include/libc-symbols.h

   1 /* Support macros for making weak and strong aliases for symbols,
   2    and for using symbol sets and linker warnings with GNU ld.
   3    Copyright (C) 1995-1998,2000-2003,2004 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library 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 GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #ifndef _LIBC_SYMBOLS_H
  22 #define _LIBC_SYMBOLS_H 1
  23
  24 /* This file's macros are included implicitly in the compilation of every
  25    file in the C library by -imacros.
  26
  27    We include config.h which is generated by configure.
  28    It should define for us the following symbols:
  29
  30    * HAVE_ASM_SET_DIRECTIVE if we have `.set B, A' instead of `A = B'.
  31    * ASM_GLOBAL_DIRECTIVE with `.globl' or `.global'.
  32    * ASM_TYPE_DIRECTIVE_PREFIX with `@' or `#' or whatever for .type,
  33      or leave it undefined if there is no .type directive.
  34    * HAVE_GNU_LD if using GNU ld, with support for weak symbols in a.out,
  35    and for symbol set and warning messages extensions in a.out and ELF.
  36    * HAVE_ELF if using ELF, which supports weak symbols using `.weak'.
  37    * HAVE_ASM_WEAK_DIRECTIVE if we have weak symbols using `.weak'.
  38    * HAVE_ASM_WEAKEXT_DIRECTIVE if we have weak symbols using `.weakext'.
  39
  40    */
  41
  42 /* This is defined for the compilation of all C library code.  features.h
  43    tests this to avoid inclusion of stubs.h while compiling the library,
  44    before stubs.h has been generated.  Some library code that is shared
  45    with other packages also tests this symbol to see if it is being
  46    compiled as part of the C library.  We must define this before including
  47    config.h, because it makes some definitions conditional on whether libc
  48    itself is being compiled, or just some generator program.  */
  49 #define _LIBC   1
  50
  51 /* Enable declarations of GNU extensions, since we are compiling them.  */
  52 #define _GNU_SOURCE     1
  53 /* And we also need the data for the reentrant functions.  */
  54 #define _REENTRANT      1
  55
  56 #include <config.h>
  57
  58 /* The symbols in all the user (non-_) macros are C symbols.
  59    HAVE_GNU_LD without HAVE_ELF implies a.out.  */
  60
  61 #if defined HAVE_ASM_WEAK_DIRECTIVE || defined HAVE_ASM_WEAKEXT_DIRECTIVE
  62 # define HAVE_WEAK_SYMBOLS
  63 #endif
  64
  65 #ifndef __SYMBOL_PREFIX
  66 # ifdef NO_UNDERSCORES
  67 #  define __SYMBOL_PREFIX
  68 # else
  69 #  define __SYMBOL_PREFIX "_"
  70 # endif
  71 #endif
  72
  73 #ifndef C_SYMBOL_NAME
  74 # ifdef NO_UNDERSCORES
  75 #  define C_SYMBOL_NAME(name) name
  76 # else
  77 #  define C_SYMBOL_NAME(name) _##name
  78 # endif
  79 #endif
  80
  81 #ifndef ASM_LINE_SEP
  82 # define ASM_LINE_SEP ;
  83 #endif
  84
  85 #ifdef HAVE_ASM_GLOBAL_DOT_NAME
  86 # ifndef C_SYMBOL_DOT_NAME
  87 #  if defined __GNUC__ && defined __GNUC_MINOR__ \
  88       && (__GNUC__ << 16) + __GNUC_MINOR__ >= (3 << 16) + 1
  89 #   define C_SYMBOL_DOT_NAME(name) .name
  90 #  else
  91 #   define C_SYMBOL_DOT_NAME(name) .##name
  92 #  endif
  93 # endif
  94 #endif
  95
  96 #ifndef __ASSEMBLER__
  97 /* GCC understands weak symbols and aliases; use its interface where
  98    possible, instead of embedded assembly language.  */
  99
 100 /* Define ALIASNAME as a strong alias for NAME.  */
 101 # define strong_alias(name, aliasname) _strong_alias(name, aliasname)
 102 # define _strong_alias(name, aliasname) \
 103   extern __typeof (name) aliasname __attribute__ ((alias (#name)));
 104
 105 /* This comes between the return type and function name in
 106    a function definition to make that definition weak.  */
 107 # define weak_function __attribute__ ((weak))
 108 # define weak_const_function __attribute__ ((weak, __const__))
 109
 110 # ifdef HAVE_WEAK_SYMBOLS
 111
 112 /* Define ALIASNAME as a weak alias for NAME.
