be replaced with GOT[1] and
 337      GOT[2].  */
 338   unsigned int plt0_got1_offset;
 339   unsigned int plt0_got2_offset;
 340
 341   /* Offset of the end of the PC-relative instruction containing
 342      plt0_got2_offset.  This is for x86-64 only.  */
 343   unsigned int plt0_got2_insn_end;
 344
 345   /* Offsets into plt_entry that are to be replaced with...  */
 346   unsigned int plt_got_offset;    /* ... address of this symbol in .got. */
 347   unsigned int plt_reloc_offset;  /* ... offset into relocation table. */
 348   unsigned int plt_plt_offset;    /* ... offset to start of .plt. */
 349
 350   /* Length of the PC-relative instruction containing plt_got_offset.
 351      This is used for x86-64 only.  */
 352   unsigned int plt_got_insn_size;
 353
 354   /* Offset of the end of the PC-relative jump to plt0_entry.  This is
 355      used for x86-64 only.  */
 356   unsigned int plt_plt_insn_end;
 357
 358   /* Offset into plt_entry where the initial value of the GOT entry
 359      points.  */
 360   unsigned int plt_lazy_offset;
 361
 362   /* The first entry in a PIC lazy procedure linkage table looks like
 363      this.  */
 364   const bfd_byte *pic_plt0_entry;
 365
 366   /* Subsequent entries in a PIC lazy procedure linkage table look
 367      like this.  */
 368   const bfd_byte *pic_plt_entry;
 369
 370   /* .eh_frame covering the lazy .plt section.  */
 371   const bfd_byte *eh_frame_plt;
 372   unsigned int eh_frame_plt_size;
 373 };
 374
 375 struct elf_x86_non_lazy_plt_layout
 376 {
 377   /* Entries in a non-lazy procedure linkage table look like this.  */
 378   const bfd_byte *plt_entry;
 379   /* Entries in a PIC non-lazy procedure linkage table look like this.
 380      This is only used for i386 where absolute PLT and PIC PLT are
 381      different.  */
 382   const bfd_byte *pic_plt_entry;
 383
 384   unsigned int plt_entry_size;          /* Size of each PLT entry.  */
 385
 386   /* Offsets into plt_entry that are to be replaced with...  */
 387   unsigned int plt_got_offset;    /* ... address of this symbol in .got. */
 388
 389   /* Length of the PC-relative instruction containing plt_got_offset.
 390      This is used for x86-64 only.  */
 391   unsigned int plt_got_insn_size;
 392
 393   /* .eh_frame covering the non-lazy .plt section.  */
 394   const bfd_byte *eh_frame_plt;
 395   unsigned int eh_frame_plt_size;
 396 };
 397
 398 struct elf_x86_plt_layout
 399 {
 400   /* The first entry in a lazy procedure linkage table looks like this.  */
 401   const bfd_byte *plt0_entry;
 402   /* Entries in a procedure linkage table look like this.  */
 403   const bfd_byte *plt_entry;
 404   unsigned int plt_entry_size;          /* Size of each PLT entry.  */
 405
 406   /* 1 has PLT0.  */
 407   unsigned int has_plt0;
 408
 409   /* Offsets into plt_entry that are to be replaced with...  */
 410   unsigned int plt_got_offset;    /* ... address of this symbol in .got. */
 411
 412   /* Length of the PC-relative instruction containing plt_got_offset.
