bfd/libelf.h

   1 /* BFD back-end data structures for ELF files.
   2    Copyright (C) 1992, 1993 Free Software Foundation, Inc.
   3    Written by Cygnus Support.
   4
   5 This file is part of BFD, the Binary File Descriptor library.
   6
   7 This program is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2 of the License, or
  10 (at your option) any later version.
  11
  12 This program is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with this program; if not, write to the Free Software
  19 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  20
  21 #ifndef _LIBELF_H_
  22 #define _LIBELF_H_ 1
  23
  24 #include "elf/common.h"
  25 #include "elf/internal.h"
  26 #include "elf/external.h"
  27 #include "bfdlink.h"
  28
  29 /* If size isn't specified as 64 or 32, NAME macro should fail.  */
  30 #ifndef NAME
  31 #if ARCH_SIZE==64
  32 #define NAME(x,y) CAT4(x,64,_,y)
  33 #endif
  34 #if ARCH_SIZE==32
  35 #define NAME(x,y) CAT4(x,32,_,y)
  36 #endif
  37 #endif
  38
  39 #ifndef NAME
  40 #define NAME(x,y) CAT4(x,NOSIZE,_,y)
  41 #endif
  42
  43 #define ElfNAME(X)      NAME(Elf,X)
  44 #define elfNAME(X)      NAME(elf,X)
  45
  46 /* Information held for an ELF symbol.  The first field is the
  47    corresponding asymbol.  Every symbol is an ELF file is actually a
  48    pointer to this structure, although it is often handled as a
  49    pointer to an asymbol.  */
  50
  51 typedef struct
  52 {
  53   /* The BFD symbol.  */
  54   asymbol symbol;
  55   /* ELF symbol information.  */
  56   Elf_Internal_Sym internal_elf_sym;
  57   /* Backend specific information.  */
  58   union
  59     {
  60       unsigned int hppa_arg_reloc;
  61       PTR mips_extr;
  62       PTR any;
  63     }
  64   tc_data;
  65 } elf_symbol_type;
  66
  67 /* Constant information held for an ELF backend.  */
  68
  69 struct elf_backend_data
  70 {
  71   /* Whether the backend uses REL or RELA relocations.  FIXME: some
  72      ELF backends use both.  When we need to support one, this whole
  73      approach will need to be changed.  */
  74   int use_rela_p;
  75
  76   /* Whether this backend is 64 bits or not.  FIXME: Who cares?  */
  77   int elf_64_p;
  78
  79   /* The architecture for this backend.  */
  80   enum bfd_architecture arch;
  81
  82   /* The ELF machine code (EM_xxxx) for this backend.  */
  83   int elf_machine_code;
  84
  85   /* The maximum page size for this backend.  */
  86   bfd_vma maxpagesize;
  87
  88   /* This is true if the linker should act like collect and gather
  89      global constructors and destructors by name.  This is true for
  90      MIPS ELF because the Irix 5 tools can not handle the .init
  91      section.  */
  92   boolean collect;
  93
  94   /* A function to translate an ELF RELA relocation to a BFD arelent
  95      structure.  */
  96   void (*elf_info_to_howto) PARAMS ((bfd *, arelent *,
  97                                      Elf_Internal_Rela *));
  98
  99   /* A function to translate an ELF REL relocation to a BFD arelent
 100      structure.  */
 101   void (*elf_info_to_howto_rel) PARAMS ((bfd *, arelent *,
 102                                          Elf_Internal_Rel *));
 103
 104   /* A function to determine whether a symbol is global when
 105      partitioning the symbol table into local and global symbols.
