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) 1995-1998,2000-2006,2008,2009 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_ELF if using ELF, which supports weak symbols using `.weak'.
  35    * HAVE_ASM_WEAK_DIRECTIVE if we have weak symbols using `.weak'.
  36    * HAVE_ASM_WEAKEXT_DIRECTIVE if we have weak symbols using `.weakext'.
  37
  38    */
  39
  40 /* This is defined for the compilation of all C library code.  features.h
  41    tests this to avoid inclusion of stubs.h while compiling the library,
  42    before stubs.h has been generated.  Some library code that is shared
  43    with other packages also tests this symbol to see if it is being
  44    compiled as part of the C library.  We must define this before including
  45    config.h, because it makes some definitions conditional on whether libc
  46    itself is being compiled, or just some generator program.  */
  47 #define _LIBC   1
  48
  49 /* Enable declarations of GNU extensions, since we are compiling them.  */
  50 #define _GNU_SOURCE     1
  51 /* And we also need the data for the reentrant functions.  */
  52 #define _REENTRANT      1
  53
  54 #include <config.h>
  55
  56 /* The symbols in all the user (non-_) macros are C symbols.
  57    NO HAVE_ELF implies a.out.  */
  58
  59 #if defined HAVE_ASM_WEAK_DIRECTIVE || defined HAVE_ASM_WEAKEXT_DIRECTIVE
  60 # define HAVE_WEAK_SYMBOLS
  61 #endif
  62
  63 #ifndef __SYMBOL_PREFIX
  64 # ifdef NO_UNDERSCORES
  65 #  define __SYMBOL_PREFIX
  66 # else
  67 #  define __SYMBOL_PREFIX "_"
  68 # endif
  69 #endif
  70
  71 #ifndef C_SYMBOL_NAME
  72 # ifdef NO_UNDERSCORES
  73 #  define C_SYMBOL_NAME(name) name
  74 # else
  75 #  define C_SYMBOL_NAME(name) _##name
  76 # endif
  77 #endif
  78
  79 #ifndef ASM_LINE_SEP
  80 # define ASM_LINE_SEP ;
  81 #endif
  82
  83 #ifdef HAVE_ASM_GLOBAL_DOT_NAME
  84 # ifndef C_SYMBOL_DOT_NAME
  85 #  if defined __GNUC__ && defined __GNUC_MINOR__ \
  86       && (__GNUC__ << 16) + __GNUC_MINOR__ >= (3 << 16) + 1
  87 #   define C_SYMBOL_DOT_NAME(name) .name
  88 #  else
  89 #   define C_SYMBOL_DOT_NAME(name) .##name
  90 #  endif
  91 # endif
  92 #endif
  93
  94 #ifndef __ASSEMBLER__
  95 /* GCC understands weak symbols and aliases; use its interface where
  96    possible, instead of embedded assembly language.  */
  97
  98 /* Define ALIASNAME as a strong alias for NAME.  */
  99 # define strong_alias(name, aliasname) _strong_alias(name, aliasname)
 100 # define _strong_alias(name, aliasname) \
 101   extern __typeof (name) aliasname __attribute__ ((alias (#name)));
 102
 103 /* This comes between the return type and function name in
 104    a function definition to make that definition weak.  */
 105 # define weak_function __attribute__ ((weak))
 106 # define weak_const_function __attribute__ ((weak, __const__))
 107
 108 # ifdef HAVE_WEAK_SYMBOLS
 109
 110 /* Define ALIASNAME as a weak alias for NAME.