 413      This is only used for x86-64.  */
 414   unsigned int plt_got_insn_size;
 415
 416   /* Alignment of the .iplt section.  */
 417   unsigned int iplt_alignment;
 418
 419   /* .eh_frame covering the .plt section.  */
 420   const bfd_byte *eh_frame_plt;
 421   unsigned int eh_frame_plt_size;
 422 };
 423
 424 /* Values in tls_type of x86 ELF linker hash entry.  */
 425 #define GOT_UNKNOWN     0
 426 #define GOT_NORMAL      1
 427 #define GOT_TLS_GD      2
 428 #define GOT_TLS_IE      4
 429 #define GOT_TLS_IE_POS  5
 430 #define GOT_TLS_IE_NEG  6
 431 #define GOT_TLS_IE_BOTH 7
 432 #define GOT_TLS_GDESC   8
 433 #define GOT_ABS         9
 434 #define GOT_TLS_GD_BOTH_P(type) \
 435   ((type) == (GOT_TLS_GD | GOT_TLS_GDESC))
 436 #define GOT_TLS_GD_P(type) \
 437   ((type) == GOT_TLS_GD || GOT_TLS_GD_BOTH_P (type))
 438 #define GOT_TLS_GDESC_P(type) \
 439   ((type) == GOT_TLS_GDESC || GOT_TLS_GD_BOTH_P (type))
 440 #define GOT_TLS_GD_ANY_P(type) \
 441   (GOT_TLS_GD_P (type) || GOT_TLS_GDESC_P (type))
 442
 443 #define elf_x86_hash_entry(ent) \
 444   ((struct elf_x86_link_hash_entry *)(ent))
 445
 446 /* x86 ELF linker hash table.  */
 447
 448 struct elf_x86_link_hash_table
 449 {
 450   struct elf_link_hash_table elf;
 451
 452   /* Short-cuts to get to dynamic linker sections.  */
 453   asection *interp;
 454   asection *plt_eh_frame;
 455   asection *plt_second;
 456   asection *plt_second_eh_frame;
 457   asection *plt_got;
 458   asection *plt_got_eh_frame;
 459
 460   /* Parameters describing PLT generation, lazy or non-lazy.  */
 461   struct elf_x86_plt_layout plt;
 462
 463   /* Parameters describing lazy PLT generation.  */
 464   const struct elf_x86_lazy_plt_layout *lazy_plt;
 465
 466   /* Parameters describing non-lazy PLT generation.  */
 467   const struct elf_x86_non_lazy_plt_layout *non_lazy_plt;
 468
 469   union
 470   {
 471     bfd_signed_vma refcount;
 472     bfd_vma offset;
 473   } tls_ld_or_ldm_got;
 474
 475   /* The amount of space used by the jump slots in the GOT.  */
 476   bfd_vma sgotplt_jump_table_size;
 477
 478   /* _TLS_MODULE_BASE_ symbol.  */
 479   struct bfd_link_hash_entry *tls_module_base;
 480
 481   /* Used by local STT_GNU_IFUNC symbols.  */
 482   htab_t loc_hash_table;
 483   void * loc_hash_memory;
 484
 485   /* The index of the next R_X86_64_JUMP_SLOT entry in .rela.plt.  */
 486   bfd_vma next_jump_slot_index;
 487   /* The index of the next R_X86_64_IRELATIVE entry in .rela.plt.  */
 488   bfd_vma next_irelative_index;
 489
 490   /* The (unloaded but important) .rel.plt.unloaded section on VxWorks.
 491      This is used for i386 only.  */
 492   asection *srelplt2;
 493
 494   /* The index of the next unused R_386_TLS_DESC slot in .rel.plt.  This
 495      is only used for i386.  */
 496   bfd_vma next_tls_desc_index;
 497
 498    /* Value used to fill the unused bytes of the first PLT entry.  This
 499       is only used for i386.  */
 500   bfd_byte plt0_pad_byte;
 501
 502   /* TRUE if GOT is referenced.  */
 503   unsigned int got_referenced : 1;
 504
 505   /* TRUE if PLT is PC-relative.  PLT in PDE and PC-relative PLT in PIE
 506      can be used as function address.