 106      This should be NULL for most targets, in which case the correct
 107      thing will be done.  MIPS ELF, at least on the Irix 5, has
 108      special requirements.  */
 109   boolean (*elf_backend_sym_is_global) PARAMS ((bfd *, asymbol *));
 110
 111   /* The remaining functions are hooks which are called only if they
 112      are not NULL.  */
 113
 114   /* A function to permit a backend specific check on whether a
 115      particular BFD format is relevant for an object file, and to
 116      permit the backend to set any global information it wishes.  When
 117      this is called elf_elfheader is set, but anything else should be
 118      used with caution.  If this returns false, the check_format
 119      routine will return a bfd_error_wrong_format error.  */
 120   boolean (*elf_backend_object_p) PARAMS ((bfd *));
 121
 122   /* A function to do additional symbol processing when reading the
 123      ELF symbol table.  This is where any processor-specific special
 124      section indices are handled.  */
 125   void (*elf_backend_symbol_processing) PARAMS ((bfd *, asymbol *));
 126
 127   /* A function to do additional symbol processing after reading the
 128      entire ELF symbol table.  */
 129   boolean (*elf_backend_symbol_table_processing) PARAMS ((bfd *,
 130                                                           elf_symbol_type *,
 131                                                           int));
 132
 133   /* A function to do additional processing on the ELF section header
 134      just before writing it out.  This is used to set the flags and
 135      type fields for some sections, or to actually write out data for
 136      unusual sections.  */
 137   boolean (*elf_backend_section_processing) PARAMS ((bfd *,
 138                                                      Elf32_Internal_Shdr *));
 139
 140   /* A function to handle unusual section types when creating BFD
 141      sections from ELF sections.  */
 142   boolean (*elf_backend_section_from_shdr) PARAMS ((bfd *,
 143                                                     Elf32_Internal_Shdr *,
 144                                                     char *));
 145
 146   /* A function to set up the ELF section header for a BFD section in
 147      preparation for writing it out.  This is where the flags and type
 148      fields are set for unusual sections.  */
 149   boolean (*elf_backend_fake_sections) PARAMS ((bfd *, Elf32_Internal_Shdr *,
 150                                                 asection *));
 151
 152   /* A function to get the ELF section index for a BFD section.  If
 153      this returns true, the section was found.  If it is a normal ELF
 154      section, *RETVAL should be left unchanged.  If it is not a normal
 155      ELF section *RETVAL should be set to the SHN_xxxx index.  */
 156   boolean (*elf_backend_section_from_bfd_section)
 157     PARAMS ((bfd *, Elf32_Internal_Shdr *, asection *, int *retval));
 158
 159   /* If this field is not NULL, it is called by the add_symbols phase
 160      of a link just before adding a symbol to the global linker hash
 161      table.  It may modify any of the fields as it wishes.  If *NAME
 162      is set to NULL, the symbol will be skipped rather than being
 163      added to the hash table.  This function is responsible for
 164      handling all processor dependent symbol bindings and section
 165      indices, and must set at least *FLAGS and *SEC for each processor
 166      dependent case; failure to do so will cause a link error.  */
 167   boolean (*elf_add_symbol_hook)
 168     PARAMS ((bfd *abfd, struct bfd_link_info *info,
 169              const Elf_Internal_Sym *, const char **name,
 170              flagword *flags, asection **sec, bfd_vma *value));
 171
 172   /* The RELOCATE_SECTION function is called by the ELF backend linker
 173      to handle the relocations for a section.
 174
 175      The relocs are always passed as Rela structures; if the section
 176      actually uses Rel structures, the r_addend field will always be
 177      zero.
 178
 179      This function is responsible for adjust the section contents as
 180      necessary, and (if using Rela relocs and generating a
 181      relocateable output file) adjusting the reloc addend as
 182      necessary.
 183
 184      This function does not have to worry about setting the reloc
 185      address or the reloc symbol index.
 186
 187      LOCAL_SYMS is a pointer to the swapped in local symbols.
 188
 189      LOCAL_SECTIONS is an array giving the section in the input file
 190      corresponding to the st_shndx field of each local symbol.
 191
 192      The global hash table entry for the global symbols can be found
 193      via elf_sym_hashes (input_bfd).
 194
 195      When generating relocateable output, this function must handle
 196      STB_LOCAL/STT_SECTION symbols specially.  The output symbol is
 197      going to be the section symbol corresponding to the output
 198      section, which means that the addend must be adjusted
 199      accordingly.  */
 200   boolean (*elf_backend_relocate_section)
 201     PARAMS ((bfd *output_bfd, struct bfd_link_info *info,
 202              bfd *input_bfd, asection *input_section, bfd_byte *contents,
 203              Elf_Internal_Rela *relocs, Elf_Internal_Sym *local_syms,
 204              asection **local_sections));
 205
 206   /* A function to do any beginning processing needed for the ELF file
 207      before building the ELF headers and computing file positions.  */
 208   void (*elf_backend_begin_write_processing) PARAMS ((bfd *));
 209
 210   /* A function to do any final processing needed for the ELF file
 211      before writing it out.  */
 212   void (*elf_backend_final_write_processing) PARAMS ((bfd *));
 213
 214   /* The swapping table to use when dealing with ECOFF information.