 111    If weak aliases are not available, this defines a strong alias.  */
 112 #  define weak_alias(name, aliasname) _weak_alias (name, aliasname)
 113 #  define _weak_alias(name, aliasname) \
 114   extern __typeof (name) aliasname __attribute__ ((weak, alias (#name)));
 115
 116 /* Same as WEAK_ALIAS, but mark symbol as hidden.  */
 117 #  define weak_hidden_alias(name, aliasname) \
 118   _weak_hidden_alias (name, aliasname)
 119 #  define _weak_hidden_alias(name, aliasname) \
 120   extern __typeof (name) aliasname \
 121     __attribute__ ((weak, alias (#name), __visibility__ ("hidden")));
 122
 123 /* Declare SYMBOL as weak undefined symbol (resolved to 0 if not defined).  */
 124 #  define weak_extern(symbol) _weak_extern (weak symbol)
 125 #  define _weak_extern(expr) _Pragma (#expr)
 126
 127 # else
 128
 129 #  define weak_alias(name, aliasname) strong_alias(name, aliasname)
 130 #  define weak_hidden_alias(name, aliasname) strong_alias(name, aliasname)
 131 #  define weak_extern(symbol) /* Nothing. */
 132
 133 # endif
 134
 135 #else /* __ASSEMBLER__ */
 136
 137 # ifdef HAVE_ASM_SET_DIRECTIVE
 138 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 139 #   define strong_alias(original, alias)                                \
 140   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 141   .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original) ASM_LINE_SEP      \
 142   ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP           \
 143   .set C_SYMBOL_DOT_NAME (alias),C_SYMBOL_DOT_NAME (original)
 144 #   define strong_data_alias(original, alias)                           \
 145   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 146   .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original)
 147 #  else
 148 #   define strong_alias(original, alias)                                \
 149   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 150   .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original)
 151 #   define strong_data_alias(original, alias) strong_alias(original, alias)
 152 #  endif
 153 # else
 154 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 155 #   define strong_alias(original, alias)                                \
 156   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 157   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original) ASM_LINE_SEP         \
 158   ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP           \
 159   C_SYMBOL_DOT_NAME (alias) = C_SYMBOL_DOT_NAME (original)
 160 #   define strong_data_alias(original, alias)                           \
 161   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 162   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
 163 #  else
 164 #   define strong_alias(original, alias)                                \
 165   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 166   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
 167 #   define strong_data_alias(original, alias) strong_alias(original, alias)
 168 #  endif
 169 # endif
 170
 171 # ifdef HAVE_WEAK_SYMBOLS
 172 #  ifdef HAVE_ASM_WEAKEXT_DIRECTIVE
 173 #   ifdef HAVE_ASM_GLOBAL_DOT_NAME
 174 #    define weak_alias(original, alias)                                 \
 175   .weakext C_SYMBOL_NAME (alias), C_SYMBOL_NAME (original) ASM_LINE_SEP \
 176   .weakext C_SYMBOL_DOT_NAME (alias), C_SYMBOL_DOT_NAME (original)
 177 #   else
 178 #    define weak_alias(original, alias)                                 \
 179   .weakext C_SYMBOL_NAME (alias), C_SYMBOL_NAME (original)
 180 #   endif
 181 #   define weak_extern(symbol)                                          \
 182   .weakext C_SYMBOL_NAME (symbol)
 183
 184 #  else /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
 185
 186 #   ifdef HAVE_ASM_GLOBAL_DOT_NAME
 187 #    define weak_alias(original, alias)                                 \
 188   .weak C_SYMBOL_NAME (alias) ASM_LINE_SEP                              \
 189   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original) ASM_LINE_SEP         \
 190   .weak C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP                          \
 191   C_SYMBOL_DOT_NAME (alias) = C_SYMBOL_DOT_NAME (original)
 192 #   else
 193 #    define weak_alias(original, alias)                                 \
 194   .weak C_SYMBOL_NAME (alias) ASM_LINE_SEP                              \
 195   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
 196 #   endif
 197
 198 #   define weak_extern(symbol)                                          \
 199   .weak C_SYMBOL_NAME (symbol)
 200
 201 #  endif /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
 202
 203 # else /* ! HAVE_WEAK_SYMBOLS */
 204
 205 #  define weak_alias(original, alias) strong_alias(original, alias)
 206 #  define weak_extern(symbol) /* Nothing */
 207 # endif /* ! HAVE_WEAK_SYMBOLS */
 208
 209 #endif /* __ASSEMBLER__ */
 210
 211 /* On some platforms we can make internal function calls (i.e., calls of
 212    functions not exported) a bit faster by using a different calling
 213    convention.  */
 214 #ifndef internal_function
 215 # define internal_function      /* empty */
 216 #endif
 217
 218 /* Prepare for the case that `__builtin_expect' is not available.  */
 219 #ifndef HAVE_BUILTIN_EXPECT
 220 # define __builtin_expect(expr, val) (expr)
 221 #endif
 222
 223 /* Determine the return address.  */
 224 #define RETURN_ADDRESS(nr) \
 225   __builtin_extract_return_addr (__builtin_return_address (nr))
 226
 227 /* When a reference to SYMBOL is encountered, the linker will emit a
 228    warning message MSG.  */
 229 #ifdef HAVE_ELF
 230
 231 /* We want the .gnu.warning.SYMBOL section to be unallocated.  */
 232 # ifdef HAVE_ASM_PREVIOUS_DIRECTIVE
 233 #  define __make_section_unallocated(section_string)    \
 234   asm (".section " section_string "\n\t.previous");
 235 # elif defined HAVE_ASM_POPSECTION_DIRECTIVE
 236 #  define __make_section_unallocated(section_string)    \
 237   asm (".pushsection " section_string "\n\t.popsection");
 238 # else
 239 #  define __make_section_unallocated(section_string)
 240 # endif
 241
 242 /* Tacking on "\n\t#" to the section name makes gcc put it's bogus
 243    section attributes on what looks like a comment to the assembler.  */
 244 # ifdef HAVE_SECTION_QUOTES
 245 #  define __sec_comment "\"\n\t#\""
 246 # else
 247 #  define __sec_comment "\n\t#"
 248 # endif
 249 # define link_warning(symbol, msg) \
 250   __make_section_unallocated (".gnu.warning." #symbol) \
 251   static const char __evoke_link_warning_##symbol[]     \
 252     __attribute__ ((used, section (".gnu.warning." #symbol __sec_comment))) \
 253     = msg;
 254 # define libc_freeres_ptr(decl) \
 255   __make_section_unallocated ("__libc_freeres_ptrs, \"aw\", %nobits") \
 256   decl __attribute__ ((section ("__libc_freeres_ptrs" __sec_comment)))
 257 # define __libc_freeres_fn_section \
 258   __attribute__ ((section ("__libc_freeres_fn")))
 259 #else /* Not ELF: a.out */
 260 # ifdef HAVE_XCOFF
 261 /* XCOFF does not support .stabs.