 507
 508      NB: i386 has non-PIC PLT and PIC PLT.  Only non-PIC PLT in PDE can
 509      be used as function address.  PIC PLT in PIE can't be used as
 510      function address.  */
 511   unsigned int pcrel_plt : 1;
 512
 513   bfd_vma (*r_info) (bfd_vma, bfd_vma);
 514   bfd_vma (*r_sym) (bfd_vma);
 515   bool (*is_reloc_section) (const char *);
 516   unsigned int sizeof_reloc;
 517   unsigned int got_entry_size;
 518   unsigned int pointer_r_type;
 519   int dynamic_interpreter_size;
 520   const char *dynamic_interpreter;
 521   const char *tls_get_addr;
 522
 523   /* Options passed from the linker.  */
 524   struct elf_linker_x86_params *params;
 525 };
 526
 527 struct elf_x86_init_table
 528 {
 529   /* The lazy PLT layout.  */
 530   const struct elf_x86_lazy_plt_layout *lazy_plt;
 531
 532   /* The non-lazy PLT layout.  */
 533   const struct elf_x86_non_lazy_plt_layout *non_lazy_plt;
 534
 535   /* The lazy PLT layout for IBT.  */
 536   const struct elf_x86_lazy_plt_layout *lazy_ibt_plt;
 537
 538   /* The non-lazy PLT layout for IBT.  */
 539   const struct elf_x86_non_lazy_plt_layout *non_lazy_ibt_plt;
 540
 541   bfd_byte plt0_pad_byte;
 542
 543   bfd_vma (*r_info) (bfd_vma, bfd_vma);
 544   bfd_vma (*r_sym) (bfd_vma);
 545 };
 546
 547 struct elf_x86_obj_tdata
 548 {
 549   struct elf_obj_tdata root;
 550
 551   /* tls_type for each local got entry.  */
 552   char *local_got_tls_type;
 553
 554   /* GOTPLT entries for TLS descriptors.  */
 555   bfd_vma *local_tlsdesc_gotent;
 556 };
 557
 558 enum elf_x86_plt_type
 559 {
 560   plt_non_lazy = 0,
 561   plt_lazy = 1 << 0,
 562   plt_pic = 1 << 1,
 563   plt_second = 1 << 2,
 564   plt_unknown = -1
 565 };
 566
 567 struct elf_x86_plt
 568 {
 569   const char *name;
 570   asection *sec;
 571   bfd_byte *contents;
 572   enum elf_x86_plt_type type;
 573   unsigned int plt_got_offset;
 574   unsigned int plt_entry_size;
 575   unsigned int plt_got_insn_size;       /* Only used for x86-64.  */
 576   long count;
 577 };
 578
 579 /* Set if a relocation is converted from a GOTPCREL relocation.  */
 580 #define R_X86_64_converted_reloc_bit (1 << 7)
 581
 582 #define elf_x86_tdata(abfd) \
 583   ((struct elf_x86_obj_tdata *) (abfd)->tdata.any)
 584
 585 #define elf_x86_local_got_tls_type(abfd) \
 586   (elf_x86_tdata (abfd)->local_got_tls_type)
 587
 588 #define elf_x86_local_tlsdesc_gotent(abfd) \
 589   (elf_x86_tdata (abfd)->local_tlsdesc_gotent)
 590
 591 #define elf_x86_compute_jump_table_size(htab) \
 592   ((htab)->elf.srelplt->reloc_count * (htab)->got_entry_size)
 593
 594 #define is_x86_elf(bfd, htab)                           \
 595   (bfd_get_flavour (bfd) == bfd_target_elf_flavour      \
 596    && elf_tdata (bfd) != NULL                           \
 597    && elf_object_id (bfd) == (htab)->elf.hash_table_id)
 598
 599 extern bool _bfd_x86_elf_mkobject
 600   (bfd *);
 601
 602 extern void _bfd_x86_elf_set_tls_module_base
 603   (struct bfd_link_info *);
 604
 605 extern bfd_vma _bfd_x86_elf_dtpoff_base