 113    If weak aliases are not available, this defines a strong alias.  */
 114 #  define weak_alias(name, aliasname) _weak_alias (name, aliasname)
 115 #  define _weak_alias(name, aliasname) \
 116   extern __typeof (name) aliasname __attribute__ ((weak, alias (#name)));
 117
 118 /* Declare SYMBOL as weak undefined symbol (resolved to 0 if not defined).  */
 119 #  define weak_extern(symbol) _weak_extern (weak symbol)
 120 #  define _weak_extern(expr) _Pragma (#expr)
 121
 122 # else
 123
 124 #  define weak_alias(name, aliasname) strong_alias(name, aliasname)
 125 #  define weak_extern(symbol) /* Nothing. */
 126
 127 # endif
 128
 129 #else /* __ASSEMBLER__ */
 130
 131 # ifdef HAVE_ASM_SET_DIRECTIVE
 132 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 133 #   define strong_alias(original, alias)                                \
 134   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 135   .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original) ASM_LINE_SEP      \
 136   ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP           \
 137   .set C_SYMBOL_DOT_NAME (alias),C_SYMBOL_DOT_NAME (original)
 138 #   define strong_data_alias(original, alias)                           \
 139   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 140   .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original)
 141 #  else
 142 #   define strong_alias(original, alias)                                \
 143   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 144   .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original)
 145 #   define strong_data_alias(original, alias) strong_alias(original, alias)
 146 #  endif
 147 # else
 148 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 149 #   define strong_alias(original, alias)                                \
 150   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 151   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original) ASM_LINE_SEP         \
 152   ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP           \
 153   C_SYMBOL_DOT_NAME (alias) = C_SYMBOL_DOT_NAME (original)
 154 #   define strong_data_alias(original, alias)                           \
 155   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 156   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
 157 #  else
 158 #   define strong_alias(original, alias)                                \
 159   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 160   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
 161 #   define strong_data_alias(original, alias) strong_alias(original, alias)
 162 #  endif
 163 # endif
 164
 165 # ifdef HAVE_WEAK_SYMBOLS
 166 #  ifdef HAVE_ASM_WEAKEXT_DIRECTIVE
 167 #   ifdef HAVE_ASM_GLOBAL_DOT_NAME
 168 #    define weak_alias(original, alias)                                 \
 169   .weakext C_SYMBOL_NAME (alias), C_SYMBOL_NAME (original) ASM_LINE_SEP \
 170   .weakext C_SYMBOL_DOT_NAME (alias), C_SYMBOL_DOT_NAME (original)
 171 #   else
 172 #    define weak_alias(original, alias)                                 \
 173   .weakext C_SYMBOL_NAME (alias), C_SYMBOL_NAME (original)
 174 #   endif
 175 #   define weak_extern(symbol)                                          \
 176   .weakext C_SYMBOL_NAME (symbol)
 177
 178 #  else /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
 179
 180 #   ifdef HAVE_ASM_GLOBAL_DOT_NAME
 181 #    define weak_alias(original, alias)                                 \
 182   .weak C_SYMBOL_NAME (alias) ASM_LINE_SEP                              \
 183   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original) ASM_LINE_SEP         \
 184   .weak C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP                          \
 185   C_SYMBOL_DOT_NAME (alias) = C_SYMBOL_DOT_NAME (original)
 186 #   else
 187 #    define weak_alias(original, alias)                                 \
 188   .weak C_SYMBOL_NAME (alias) ASM_LINE_SEP                              \
 189   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
 190 #   endif
 191
 192 #   define weak_extern(symbol)                                          \
 193   .weak C_SYMBOL_NAME (symbol)
 194
 195 #  endif /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
 196