 262    The native aix linker will remove the .stab and .stabstr sections
 263    The gnu linker will have a fatal error if there is a relocation for
 264    symbol in the .stab section.  Silently disable this macro.  */
 265 #  define link_warning(symbol, msg)
 266 # else
 267 #  define link_warning(symbol, msg)             \
 268      asm (".stabs \"" msg "\",30,0,0,0\n\t"     \
 269           ".stabs \"" __SYMBOL_PREFIX #symbol "\",1,0,0,0\n");
 270 # endif /* XCOFF */
 271 # define libc_freeres_ptr(decl) decl
 272 # define __libc_freeres_fn_section
 273 #endif
 274 #define libc_freeres_fn(name)   \
 275   static void name (void) __attribute_used__ __libc_freeres_fn_section; \
 276   text_set_element (__libc_subfreeres, name);                           \
 277   static void name (void)
 278
 279 /* A canned warning for sysdeps/stub functions.  */
 280 #define stub_warning(name) \
 281   __make_section_unallocated (".gnu.glibc-stub." #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') of SIZE bytes
 297    alias to ORIGINAL, when the assembler supports such declarations
 298    (such as in ELF).
 299    This is only necessary when defining something in assembly, or playing
 300    funny alias games where the size should be other than what the compiler
 301    thinks it is.  */
 302 #define declare_symbol_alias(symbol, original, type, size) \
 303   declare_symbol_alias_1 (symbol, original, type, size)
 304 #ifdef ASM_TYPE_DIRECTIVE_PREFIX
 305 # ifdef __ASSEMBLER__
 306 #  define declare_symbol_alias_1(symbol, original, type, size) \
 307     strong_alias (original, symbol); \
 308     .type C_SYMBOL_NAME (symbol), \
 309           declare_symbol_alias_1_paste (ASM_TYPE_DIRECTIVE_PREFIX, type); \
 310     .size C_SYMBOL_NAME (symbol), size
 311 #  define declare_symbol_alias_1_paste(a, b) \
 312   declare_symbol_alias_1_paste_1 (a,b)
 313 #  define declare_symbol_alias_1_paste_1(a,b)   a##b
 314 # else /* Not __ASSEMBLER__.  */
 315 #  define declare_symbol_alias_1(symbol, original, type, size) \
 316     asm (declare_symbol_alias_1_stringify (ASM_GLOBAL_DIRECTIVE) \
 317          " " __SYMBOL_PREFIX #symbol \
 318          "\n\t" declare_symbol_alias_1_alias (symbol, original) \
 319          "\n\t.type " __SYMBOL_PREFIX #symbol ", " \
 320          declare_symbol_alias_1_stringify (ASM_TYPE_DIRECTIVE_PREFIX) #type \
 321          "\n\t.size " __SYMBOL_PREFIX #symbol ", " #size);
 322 #  define declare_symbol_alias_1_stringify(x) \
 323   declare_symbol_alias_1_stringify_1 (x)
 324 #  define declare_symbol_alias_1_stringify_1(x) #x
 325 #  ifdef HAVE_ASM_SET_DIRECTIVE
 326 #   define declare_symbol_alias_1_alias(symbol, original) \
 327          ".set " __SYMBOL_PREFIX #symbol ", " __SYMBOL_PREFIX #original
 328 #  else
 329 #   define declare_symbol_alias_1_alias(symbol, original) \
 330          __SYMBOL_PREFIX #symbol " = " __SYMBOL_PREFIX #original
 331 #  endif /* HAVE_ASM_SET_DIRECTIVE */
 332 # endif /* __ASSEMBLER__ */
 333 #else
 334 # define declare_symbol_1(symbol, type, size) /* Nothing.  */
 335 #endif
 336
 337
 338 /*
 339 \f
 340 */
 341
 342 /* Symbol set support macros.  */
 343
 344 #ifdef HAVE_ELF
 345
 346 /* Make SYMBOL, which is in the text segment, an element of SET.  */
 347 # define text_set_element(set, symbol)  _elf_set_element(set, symbol)
 348 /* Make SYMBOL, which is in the data segment, an element of SET.  */
 349 # define data_set_element(set, symbol)  _elf_set_element(set, symbol)
 350 /* Make SYMBOL, which is in the bss segment, an element of SET.  */
 351 # define bss_set_element(set, symbol)   _elf_set_element(set, symbol)
 352
 353 /* These are all done the same way in ELF.