 215      Used for the MIPS ELF .mdebug section.  */
 216   const struct ecoff_debug_swap *elf_backend_ecoff_debug_swap;
 217 };
 218
 219 struct elf_sym_extra
 220 {
 221   int elf_sym_num;              /* sym# after locals/globals are reordered */
 222 };
 223
 224 typedef struct elf_sym_extra Elf_Sym_Extra;
 225
 226 struct bfd_elf_section_data {
 227   Elf_Internal_Shdr this_hdr;
 228   Elf_Internal_Shdr rel_hdr;
 229   int this_idx, rel_idx;
 230   struct elf_link_hash_entry **rel_hashes;
 231 };
 232 #define elf_section_data(sec)  ((struct bfd_elf_section_data*)sec->used_by_bfd)
 233 #define shdr_name(abfd,shdr)    (elf_shstrtab (abfd)->tab + (shdr)->sh_name)
 234
 235 #define get_elf_backend_data(abfd) \
 236   ((struct elf_backend_data *) (abfd)->xvec->backend_data)
 237
 238 struct strtab
 239 {
 240   char *tab;
 241   int nentries;
 242   int length;
 243 };
 244
 245 /* Some private data is stashed away for future use using the tdata pointer
 246    in the bfd structure.  */
 247
 248 struct elf_obj_tdata
 249 {
 250   Elf_Internal_Ehdr elf_header[1];      /* Actual data, but ref like ptr */
 251   Elf_Internal_Shdr **elf_sect_ptr;
 252   Elf_Internal_Phdr *phdr;
 253   struct strtab *strtab_ptr;
 254   int num_locals;
 255   int num_globals;
 256   Elf_Sym_Extra *sym_extra;
 257   asymbol **section_syms;       /* STT_SECTION symbols for each section */
 258   int num_section_syms;         /* number of section_syms allocated */
 259   Elf_Internal_Shdr symtab_hdr;
 260   Elf_Internal_Shdr shstrtab_hdr;
 261   Elf_Internal_Shdr strtab_hdr;
 262   Elf_Internal_Shdr dynsymtab_hdr;
 263   Elf_Internal_Shdr dynstrtab_hdr;
 264   int symtab_section, shstrtab_section, strtab_section, dynsymtab_section;
 265   file_ptr next_file_pos;
 266   void *prstatus;               /* The raw /proc prstatus structure */
 267   void *prpsinfo;               /* The raw /proc prpsinfo structure */
 268   bfd_vma gp;                   /* The gp value (MIPS only, for now) */
 269   int gp_size;                  /* The gp size (MIPS only, for now) */
 270
 271   /* A mapping from external symbols to entries in the linker hash
 272      table, used when linking.  This is indexed by the symbol index
 273      minus the sh_info field of the symbol table header.  */
 274   struct elf_link_hash_entry **sym_hashes;
 275 };
 276
 277 #define elf_tdata(bfd)          ((bfd) -> tdata.elf_obj_data)
 278 #define elf_elfheader(bfd)      (elf_tdata(bfd) -> elf_header)
 279 #define elf_elfsections(bfd)    (elf_tdata(bfd) -> elf_sect_ptr)
 280 #define elf_shstrtab(bfd)       (elf_tdata(bfd) -> strtab_ptr)
 281 #define elf_onesymtab(bfd)      (elf_tdata(bfd) -> symtab_section)
 282 #define elf_dynsymtab(bfd)      (elf_tdata(bfd) -> dynsymtab_section)
 283 #define elf_num_locals(bfd)     (elf_tdata(bfd) -> num_locals)
 284 #define elf_num_globals(bfd)    (elf_tdata(bfd) -> num_globals)
 285 #define elf_sym_extra(bfd)      (elf_tdata(bfd) -> sym_extra)
 286 #define elf_section_syms(bfd)   (elf_tdata(bfd) -> section_syms)
 287 #define elf_num_section_syms(bfd) (elf_tdata(bfd) -> num_section_syms)
 288 #define core_prpsinfo(bfd)      (elf_tdata(bfd) -> prpsinfo)
 289 #define core_prstatus(bfd)      (elf_tdata(bfd) -> prstatus)
 290 #define elf_gp(bfd)             (elf_tdata(bfd) -> gp)
 291 #define elf_gp_size(bfd)        (elf_tdata(bfd) -> gp_size)
 292 #define elf_sym_hashes(bfd)     (elf_tdata(bfd) -> sym_hashes)
 293 \f
 294 /* ELF linker hash table entries.  */
 295
 296 struct elf_link_hash_entry
 297 {
 298   struct bfd_link_hash_entry root;
 299   /* Symbol index in output file.  This is initialized to -1.  It is
 300      set to -2 if the symbol is used by a reloc.  */
 301   long indx;
 302   /* Symbol size.  */
 303   bfd_size_type size;
 304   /* Symbol alignment (common symbols only).  */
 305   unsigned short align;
 306   /* Symbol type (STT_NOTYPE, STT_OBJECT, etc.).  */
 307   char type;
 308 };
 309