 197 # else /* ! HAVE_WEAK_SYMBOLS */
 198
 199 #  define weak_alias(original, alias) strong_alias(original, alias)
 200 #  define weak_extern(symbol) /* Nothing */
 201 # endif /* ! HAVE_WEAK_SYMBOLS */
 202
 203 #endif /* __ASSEMBLER__ */
 204
 205 /* On some platforms we can make internal function calls (i.e., calls of
 206    functions not exported) a bit faster by using a different calling
 207    convention.  */
 208 #ifndef internal_function
 209 # define internal_function      /* empty */
 210 #endif
 211
 212 /* Prepare for the case that `__builtin_expect' is not available.  */
 213 #ifndef HAVE_BUILTIN_EXPECT
 214 # define __builtin_expect(expr, val) (expr)
 215 #endif
 216
 217 /* Determine the return address.  */
 218 #define RETURN_ADDRESS(nr) \
 219   __builtin_extract_return_addr (__builtin_return_address (nr))
 220
 221 /* When a reference to SYMBOL is encountered, the linker will emit a
 222    warning message MSG.  */
 223 #ifdef HAVE_GNU_LD
 224 # ifdef HAVE_ELF
 225
 226 /* We want the .gnu.warning.SYMBOL section to be unallocated.  */
 227 #  ifdef HAVE_ASM_PREVIOUS_DIRECTIVE
 228 #   define __make_section_unallocated(section_string)   \
 229   asm (".section " section_string "\n\t.previous");
 230 #  elif defined HAVE_ASM_POPSECTION_DIRECTIVE
 231 #   define __make_section_unallocated(section_string)   \
 232   asm (".pushsection " section_string "\n\t.popsection");
 233 #  else
 234 #   define __make_section_unallocated(section_string)
 235 #  endif
 236
 237 /* Tacking on "\n\t#" to the section name makes gcc put it's bogus
 238    section attributes on what looks like a comment to the assembler.  */
 239 #  ifdef HAVE_SECTION_QUOTES
 240 #   define __sec_comment "\"\n\t#\""
 241 #  else
 242 #   define __sec_comment "\n\t#"
 243 #  endif
 244 #  define link_warning(symbol, msg) \
 245   __make_section_unallocated (".gnu.warning." #symbol) \
 246   static const char __evoke_link_warning_##symbol[]     \
 247     __attribute__ ((used, section (".gnu.warning." #symbol __sec_comment))) \
 248     = msg;
 249 #  define libc_freeres_ptr(decl) \
 250   __make_section_unallocated ("__libc_freeres_ptrs, \"aw\", %nobits") \
 251   decl __attribute__ ((section ("__libc_freeres_ptrs" __sec_comment)))
 252 #  define __libc_freeres_fn_section \
 253   __attribute__ ((section ("__libc_freeres_fn")))
 254 # else /* Not ELF: a.out */
 255 #  ifdef HAVE_XCOFF
 256 /* XCOFF does not support .stabs.
 257    The native aix linker will remove the .stab and .stabstr sections
 258    The gnu linker will have a fatal error if there is a relocation for
 259    symbol in the .stab section.  Silently disable this macro.  */
 260 #   define link_warning(symbol, msg)
 261 #  else
 262 #   define link_warning(symbol, msg)            \
 263      asm (".stabs \"" msg "\",30,0,0,0\n\t"     \
 264           ".stabs \"" __SYMBOL_PREFIX #symbol "\",1,0,0,0\n");
 265 #  endif /* XCOFF */
 266 #  define libc_freeres_ptr(decl) decl
 267 #  define __libc_freeres_fn_section
 268 # endif
 269 #else
 270 /* We will never be heard; they will all die horribly.  */
 271 # define link_warning(symbol, msg)
 272 # define libc_freeres_ptr(decl) decl
 273 # define __libc_freeres_fn_section
 274 #endif
 275 #define libc_freeres_fn(name)   \
 276   static void name (void) __attribute_used__ __libc_freeres_fn_section; \
 277   text_set_element (__libc_subfreeres, name);                           \
 278   static void name (void)
 279
 280 /* A canned warning for sysdeps/stub functions.  */
 281 #define stub_warning(name) \
 282   link_warning (name, \
 283                 "warning: " #name " is not implemented and will always fail")
 284
 285 /* Warning for linking functions calling dlopen into static binaries.  */
 286 #ifdef SHARED
 287 #define static_link_warning(name)
 288 #else
 289 #define static_link_warning(name) static_link_warning1(name)
 290 #define static_link_warning1(name) \
 291   link_warning(name, "Using '" #name "' in statically linked applications \
 292 requires at runtime the shared libraries from the glibc version used \
 293 for linking")
 294 #endif
 295
 296 /* Declare SYMBOL to be TYPE (`function' or `object') and of SIZE bytes,
 297    when the assembler supports such declarations (such as in ELF).