 354    There is a new section created for each set.  */
 355 # ifdef SHARED
 356 /* When building a shared library, make the set section writable,
 357    because it will need to be relocated at run time anyway.  */
 358 #  define _elf_set_element(set, symbol) \
 359   static const void *__elf_set_##set##_element_##symbol##__ \
 360     __attribute__ ((used, section (#set))) = &(symbol)
 361 # else
 362 #  define _elf_set_element(set, symbol) \
 363   static const void *const __elf_set_##set##_element_##symbol##__ \
 364     __attribute__ ((used, section (#set))) = &(symbol)
 365 # endif
 366
 367 /* Define SET as a symbol set.  This may be required (it is in a.out) to
 368    be able to use the set's contents.  */
 369 # define symbol_set_define(set) symbol_set_declare(set)
 370
 371 /* Declare SET for use in this module, if defined in another module.
 372    In a shared library, this is always local to that shared object.
 373    For static linking, the set might be wholly absent and so we use
 374    weak references.  */
 375 # define symbol_set_declare(set) \
 376   extern char const __start_##set[] __symbol_set_attribute; \
 377   extern char const __stop_##set[] __symbol_set_attribute;
 378 # ifdef SHARED
 379 #  define __symbol_set_attribute attribute_hidden
 380 # else
 381 #  define __symbol_set_attribute __attribute__ ((weak))
 382 # endif
 383
 384 /* Return a pointer (void *const *) to the first element of SET.  */
 385 # define symbol_set_first_element(set)  ((void *const *) (&__start_##set))
 386
 387 /* Return true iff PTR (a void *const *) has been incremented
 388    past the last element in SET.  */
 389 # define symbol_set_end_p(set, ptr) ((ptr) >= (void *const *) &__stop_##set)
 390
 391 #else   /* Not ELF: a.out.  */
 392
 393 # ifdef HAVE_XCOFF
 394 /* XCOFF does not support .stabs.
 395    The native aix linker will remove the .stab and .stabstr sections
 396    The gnu linker will have a fatal error if there is a relocation for
 397    symbol in the .stab section.  Silently disable these macros.  */
 398 #  define text_set_element(set, symbol)
 399 #  define data_set_element(set, symbol)
 400 #  define bss_set_element(set, symbol)
 401 # else
 402 #  define text_set_element(set, symbol) \
 403     asm (".stabs \"" __SYMBOL_PREFIX #set "\",23,0,0," __SYMBOL_PREFIX #symbol)
 404 #  define data_set_element(set, symbol) \
 405     asm (".stabs \"" __SYMBOL_PREFIX #set "\",25,0,0," __SYMBOL_PREFIX #symbol)
 406 #  define bss_set_element(set, symbol)  ?error Must use initialized data.