 606   (struct bfd_link_info *);
 607
 608 extern bool _bfd_x86_elf_readonly_dynrelocs
 609   (struct elf_link_hash_entry *, void *);
 610
 611 extern struct elf_link_hash_entry * _bfd_elf_x86_get_local_sym_hash
 612   (struct elf_x86_link_hash_table *, bfd *, const Elf_Internal_Rela *,
 613    bool);
 614
 615 extern hashval_t _bfd_x86_elf_local_htab_hash
 616   (const void *);
 617
 618 extern int _bfd_x86_elf_local_htab_eq
 619   (const void *, const void *);
 620
 621 extern struct bfd_hash_entry * _bfd_x86_elf_link_hash_newfunc
 622   (struct bfd_hash_entry *, struct bfd_hash_table *, const char *);
 623
 624 extern struct bfd_link_hash_table * _bfd_x86_elf_link_hash_table_create
 625   (bfd *);
 626
 627 extern int _bfd_x86_elf_compare_relocs
 628   (const void *, const void *);
 629
 630 extern bool _bfd_x86_elf_link_check_relocs
 631   (bfd *, struct bfd_link_info *);
 632
 633 extern bool _bfd_elf_x86_valid_reloc_p
 634   (asection *, struct bfd_link_info *, struct elf_x86_link_hash_table *,
 635    const Elf_Internal_Rela *, struct elf_link_hash_entry *,
 636    Elf_Internal_Sym *, Elf_Internal_Shdr *, bool *);
 637
 638 extern bool _bfd_x86_elf_size_dynamic_sections
 639   (bfd *, struct bfd_link_info *);
 640
 641 extern struct elf_x86_link_hash_table *_bfd_x86_elf_finish_dynamic_sections
 642   (bfd *, struct bfd_link_info *);
 643
 644 extern bool _bfd_x86_elf_always_size_sections
 645   (bfd *, struct bfd_link_info *);
 646
 647 extern void _bfd_x86_elf_merge_symbol_attribute
 648   (struct elf_link_hash_entry *, unsigned int, bool, bool);
 649
 650 extern void _bfd_x86_elf_copy_indirect_symbol
 651   (struct bfd_link_info *, struct elf_link_hash_entry *,
 652    struct elf_link_hash_entry *);
 653
 654 extern bool _bfd_x86_elf_fixup_symbol
 655   (struct bfd_link_info *, struct elf_link_hash_entry *);
 656
 657 extern bool _bfd_x86_elf_hash_symbol
 658   (struct elf_link_hash_entry *);
 659
 660 extern bool _bfd_x86_elf_adjust_dynamic_symbol
 661   (struct bfd_link_info *, struct elf_link_hash_entry *);
 662
 663 extern void _bfd_x86_elf_hide_symbol
 664   (struct bfd_link_info *, struct elf_link_hash_entry *, bool);
 665
 666 extern bool _bfd_x86_elf_link_symbol_references_local
 667   (struct bfd_link_info *, struct elf_link_hash_entry *);
 668
 669 extern asection * _bfd_x86_elf_gc_mark_hook
 670   (asection *, struct bfd_link_info *, Elf_Internal_Rela *,
 671    struct elf_link_hash_entry *, Elf_Internal_Sym *);
 672
 673 extern long _bfd_x86_elf_get_synthetic_symtab
 674   (bfd *, long, long, bfd_vma, struct elf_x86_plt [], asymbol **,
 675    asymbol **);
 676
 677 extern enum elf_property_kind _bfd_x86_elf_parse_gnu_properties
 678   (bfd *, unsigned int, bfd_byte *, unsigned int);
 679
 680 extern bool _bfd_x86_elf_merge_gnu_properties
 681   (struct bfd_link_info *, bfd *, bfd *, elf_property *, elf_property *);
 682
 683 extern void _bfd_x86_elf_link_fixup_gnu_properties
 684   (struct bfd_link_info *, elf_property_list **);
 685
 686 extern bfd * _bfd_x86_elf_link_setup_gnu_properties