 298    This is only necessary when defining something in assembly, or playing
 299    funny alias games where the size should be other than what the compiler
 300    thinks it is.  */
 301 #define declare_symbol(symbol, type, size) \
 302   declare_symbol_1 (symbol, type, size)
 303 #ifdef ASM_TYPE_DIRECTIVE_PREFIX
 304 # ifdef __ASSEMBLER__
 305 #  define declare_symbol_1(symbol, type, size) \
 306     .type C_SYMBOL_NAME (symbol), \
 307           declare_symbol_1_paste (ASM_TYPE_DIRECTIVE_PREFIX, type), size
 308 #  define declare_symbol_1_paste(a, b)  declare_symbol_1_paste_1 (a,b)
 309 #  define declare_symbol_1_paste_1(a,b) a##b
 310 # else /* Not __ASSEMBLER__.  */
 311 #  define declare_symbol_1(symbol, type, size) \
 312     asm (".type " __SYMBOL_PREFIX #symbol ", " \
 313          declare_symbol_1_stringify (ASM_TYPE_DIRECTIVE_PREFIX) #type \
 314          "\n\t.size " __SYMBOL_PREFIX #symbol ", " #size);
 315 #  define declare_symbol_1_stringify(x) declare_symbol_1_stringify_1 (x)
 316 #  define declare_symbol_1_stringify_1(x) #x
 317 # endif /* __ASSEMBLER__ */
 318 #else
 319 # define declare_symbol_1(symbol, type, size) /* Nothing.  */
 320 #endif
 321
 322
 323 /*
 324 \f
 325 */
 326
 327 #ifdef HAVE_GNU_LD
 328
 329 /* Symbol set support macros.  */
 330
 331 # ifdef HAVE_ELF
 332
 333 /* Make SYMBOL, which is in the text segment, an element of SET.  */
 334 #  define text_set_element(set, symbol) _elf_set_element(set, symbol)
 335 /* Make SYMBOL, which is in the data segment, an element of SET.  */
 336 #  define data_set_element(set, symbol) _elf_set_element(set, symbol)
 337 /* Make SYMBOL, which is in the bss segment, an element of SET.  */
 338 #  define bss_set_element(set, symbol)  _elf_set_element(set, symbol)
 339
 340 /* These are all done the same way in ELF.
 341    There is a new section created for each set.  */
 342 #  ifdef SHARED
 343 /* When building a shared library, make the set section writable,
 344    because it will need to be relocated at run time anyway.  */
 345 #   define _elf_set_element(set, symbol) \
 346   static const void *__elf_set_##set##_element_##symbol##__ \
 347     __attribute__ ((used, section (#set))) = &(symbol)
 348 #  else
 349 #   define _elf_set_element(set, symbol) \
 350   static const void *const __elf_set_##set##_element_##symbol##__ \
 351     __attribute__ ((used, section (#set))) = &(symbol)
 352 #  endif
 353
 354 /* Define SET as a symbol set.  This may be required (it is in a.out) to
 355    be able to use the set's contents.  */
 356 #  define symbol_set_define(set)        symbol_set_declare(set)
 357
 358 /* Declare SET for use in this module, if defined in another module.
 359    In a shared library, this is always local to that shared object.
 360    For static linking, the set might be wholly absent and so we use
 361    weak references.  */
 362 #  define symbol_set_declare(set) \
 363   extern char const __start_##set[] __symbol_set_attribute; \
 364   extern char const __stop_##set[] __symbol_set_attribute;
 365 #  ifdef SHARED
 366 #   define __symbol_set_attribute attribute_hidden
 367 #  else
 368 #   define __symbol_set_attribute __attribute__ ((weak))
 369 #  endif
 370
 371 /* Return a pointer (void *const *) to the first element of SET.  */
 372 #  define symbol_set_first_element(set) ((void *const *) (&__start_##set))
 373
 374 /* Return true iff PTR (a void *const *) has been incremented
 375    past the last element in SET.  */
 376 #  define symbol_set_end_p(set, ptr) ((ptr) >= (void *const *) &__stop_##set)
 377
 378 # else  /* Not ELF: a.out.  */
 379
 380 #  ifdef HAVE_XCOFF
 381 /* XCOFF does not support .stabs.
 382    The native aix linker will remove the .stab and .stabstr sections
 383    The gnu linker will have a fatal error if there is a relocation for
 384    symbol in the .stab section.  Silently disable these macros.  */
 385 #   define text_set_element(set, symbol)
 386 #   define data_set_element(set, symbol)
 387 #   define bss_set_element(set, symbol)
 388 #  else
 389 #   define text_set_element(set, symbol)        \
 390     asm (".stabs \"" __SYMBOL_PREFIX #set "\",23,0,0," __SYMBOL_PREFIX #symbol)
 391 #   define data_set_element(set, symbol)        \
 392     asm (".stabs \"" __SYMBOL_PREFIX #set "\",25,0,0," __SYMBOL_PREFIX #symbol)
 393 #   define bss_set_element(set, symbol) ?error Must use initialized data.