 407 # endif /* XCOFF */
 408 # define symbol_set_define(set) void *const (set)[1];
 409 # define symbol_set_declare(set)        extern void *const (set)[1];
 410
 411 # define symbol_set_first_element(set)  &(set)[1]
 412 # define symbol_set_end_p(set, ptr)     (*(ptr) == 0)
 413
 414 #endif  /* ELF.  */
 415
 416 #if DO_VERSIONING
 417 # define symbol_version(real, name, version) \
 418      _symbol_version(real, name, version)
 419 # define default_symbol_version(real, name, version) \
 420      _default_symbol_version(real, name, version)
 421 # ifdef __ASSEMBLER__
 422 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 423 #   define _symbol_version(real, name, version) \
 424      .symver real, name##@##version ASM_LINE_SEP                        \
 425      .symver C_SYMBOL_DOT_NAME(real), C_SYMBOL_DOT_NAME(name##@##version)
 426 #   define _default_symbol_version(real, name, version) \
 427      .symver real, name##@##@##version ASM_LINE_SEP                     \
 428      .symver C_SYMBOL_DOT_NAME(real), C_SYMBOL_DOT_NAME(name##@##@##version)
 429 #  else
 430 #   define _symbol_version(real, name, version) \
 431      .symver real, name##@##version
 432 #   define _default_symbol_version(real, name, version) \
 433      .symver real, name##@##@##version
 434 #  endif
 435 # else
 436 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 437 #   define _symbol_version(real, name, version) \
 438      __asm__ (".symver " #real "," #name "@" #version "\n\t"    \
 439               ".symver ." #real ",." #name "@" #version)
 440 #   define _default_symbol_version(real, name, version) \
 441      __asm__ (".symver " #real "," #name "@@" #version "\n\t"   \
 442               ".symver ." #real ",." #name "@@" #version)
 443 #  else
 444 #   define _symbol_version(real, name, version) \
 445      __asm__ (".symver " #real "," #name "@" #version)
 446 #   define _default_symbol_version(real, name, version) \
 447      __asm__ (".symver " #real "," #name "@@" #version)
 448 #  endif
 449 # endif
 450 #else
 451 # define symbol_version(real, name, version)
 452 # define default_symbol_version(real, name, version) \
 453   strong_alias(real, name)
 454 #endif
 455
 456 #if defined SHARED || defined LIBC_NONSHARED
 457 # define attribute_hidden __attribute__ ((visibility ("hidden")))
 458 #else
 459 # define attribute_hidden
 460 #endif
 461
 462 #ifdef HAVE_TLS_MODEL_ATTRIBUTE
 463 # define attribute_tls_model_ie __attribute__ ((tls_model ("initial-exec")))
 464 #else
 465 # define attribute_tls_model_ie
 466 #endif
 467
 468 #define attribute_relro __attribute__ ((section (".data.rel.ro")))
 469
 470 /* Handling on non-exported internal names.  We have to do this only
 471    for shared code.  */
 472 #ifdef SHARED
 473 # define INTUSE(name) name##_internal
 474 # define INTDEF(name) strong_alias (name, name##_internal)
 475 # define INTVARDEF(name) \
 476   _INTVARDEF (name, name##_internal)
 477 # define _INTVARDEF(name, aliasname) \
 478   extern __typeof (name) aliasname __attribute__ ((alias (#name), \
 479                                                    visibility ("hidden")));
 480 # define INTDEF2(name, newname) strong_alias (name, newname##_internal)
 481 # define INTVARDEF2(name, newname) _INTVARDEF (name, newname##_internal)
 482 #else
 483 # define INTUSE(name) name
 484 # define INTDEF(name)
 485 # define INTVARDEF(name)
 486 # define INTDEF2(name, newname)
 487 # define INTVARDEF2(name, newname)
 488 #endif
 489
 490 /* The following macros are used for PLT bypassing within libc.so
 491    (and if needed other libraries similarly).
 492    First of all, you need to have the function prototyped somewhere,
 493    say in foo/foo.h:
 494
 495    int foo (int __bar);
 496
 497    If calls to foo within libc.so should always go to foo defined in libc.so,
 498    then in include/foo.h you add:
 499
 500    libc_hidden_proto (foo)
 501
 502    line and after the foo function definition:
 503
 504    int foo (int __bar)
 505    {
 506      return __bar;
 507    }
 508    libc_hidden_def (foo)
 509
 510    or
 511
 512    int foo (int __bar)
 513    {
 514      return __bar;
 515    }
 516    libc_hidden_weak (foo)
 517
 518    Similarly for global data.  If references to foo within libc.so should
 519    always go to foo defined in libc.so, then in include/foo.h you add:
 520
 521    libc_hidden_proto (foo)
 522
 523    line and after foo's definition:
 524
 525    int foo = INITIAL_FOO_VALUE;
 526    libc_hidden_data_def (foo)
 527
 528    or
 529
 530    int foo = INITIAL_FOO_VALUE;
 531    libc_hidden_data_weak (foo)
 532
 533    If foo is normally just an alias (strong or weak) to some other function,
 534    you should use the normal strong_alias first, then add libc_hidden_def
 535    or libc_hidden_weak:
 536
 537    int baz (int __bar)
 538    {
 539      return __bar;
 540    }
 541    strong_alias (baz, foo)
 542    libc_hidden_weak (foo)
 543
 544    If the function should be internal to multiple objects, say ld.so and
 545    libc.so, the best way is to use:
 546
 547    #if !defined NOT_IN_libc || defined IS_IN_rtld
 548    hidden_proto (foo)
 549    #endif
 550
 551    in include/foo.h and the normal macros at all function definitions
 552    depending on what DSO they belong to.