 687   (struct bfd_link_info *, struct elf_x86_init_table *);
 688
 689 extern void _bfd_x86_elf_link_fixup_ifunc_symbol
 690   (struct bfd_link_info *, struct elf_x86_link_hash_table *,
 691    struct elf_link_hash_entry *, Elf_Internal_Sym *sym);
 692
 693 extern void _bfd_x86_elf_link_report_relative_reloc
 694   (struct bfd_link_info *, asection *, struct elf_link_hash_entry *,
 695    Elf_Internal_Sym *, const char *, const void *);
 696
 697 #define bfd_elf64_mkobject \
 698   _bfd_x86_elf_mkobject
 699 #define bfd_elf32_mkobject \
 700   _bfd_x86_elf_mkobject
 701 #define bfd_elf64_bfd_link_hash_table_create \
 702   _bfd_x86_elf_link_hash_table_create
 703 #define bfd_elf32_bfd_link_hash_table_create \
 704   _bfd_x86_elf_link_hash_table_create
 705 #define bfd_elf64_bfd_link_check_relocs \
 706   _bfd_x86_elf_link_check_relocs
 707 #define bfd_elf32_bfd_link_check_relocs \
 708   _bfd_x86_elf_link_check_relocs
 709
 710 #define elf_backend_size_dynamic_sections \
 711   _bfd_x86_elf_size_dynamic_sections
 712 #define elf_backend_always_size_sections \
 713   _bfd_x86_elf_always_size_sections
 714 #define elf_backend_merge_symbol_attribute \
 715   _bfd_x86_elf_merge_symbol_attribute
 716 #define elf_backend_copy_indirect_symbol \
 717   _bfd_x86_elf_copy_indirect_symbol
 718 #define elf_backend_fixup_symbol \
 719   _bfd_x86_elf_fixup_symbol
 720 #define elf_backend_hash_symbol \
 721   _bfd_x86_elf_hash_symbol
 722 #define elf_backend_adjust_dynamic_symbol \
 723   _bfd_x86_elf_adjust_dynamic_symbol
 724 #define elf_backend_gc_mark_hook \
 725   _bfd_x86_elf_gc_mark_hook
 726 #define elf_backend_omit_section_dynsym \
 727   _bfd_elf_omit_section_dynsym_all
 728 #define elf_backend_parse_gnu_properties \
 729   _bfd_x86_elf_parse_gnu_properties
 730 #define elf_backend_merge_gnu_properties \
 731   _bfd_x86_elf_merge_gnu_properties
 732 #define elf_backend_fixup_gnu_properties \
 733   _bfd_x86_elf_link_fixup_gnu_properties
 734
 735 /* Return true if H is a __start_SECNAME/__stop_SECNAME symbol for the
 736    SECNAME section which has been garbage collected by --gc-sections
 737    -z start-stop-gc.  */
 738
 739 static inline bool
 740 elf_x86_start_stop_gc_p (struct bfd_link_info *link_info,
 741                          struct elf_link_hash_entry *h)
 742 {
 743   if (h->start_stop
 744       && link_info->gc_sections
 745       && link_info->start_stop_gc)
 746     {
 747       asection *s = h->root.u.def.section;
 748
 749       do
 750         {
 751           /* Return false if any SECNAME section is kept.  */
 752           if (s->gc_mark)
 753             return false;
 754           s = bfd_get_next_section_by_name (s->owner, s);
 755         }
 756       while (s != NULL);
 757
 758       /* Return true only if all SECNAME sections have been garbage
 759          collected.  */
 760       return true;
 761     }
 762
 763   /* Return false if H isn't a __start_SECNAME/__stop_SECNAME symbol or
 764      --gc-sections or -z start-stop-gc isn't used.  */
 765   return false;
 766 }