 394 #  endif /* XCOFF */
 395 #  define symbol_set_define(set)        void *const (set)[1];
 396 #  define symbol_set_declare(set)       extern void *const (set)[1];
 397
 398 #  define symbol_set_first_element(set) &(set)[1]
 399 #  define symbol_set_end_p(set, ptr)    (*(ptr) == 0)
 400
 401 # endif /* ELF.  */
 402 #else
 403 /* We cannot do anything in generial.  */
 404 # define text_set_element(set, symbol) asm ("")
 405 # define data_set_element(set, symbol) asm ("")
 406 # define bss_set_element(set, symbol) asm ("")
 407 # define symbol_set_define(set)         void *const (set)[1];
 408 # define symbol_set_declare(set)        extern void *const (set)[1];
 409
 410 # define symbol_set_first_element(set)  &(set)[1]
 411 # define symbol_set_end_p(set, ptr)     (*(ptr) == 0)
 412 #endif  /* Have GNU ld.  */
 413
 414 #if DO_VERSIONING
 415 # define symbol_version(real, name, version) \
 416      _symbol_version(real, name, version)
 417 # define default_symbol_version(real, name, version) \
 418      _default_symbol_version(real, name, version)
 419 # ifdef __ASSEMBLER__
 420 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 421 #   define _symbol_version(real, name, version) \
 422      .symver real, name##@##version ASM_LINE_SEP                        \
 423      .symver C_SYMBOL_DOT_NAME(real), C_SYMBOL_DOT_NAME(name##@##version)
 424 #   define _default_symbol_version(real, name, version) \
 425      .symver real, name##@##@##version ASM_LINE_SEP                     \
 426      .symver C_SYMBOL_DOT_NAME(real), C_SYMBOL_DOT_NAME(name##@##@##version)
 427 #  else
 428 #   define _symbol_version(real, name, version) \
 429      .symver real, name##@##version
 430 #   define _default_symbol_version(real, name, version) \
 431      .symver real, name##@##@##version
 432 #  endif
 433 # else
 434 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 435 #   define _symbol_version(real, name, version) \
 436      __asm__ (".symver " #real "," #name "@" #version "\n\t"    \
 437               ".symver ." #real ",." #name "@" #version)
 438 #   define _default_symbol_version(real, name, version) \
 439      __asm__ (".symver " #real "," #name "@@" #version "\n\t"   \
 440               ".symver ." #real ",." #name "@@" #version)
 441 #  else
 442 #   define _symbol_version(real, name, version) \
 443      __asm__ (".symver " #real "," #name "@" #version)
 444 #   define _default_symbol_version(real, name, version) \
 445      __asm__ (".symver " #real "," #name "@@" #version)
 446 #  endif
 447 # endif
 448 #else
 449 # define symbol_version(real, name, version)
 450 # define default_symbol_version(real, name, version) \
 451   strong_alias(real, name)
 452 #endif
 453
 454 #if defined HAVE_VISIBILITY_ATTRIBUTE \
 455     && (defined SHARED || defined LIBC_NONSHARED)
 456 # define attribute_hidden __attribute__ ((visibility ("hidden")))
 457 #else
 458 # define attribute_hidden
 459 #endif
 460
 461 #ifdef HAVE_TLS_MODEL_ATTRIBUTE
 462 # define attribute_tls_model_ie __attribute__ ((tls_model ("initial-exec")))
 463 #else
 464 # define attribute_tls_model_ie
 465 #endif
 466
 467 #ifdef HAVE_Z_RELRO
 468 # define attribute_relro __attribute__ ((section (".data.rel.ro")))
 469 #else
 470 # define attribute_relro
 471 #endif
 472
 473 /* Handling on non-exported internal names.  We have to do this only
 474    for shared code.  */
 475 #ifdef SHARED
 476 # define INTUSE(name) name##_internal
 477 # define INTDEF(name) strong_alias (name, name##_internal)
 478 # define INTVARDEF(name) \
 479   _INTVARDEF (name, name##_internal)
 480 # if defined HAVE_VISIBILITY_ATTRIBUTE
 481 #  define _INTVARDEF(name, aliasname) \
 482   extern __typeof (name) aliasname __attribute__ ((alias (#name), \
 483                                                    visibility ("hidden")));
 484 # else
 485 #  define _INTVARDEF(name, aliasname) \
 486   extern __typeof (name) aliasname __attribute__ ((alias (#name)));
 487 # endif
 488 # define INTDEF2(name, newname) strong_alias (name, newname##_internal)
 489 # define INTVARDEF2(name, newname) _INTVARDEF (name, newname##_internal)
 490 #else
 491 # define INTUSE(name) name
 492 # define INTDEF(name)
 493 # define INTVARDEF(name)
 494 # define INTDEF2(name, newname)
 495 # define INTVARDEF2(name, newname)
 496 #endif
 497
 498 /* The following macros are used for PLT bypassing within libc.so
 499    (and if needed other libraries similarly).