 553
 554    If versioned_symbol macro is used to define foo,
 555    libc_hidden_ver macro should be used, as in:
 556
 557    int __real_foo (int __bar)
 558    {
 559      return __bar;
 560    }
 561    versioned_symbol (libc, __real_foo, foo, GLIBC_2_1);
 562    libc_hidden_ver (__real_foo, foo)  */
 563
 564 #if defined SHARED && defined DO_VERSIONING && !defined NO_HIDDEN
 565 # ifndef __ASSEMBLER__
 566 #  define __hidden_proto_hiddenattr(attrs...) \
 567   __attribute__ ((visibility ("hidden"), ##attrs))
 568 #  define hidden_proto(name, attrs...) \
 569   __hidden_proto (name, __GI_##name, ##attrs)
 570 #  define __hidden_proto(name, internal, attrs...) \
 571   extern __typeof (name) name __asm__ (__hidden_asmname (#internal)) \
 572   __hidden_proto_hiddenattr (attrs);
 573 #  define __hidden_asmname(name) \
 574   __hidden_asmname1 (__USER_LABEL_PREFIX__, name)
 575 #  define __hidden_asmname1(prefix, name) __hidden_asmname2(prefix, name)
 576 #  define __hidden_asmname2(prefix, name) #prefix name
 577 #  define __hidden_ver1(local, internal, name) \
 578   extern __typeof (name) __EI_##name __asm__(__hidden_asmname (#internal)); \
 579   extern __typeof (name) __EI_##name \
 580         __attribute__((alias (__hidden_asmname (#local))))
 581 #  define hidden_ver(local, name)       __hidden_ver1(local, __GI_##name, name);
 582 #  define hidden_data_ver(local, name)  hidden_ver(local, name)
 583 #  define hidden_def(name)              __hidden_ver1(__GI_##name, name, name);
 584 #  define hidden_data_def(name)         hidden_def(name)
 585 #  define hidden_weak(name) \
 586         __hidden_ver1(__GI_##name, name, name) __attribute__((weak));
 587 #  define hidden_data_weak(name)        hidden_weak(name)
 588 # else
 589 /* For assembly, we need to do the opposite of what we do in C:
 590    in assembly gcc __REDIRECT stuff is not in place, so functions
 591    are defined by its normal name and we need to create the
 592    __GI_* alias to it, in C __REDIRECT causes the function definition
 593    to use __GI_* name and we need to add alias to the real name.
 594    There is no reason to use hidden_weak over hidden_def in assembly,
 595    but we provide it for consistency with the C usage.
 596    hidden_proto doesn't make sense for assembly but the equivalent
 597    is to call via the HIDDEN_JUMPTARGET macro instead of JUMPTARGET.  */
 598 #  define hidden_def(name)      strong_alias (name, __GI_##name)
 599 #  define hidden_weak(name)     hidden_def (name)
 600 #  define hidden_ver(local, name) strong_alias (local, __GI_##name)
 601 #  define hidden_data_def(name) strong_data_alias (name, __GI_##name)
 602 #  define hidden_data_weak(name)        hidden_data_def (name)
 603 #  define hidden_data_ver(local, name) strong_data_alias (local, __GI_##name)
 604 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 605 #   define HIDDEN_JUMPTARGET(name) .__GI_##name
 606 #  else
 607 #   define HIDDEN_JUMPTARGET(name) __GI_##name
 608 #  endif
 609 # endif
 610 #else
 611 # ifndef __ASSEMBLER__
 612 #  define hidden_proto(name, attrs...)
 613 # else
 614 #  define HIDDEN_JUMPTARGET(name) JUMPTARGET(name)
 615 # endif /* Not  __ASSEMBLER__ */
 616 # define hidden_weak(name)
 617 # define hidden_def(name)
 618 # define hidden_ver(local, name)
 619 # define hidden_data_weak(name)
 620 # define hidden_data_def(name)
 621 # define hidden_data_ver(local, name)
 622 #endif
 623
 624 #if !defined NOT_IN_libc
 625 # define libc_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 626 # define libc_hidden_def(name) hidden_def (name)
 627 # define libc_hidden_weak(name) hidden_weak (name)
 628 # define libc_hidden_ver(local, name) hidden_ver (local, name)
 629 # define libc_hidden_data_def(name) hidden_data_def (name)
 630 # define libc_hidden_data_weak(name) hidden_data_weak (name)
 631 # define libc_hidden_data_ver(local, name) hidden_data_ver (local, name)
 632 #else
 633 # define libc_hidden_proto(name, attrs...)