 310 /* ELF linker hash table.  */
 311
 312 struct elf_link_hash_table
 313 {
 314   struct bfd_link_hash_table root;
 315 };
 316
 317 /* Look up an entry in an ELF linker hash table.  */
 318
 319 #define elf_link_hash_lookup(table, string, create, copy, follow)       \
 320   ((struct elf_link_hash_entry *)                                       \
 321    bfd_link_hash_lookup (&(table)->root, (string), (create),            \
 322                          (copy), (follow)))
 323
 324 /* Traverse an ELF linker hash table.  */
 325
 326 #define elf_link_hash_traverse(table, func, info)                       \
 327   (bfd_link_hash_traverse                                               \
 328    (&(table)->root,                                                     \
 329     (boolean (*) PARAMS ((struct bfd_link_hash_entry *, PTR))) (func),  \
 330     (info)))
 331
 332 /* Get the ELF linker hash table from a link_info structure.  */
 333
 334 #define elf_hash_table(p) ((struct elf_link_hash_table *) ((p)->hash))
 335 \f
 336 extern char * elf_string_from_elf_section PARAMS ((bfd *, unsigned, unsigned));
 337 extern char * elf_get_str_section PARAMS ((bfd *, unsigned));
 338
 339 #define bfd_elf32_mkobject      bfd_elf_mkobject
 340 #define bfd_elf64_mkobject      bfd_elf_mkobject
 341 #define elf_mkobject            bfd_elf_mkobject
 342
 343 extern unsigned long bfd_elf_hash PARAMS ((CONST unsigned char *));
 344
 345 extern bfd_reloc_status_type bfd_elf_generic_reloc PARAMS ((bfd *,
 346                                                             arelent *,
 347                                                             asymbol *,
 348                                                             PTR,
 349                                                             asection *,
 350                                                             bfd *,
 351                                                             char **));
 352 extern boolean bfd_elf_mkobject PARAMS ((bfd *));
 353 extern Elf_Internal_Shdr *bfd_elf_find_section PARAMS ((bfd *, char *));
 354
 355 extern struct bfd_link_hash_table *_bfd_elf_link_hash_table_create
 356   PARAMS ((bfd *));
 357
 358 extern boolean bfd_elf32_write_object_contents PARAMS ((bfd *));
 359 extern boolean bfd_elf64_write_object_contents PARAMS ((bfd *));
 360
 361 extern bfd_target *bfd_elf32_object_p PARAMS ((bfd *));
 362 extern bfd_target *bfd_elf32_core_file_p PARAMS ((bfd *));
 363 extern char *bfd_elf32_core_file_failing_command PARAMS ((bfd *));
 364 extern int bfd_elf32_core_file_failing_signal PARAMS ((bfd *));
 365 extern boolean bfd_elf32_core_file_matches_executable_p PARAMS ((bfd *,
 366                                                                  bfd *));
 367 extern boolean bfd_elf32_set_section_contents PARAMS ((bfd *, sec_ptr, PTR,
 368                                                        file_ptr,
 369                                                        bfd_size_type));
 370
 371 extern long bfd_elf32_get_symtab_upper_bound PARAMS ((bfd *));
 372 extern long bfd_elf32_get_symtab PARAMS ((bfd *, asymbol **));
 373 extern long bfd_elf32_get_dynamic_symtab_upper_bound PARAMS ((bfd *));
 374 extern long bfd_elf32_canonicalize_dynamic_symtab PARAMS ((bfd *, asymbol **));
 375 extern long bfd_elf32_get_reloc_upper_bound PARAMS ((bfd *, sec_ptr));
 376 extern long bfd_elf32_canonicalize_reloc PARAMS ((bfd *, sec_ptr,
 377                                                   arelent **, asymbol **));
 378 extern asymbol *bfd_elf32_make_empty_symbol PARAMS ((bfd *));
 379 extern void bfd_elf32_print_symbol PARAMS ((bfd *, PTR, asymbol *,
 380                                             bfd_print_symbol_type));
 381 extern void bfd_elf32_get_symbol_info PARAMS ((bfd *, asymbol *,
 382                                                symbol_info *));
 383 extern alent *bfd_elf32_get_lineno PARAMS ((bfd *, asymbol *));