 500    First of all, you need to have the function prototyped somewhere,
 501    say in foo/foo.h:
 502
 503    int foo (int __bar);
 504
 505    If calls to foo within libc.so should always go to foo defined in libc.so,
 506    then in include/foo.h you add:
 507
 508    libc_hidden_proto (foo)
 509
 510    line and after the foo function definition:
 511
 512    int foo (int __bar)
 513    {
 514      return __bar;
 515    }
 516    libc_hidden_def (foo)
 517
 518    or
 519
 520    int foo (int __bar)
 521    {
 522      return __bar;
 523    }
 524    libc_hidden_weak (foo)
 525
 526    Simularly for global data. If references to foo within libc.so should
 527    always go to foo defined in libc.so, then in include/foo.h you add:
 528
 529    libc_hidden_proto (foo)
 530
 531    line and after foo's definition:
 532
 533    int foo = INITIAL_FOO_VALUE;
 534    libc_hidden_data_def (foo)
 535
 536    or
 537
 538    int foo = INITIAL_FOO_VALUE;
 539    libc_hidden_data_weak (foo)
 540
 541    If foo is normally just an alias (strong or weak) of some other function,
 542    you should use the normal strong_alias first, then add libc_hidden_def
 543    or libc_hidden_weak:
 544
 545    int baz (int __bar)
 546    {
 547      return __bar;
 548    }
 549    strong_alias (baz, foo)
 550    libc_hidden_weak (foo)
 551
 552    If the function should be internal to multiple objects, say ld.so and
 553    libc.so, the best way is to use:
 554
 555    #if !defined NOT_IN_libc || defined IS_IN_rtld
 556    hidden_proto (foo)
 557    #endif
 558
 559    in include/foo.h and the normal macros at all function definitions
 560    depending on what DSO they belong to.
 561
 562    If versioned_symbol macro is used to define foo,
 563    libc_hidden_ver macro should be used, as in:
 564
 565    int __real_foo (int __bar)
 566    {
 567      return __bar;
 568    }
 569    versioned_symbol (libc, __real_foo, foo, GLIBC_2_1);
 570    libc_hidden_ver (__real_foo, foo)  */
 571
 572 #if defined SHARED && defined DO_VERSIONING \
 573     && !defined HAVE_BROKEN_ALIAS_ATTRIBUTE && !defined NO_HIDDEN
 574 # ifndef __ASSEMBLER__
 575 #  if !defined HAVE_VISIBILITY_ATTRIBUTE \
 576       || defined HAVE_BROKEN_VISIBILITY_ATTRIBUTE
 577 #   define __hidden_proto_hiddenattr(attrs...)
 578 #  else
 579 #   define __hidden_proto_hiddenattr(attrs...) \
 580   __attribute__ ((visibility ("hidden"), ##attrs))
 581 #  endif
 582 #  define hidden_proto(name, attrs...) \
 583   __hidden_proto (name, __GI_##name, ##attrs)
 584 #  define __hidden_proto(name, internal, attrs...) \
 585   extern __typeof (name) internal; \
 586   extern __typeof (name) name __asm__ (__hidden_asmname (#internal)) \
 587   __hidden_proto_hiddenattr (attrs);
 588 #  define __hidden_asmname(name) \
 589   __hidden_asmname1 (__USER_LABEL_PREFIX__, name)
 590 #  define __hidden_asmname1(prefix, name) __hidden_asmname2(prefix, name)
 591 #  define __hidden_asmname2(prefix, name) #prefix name
 592 #  ifdef HAVE_ASM_SET_DIRECTIVE
 593 #   define __hidden_def1(original, alias)                       \
 594   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP       \
 595   .set C_SYMBOL_NAME (alias), C_SYMBOL_NAME (original)
 596 #   ifdef HAVE_ASM_GLOBAL_DOT_NAME
 597 #     define __hidden_dot_def1(original, alias)  ASM_LINE_SEP   \
 598   ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP   \
 599   .set C_SYMBOL_DOT_NAME (alias), C_SYMBOL_DOT_NAME (original)
 600 #   else
 601 #     define __hidden_dot_def1(original, alias)
 602 #   endif
 603 #  else
 604 #   define __hidden_def1(original, alias)                       \
 605   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP       \
 606   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
 607 #   ifdef HAVE_ASM_GLOBAL_DOT_NAME
 608 #    define __hidden_dot_def1(original, alias)  ASM_LINE_SEP    \
 609   ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP   \
 610   C_SYMBOL_DOT_NAME (alias) = C_SYMBOL_DOT_NAME (original)
 611 #   else
 612 #    define __hidden_dot_def1(original, alias)
 613 #   endif
 614 #  endif
 615 #  define __hidden_def2(...) #__VA_ARGS__
 616 #  define __hidden_def3(...) __hidden_def2 (__VA_ARGS__)
 617 #  define hidden_def(name)                                      \
 618   __asm__ (__hidden_def3 (__hidden_def1 (__GI_##name, name) \