 634 # define libc_hidden_def(name)
 635 # define libc_hidden_weak(name)
 636 # define libc_hidden_ver(local, name)
 637 # define libc_hidden_data_def(name)
 638 # define libc_hidden_data_weak(name)
 639 # define libc_hidden_data_ver(local, name)
 640 #endif
 641
 642 #if defined NOT_IN_libc && defined IS_IN_rtld
 643 # define rtld_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 644 # define rtld_hidden_def(name) hidden_def (name)
 645 # define rtld_hidden_weak(name) hidden_weak (name)
 646 # define rtld_hidden_ver(local, name) hidden_ver (local, name)
 647 # define rtld_hidden_data_def(name) hidden_data_def (name)
 648 # define rtld_hidden_data_weak(name) hidden_data_weak (name)
 649 # define rtld_hidden_data_ver(local, name) hidden_data_ver (local, name)
 650 #else
 651 # define rtld_hidden_proto(name, attrs...)
 652 # define rtld_hidden_def(name)
 653 # define rtld_hidden_weak(name)
 654 # define rtld_hidden_ver(local, name)
 655 # define rtld_hidden_data_def(name)
 656 # define rtld_hidden_data_weak(name)
 657 # define rtld_hidden_data_ver(local, name)
 658 #endif
 659
 660 #if defined NOT_IN_libc && defined IS_IN_libm
 661 # define libm_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 662 # define libm_hidden_def(name) hidden_def (name)
 663 # define libm_hidden_weak(name) hidden_weak (name)
 664 # define libm_hidden_ver(local, name) hidden_ver (local, name)
 665 # define libm_hidden_data_def(name) hidden_data_def (name)
 666 # define libm_hidden_data_weak(name) hidden_data_weak (name)
 667 # define libm_hidden_data_ver(local, name) hidden_data_ver (local, name)
 668 #else
 669 # define libm_hidden_proto(name, attrs...)
 670 # define libm_hidden_def(name)
 671 # define libm_hidden_weak(name)
 672 # define libm_hidden_ver(local, name)
 673 # define libm_hidden_data_def(name)
 674 # define libm_hidden_data_weak(name)
 675 # define libm_hidden_data_ver(local, name)
 676 #endif
 677
 678 #if defined NOT_IN_libc && defined IS_IN_libresolv
 679 # define libresolv_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 680 # define libresolv_hidden_def(name) hidden_def (name)
 681 # define libresolv_hidden_weak(name) hidden_weak (name)
 682 # define libresolv_hidden_ver(local, name) hidden_ver (local, name)
 683 # define libresolv_hidden_data_def(name) hidden_data_def (name)
 684 # define libresolv_hidden_data_weak(name) hidden_data_weak (name)
 685 # define libresolv_hidden_data_ver(local, name) hidden_data_ver (local, name)
 686 #else
 687 # define libresolv_hidden_proto(name, attrs...)
 688 # define libresolv_hidden_def(name)
 689 # define libresolv_hidden_weak(name)
 690 # define libresolv_hidden_ver(local, name)
 691 # define libresolv_hidden_data_def(name)
 692 # define libresolv_hidden_data_weak(name)
 693 # define libresolv_hidden_data_ver(local, name)
 694 #endif
 695
 696 #if defined NOT_IN_libc && defined IS_IN_librt
 697 # define librt_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 698 # define librt_hidden_def(name) hidden_def (name)
 699 # define librt_hidden_weak(name) hidden_weak (name)
 700 # define librt_hidden_ver(local, name) hidden_ver (local, name)
 701 # define librt_hidden_data_def(name) hidden_data_def (name)
 702 # define librt_hidden_data_weak(name) hidden_data_weak (name)
 703 # define librt_hidden_data_ver(local, name) hidden_data_ver (local, name)
 704 #else
 705 # define librt_hidden_proto(name, attrs...)
 706 # define librt_hidden_def(name)
 707 # define librt_hidden_weak(name)
 708 # define librt_hidden_ver(local, name)
 709 # define librt_hidden_data_def(name)
 710 # define librt_hidden_data_weak(name)
 711 # define librt_hidden_data_ver(local, name)
 712 #endif
 713
 714 #if defined NOT_IN_libc && defined IS_IN_libdl
 715 # define libdl_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 716 # define libdl_hidden_def(name) hidden_def (name)
 717 # define libdl_hidden_weak(name) hidden_weak (name)
 718 # define libdl_hidden_ver(local, name) hidden_ver (local, name)
 719 # define libdl_hidden_data_def(name) hidden_data_def (name)
 720 # define libdl_hidden_data_weak(name) hidden_data_weak (name)
 721 # define libdl_hidden_data_ver(local, name) hidden_data_ver (local, name)
 722 #else
 723 # define libdl_hidden_proto(name, attrs...)