 384 extern boolean bfd_elf32_set_arch_mach PARAMS ((bfd *, enum bfd_architecture,
 385                                                 unsigned long));
 386 extern boolean bfd_elf32_find_nearest_line PARAMS ((bfd *, asection *,
 387                                                     asymbol **,
 388                                                     bfd_vma, CONST char **,
 389                                                     CONST char **,
 390                                                     unsigned int *));
 391 extern int bfd_elf32_sizeof_headers PARAMS ((bfd *, boolean));
 392 extern void bfd_elf32__write_relocs PARAMS ((bfd *, asection *, PTR));
 393 extern boolean bfd_elf32_new_section_hook PARAMS ((bfd *, asection *));
 394 extern boolean bfd_elf32_bfd_link_add_symbols
 395   PARAMS ((bfd *, struct bfd_link_info *));
 396 extern boolean bfd_elf32_bfd_final_link
 397   PARAMS ((bfd *, struct bfd_link_info *));
 398
 399 /* If the target doesn't have reloc handling written yet:  */
 400 extern void bfd_elf32_no_info_to_howto PARAMS ((bfd *, arelent *,
 401                                                 Elf32_Internal_Rela *));
 402
 403 extern bfd_target *bfd_elf64_object_p PARAMS ((bfd *));
 404 extern bfd_target *bfd_elf64_core_file_p PARAMS ((bfd *));
 405 extern char *bfd_elf64_core_file_failing_command PARAMS ((bfd *));
 406 extern int bfd_elf64_core_file_failing_signal PARAMS ((bfd *));
 407 extern boolean bfd_elf64_core_file_matches_executable_p PARAMS ((bfd *,
 408                                                                  bfd *));
 409 extern boolean bfd_elf64_set_section_contents PARAMS ((bfd *, sec_ptr, PTR,
 410                                                        file_ptr,
 411                                                        bfd_size_type));
 412
 413 extern long bfd_elf64_get_symtab_upper_bound PARAMS ((bfd *));
 414 extern long bfd_elf64_get_symtab PARAMS ((bfd *, asymbol **));
 415 extern long bfd_elf64_get_dynamic_symtab_upper_bound PARAMS ((bfd *));
 416 extern long bfd_elf64_canonicalize_dynamic_symtab PARAMS ((bfd *, asymbol **));
 417 extern long bfd_elf64_get_reloc_upper_bound PARAMS ((bfd *, sec_ptr));
 418 extern long bfd_elf64_canonicalize_reloc PARAMS ((bfd *, sec_ptr,
 419                                                   arelent **, asymbol **));
 420 extern asymbol *bfd_elf64_make_empty_symbol PARAMS ((bfd *));
 421 extern void bfd_elf64_print_symbol PARAMS ((bfd *, PTR, asymbol *,
 422                                             bfd_print_symbol_type));
 423 extern void bfd_elf64_get_symbol_info PARAMS ((bfd *, asymbol *,
 424                                                symbol_info *));
 425 extern alent *bfd_elf64_get_lineno PARAMS ((bfd *, asymbol *));
 426 extern boolean bfd_elf64_set_arch_mach PARAMS ((bfd *, enum bfd_architecture,
 427                                                 unsigned long));
 428 extern boolean bfd_elf64_find_nearest_line PARAMS ((bfd *, asection *,
 429                                                     asymbol **,
 430                                                     bfd_vma, CONST char **,
 431                                                     CONST char **,
 432                                                     unsigned int *));
 433 extern int bfd_elf64_sizeof_headers PARAMS ((bfd *, boolean));
 434 extern void bfd_elf64__write_relocs PARAMS ((bfd *, asection *, PTR));
 435 extern boolean bfd_elf64_new_section_hook PARAMS ((bfd *, asection *));
 436 extern boolean bfd_elf64_bfd_link_add_symbols
 437   PARAMS ((bfd *, struct bfd_link_info *));
 438 extern boolean bfd_elf64_bfd_final_link
 439   PARAMS ((bfd *, struct bfd_link_info *));
 440
 441 /* If the target doesn't have reloc handling written yet:  */
 442 extern void bfd_elf64_no_info_to_howto PARAMS ((bfd *, arelent *,
 443                                                 Elf64_Internal_Rela *));
 444
 445 #endif /* _LIBELF_H_ */