 619   __hidden_dot_def1 (__GI_##name, name)));
 620 #  define hidden_data_def(name)                                 \
 621   __asm__ (__hidden_def3 (__hidden_def1 (__GI_##name, name)));
 622 #  define hidden_ver(local, name)                               \
 623   __asm__ (__hidden_def3 (__hidden_def1 (local, __GI_##name) \
 624   __hidden_dot_def1 (local, __GI_##name)));
 625 #  define hidden_data_ver(local, name)                          \
 626   __asm__ (__hidden_def3 (__hidden_def1 (local, __GI_##name)));
 627 #  ifdef HAVE_WEAK_SYMBOLS
 628 #   ifdef HAVE_ASM_WEAKEXT_DIRECTIVE
 629 #    define __hidden_weak1(original, alias)                     \
 630   .weakext C_SYMBOL_NAME (alias), C_SYMBOL_NAME (original)
 631 #    ifdef HAVE_ASM_GLOBAL_DOT_NAME
 632 #     define __hidden_dot_weak1(original, alias)        ASM_LINE_SEP    \
 633   .weakext C_SYMBOL_DOT_NAME (alias), C_SYMBOL_DOT_NAME (original)
 634 #    else
 635 #     define __hidden_dot_weak1(original, alias)
 636 #    endif
 637 #   else /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
 638 #    define __hidden_weak1(original, alias)                     \
 639   .weak C_SYMBOL_NAME (alias) ASM_LINE_SEP                      \
 640   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
 641 #    ifdef HAVE_ASM_GLOBAL_DOT_NAME
 642 #     define __hidden_dot_weak1(original, alias)        ASM_LINE_SEP    \
 643   .weak C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP  \
 644   C_SYMBOL_DOT_NAME (alias) = C_SYMBOL_DOT_NAME (original)
 645 #    else
 646 #     define __hidden_dot_weak1(original, alias)
 647 #    endif
 648 #   endif
 649 #   define hidden_weak(name)                                    \
 650   __asm__ (__hidden_def3 (__hidden_weak1 (__GI_##name, name) \
 651   __hidden_dot_weak1 (__GI_##name, name)));
 652 #   define hidden_data_weak(name)                                       \
 653   __asm__ (__hidden_def3 (__hidden_weak1 (__GI_##name, name)));
 654 #  else
 655 #   define hidden_weak(name) hidden_def (name)
 656 #  endif
 657 # else
 658 /* For assembly, we need to do the opposite of what we do in C:
 659    in assembly gcc __REDIRECT stuff is not in place, so functions
 660    are defined by its normal name and we need to create the
 661    __GI_* alias to it, in C __REDIRECT causes the function definition
 662    to use __GI_* name and we need to add alias to the real name.
 663    There is no reason to use hidden_weak over hidden_def in assembly,
 664    but we provide it for consistency with the C usage.
 665    hidden_proto doesn't make sense for assembly but the equivalent
 666    is to call via the HIDDEN_JUMPTARGET macro instead of JUMPTARGET.  */
 667 #  define hidden_def(name)      strong_alias (name, __GI_##name)
 668 #  define hidden_weak(name)     hidden_def (name)
 669 #  define hidden_ver(local, name) strong_alias (local, __GI_##name)
 670 #  define hidden_data_def(name) strong_data_alias (name, __GI_##name)
 671 #  define hidden_data_weak(name)        hidden_data_def (name)
 672 #  define hidden_data_ver(local, name) strong_data_alias (local, __GI_##name)
 673 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 674 #   define HIDDEN_JUMPTARGET(name) .__GI_##name
 675 #  else
 676 #   define HIDDEN_JUMPTARGET(name) __GI_##name
 677 #  endif
 678 # endif
 679 #else
 680 # ifndef __ASSEMBLER__
 681 #  define hidden_proto(name, attrs...)
 682 # else
 683 #  define HIDDEN_JUMPTARGET(name) JUMPTARGET(name)
 684 # endif /* Not  __ASSEMBLER__ */
 685 # define hidden_weak(name)
 686 # define hidden_def(name)
 687 # define hidden_ver(local, name)
 688 # define hidden_data_weak(name)
 689 # define hidden_data_def(name)
 690 # define hidden_data_ver(local, name)
 691 #endif
 692
 693 #if !defined NOT_IN_libc
 694 # define libc_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 695 # define libc_hidden_def(name) hidden_def (name)
 696 # define libc_hidden_weak(name) hidden_weak (name)
 697 # define libc_hidden_ver(local, name) hidden_ver (local, name)
 698 # define libc_hidden_data_def(name) hidden_data_def (name)
 699 # define libc_hidden_data_weak(name) hidden_data_weak (name)
 700 # define libc_hidden_data_ver(local, name) hidden_data_ver (local, name)
 701 #else
 702 # define libc_hidden_proto(name, attrs...)
 703 # define libc_hidden_def(name)
 704 # define libc_hidden_weak(name)
 705 # define libc_hidden_ver(local, name)
 706 # define libc_hidden_data_def(name)
 707 # define libc_hidden_data_weak(name)
 708 # define libc_hidden_data_ver(local, name)
 709 #endif
 710
 711 #if defined NOT_IN_libc && defined IS_IN_rtld
 712 # define rtld_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 713 # define rtld_hidden_def(name) hidden_def (name)
 714 # define rtld_hidden_weak(name) hidden_weak (name)
 715 # define rtld_hidden_ver(local, name) hidden_ver (local, name)
 716 # define rtld_hidden_data_def(name) hidden_data_def (name)
 717 # define rtld_hidden_data_weak(name) hidden_data_weak (name)
 718 # define rtld_hidden_data_ver(local, name) hidden_data_ver (local, name)
 719 #else
 720 # define rtld_hidden_proto(name, attrs...)
 721 # define rtld_hidden_def(name)
 722 # define rtld_hidden_weak(name)
 723 # define rtld_hidden_ver(local, name)
 724 # define rtld_hidden_data_def(name)
 725 # define rtld_hidden_data_weak(name)
 726 # define rtld_hidden_data_ver(local, name)
 727 #endif
 728
 729 #if defined NOT_IN_libc && defined IS_IN_libm
 730 # define libm_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 731 # define libm_hidden_def(name) hidden_def (name)
 732 # define libm_hidden_weak(name) hidden_weak (name)
 733 # define libm_hidden_ver(local, name) hidden_ver (local, name)
 734 # define libm_hidden_data_def(name) hidden_data_def (name)
 735 # define libm_hidden_data_weak(name) hidden_data_weak (name)
 736 # define libm_hidden_data_ver(local, name) hidden_data_ver (local, name)
 737 #else
 738 # define libm_hidden_proto(name, attrs...)
 739 # define libm_hidden_def(name)
 740 # define libm_hidden_weak(name)
 741 # define libm_hidden_ver(local, name)
 742 # define libm_hidden_data_def(name)
 743 # define libm_hidden_data_weak(name)
 744 # define libm_hidden_data_ver(local, name)
 745 #endif
 746
 747 #if defined NOT_IN_libc && defined IS_IN_libresolv
 748 # define libresolv_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 749 # define libresolv_hidden_def(name) hidden_def (name)
 750 # define libresolv_hidden_weak(name) hidden_weak (name)
 751 # define libresolv_hidden_ver(local, name) hidden_ver (local, name)
 752 # define libresolv_hidden_data_def(name) hidden_data_def (name)
 753 # define libresolv_hidden_data_weak(name) hidden_data_weak (name)
 754 # define libresolv_hidden_data_ver(local, name) hidden_data_ver (local, name)
 755 #else
 756 # define libresolv_hidden_proto(name, attrs...)
 757 # define libresolv_hidden_def(name)
 758 # define libresolv_hidden_weak(name)
 759 # define libresolv_hidden_ver(local, name)
 760 # define libresolv_hidden_data_def(name)
 761 # define libresolv_hidden_data_weak(name)
 762 # define libresolv_hidden_data_ver(local, name)
 763 #endif
 764
 765 #ifdef HAVE_BUILTIN_REDIRECTION
 766 # define libc_hidden_builtin_proto(name, attrs...) libc_hidden_proto (name, ##attrs)
 767 # define libc_hidden_builtin_def(name) libc_hidden_def (name)
 768 # define libc_hidden_builtin_weak(name) libc_hidden_weak (name)
 769 # define libc_hidden_builtin_ver(local, name) libc_hidden_ver (local, name)
 770 # ifdef __ASSEMBLER__
 771 #  define HIDDEN_BUILTIN_JUMPTARGET(name) HIDDEN_JUMPTARGET(name)
 772 # endif
 773 #else
 774 # define libc_hidden_builtin_proto(name, attrs...)
 775 # define libc_hidden_builtin_def(name)
 776 # define libc_hidden_builtin_weak(name)
 777 # define libc_hidden_builtin_ver(local, name)
 778 # ifdef __ASSEMBLER__
 779 #  define HIDDEN_BUILTIN_JUMPTARGET(name) JUMPTARGET(name)
 780 # endif
 781 #endif
 782
 783 /* Get some dirty hacks.  */
 784 #include <symbol-hacks.h>
 785
 786 /* Move compatibility symbols out of the way by placing them all in a
 787    special section.  */
 788 #ifndef __ASSEMBLER__
 789 # define attribute_compat_text_section \
 790     __attribute__ ((section (".text.compat")))
 791 # define attribute_compat_data_section \
 792     __attribute__ ((section (".data.compat")))
 793 #else
 794 # define compat_text_section .section ".text.compat", "ax";
 795 # define compat_data_section .section ".data.compat", "aw";
 796 #endif
 797
 798 #endif /* libc-symbols.h */