 724 # define libdl_hidden_def(name)
 725 # define libdl_hidden_weak(name)
 726 # define libdl_hidden_ver(local, name)
 727 # define libdl_hidden_data_def(name)
 728 # define libdl_hidden_data_weak(name)
 729 # define libdl_hidden_data_ver(local, name)
 730 #endif
 731
 732 #if defined NOT_IN_libc && defined IS_IN_libnss_files
 733 # define libnss_files_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 734 # define libnss_files_hidden_def(name) hidden_def (name)
 735 # define libnss_files_hidden_weak(name) hidden_weak (name)
 736 # define libnss_files_hidden_ver(local, name) hidden_ver (local, name)
 737 # define libnss_files_hidden_data_def(name) hidden_data_def (name)
 738 # define libnss_files_hidden_data_weak(name) hidden_data_weak (name)
 739 # define libnss_files_hidden_data_ver(local, name) hidden_data_ver(local, name)
 740 #else
 741 # define libnss_files_hidden_proto(name, attrs...)
 742 # define libnss_files_hidden_def(name)
 743 # define libnss_files_hidden_weak(name)
 744 # define libnss_files_hidden_ver(local, name)
 745 # define libnss_files_hidden_data_def(name)
 746 # define libnss_files_hidden_data_weak(name)
 747 # define libnss_files_hidden_data_ver(local, name)
 748 #endif
 749
 750 #if defined NOT_IN_libc && defined IS_IN_libnsl
 751 # define libnsl_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 752 # define libnsl_hidden_def(name) hidden_def (name)
 753 # define libnsl_hidden_weak(name) hidden_weak (name)
 754 # define libnsl_hidden_ver(local, name) hidden_ver (local, name)
 755 # define libnsl_hidden_data_def(name) hidden_data_def (name)
 756 # define libnsl_hidden_data_weak(name) hidden_data_weak (name)
 757 # define libnsl_hidden_data_ver(local, name) hidden_data_ver (local, name)
 758 #else
 759 # define libnsl_hidden_proto(name, attrs...)
 760 # define libnsl_hidden_def(name)
 761 # define libnsl_hidden_weak(name)
 762 # define libnsl_hidden_ver(local, name)
 763 # define libnsl_hidden_data_def(name)
 764 # define libnsl_hidden_data_weak(name)
 765 # define libnsl_hidden_data_ver(local, name)
 766 #endif
 767
 768 #if defined NOT_IN_libc && defined IS_IN_libnss_nisplus
 769 # define libnss_nisplus_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 770 # define libnss_nisplus_hidden_def(name) hidden_def (name)
 771 # define libnss_nisplus_hidden_weak(name) hidden_weak (name)
 772 # define libnss_nisplus_hidden_ver(local, name) hidden_ver (local, name)
 773 # define libnss_nisplus_hidden_data_def(name) hidden_data_def (name)
 774 # define libnss_nisplus_hidden_data_weak(name) hidden_data_weak (name)
 775 # define libnss_nisplus_hidden_data_ver(local, name) hidden_data_ver (local, name)
 776 #else
 777 # define libnss_nisplus_hidden_proto(name, attrs...)
 778 # define libnss_nisplus_hidden_def(name)
 779 # define libnss_nisplus_hidden_weak(name)
 780 # define libnss_nisplus_hidden_ver(local, name)
 781 # define libnss_nisplus_hidden_data_def(name)
 782 # define libnss_nisplus_hidden_data_weak(name)
 783 # define libnss_nisplus_hidden_data_ver(local, name)
 784 #endif
 785
 786 #ifdef HAVE_BUILTIN_REDIRECTION
 787 # define libc_hidden_builtin_proto(name, attrs...) libc_hidden_proto (name, ##attrs)
 788 # define libc_hidden_builtin_def(name) libc_hidden_def (name)
 789 # define libc_hidden_builtin_weak(name) libc_hidden_weak (name)
 790 # define libc_hidden_builtin_ver(local, name) libc_hidden_ver (local, name)
 791 # ifdef __ASSEMBLER__
 792 #  define HIDDEN_BUILTIN_JUMPTARGET(name) HIDDEN_JUMPTARGET(name)
 793 # endif
 794 #else
 795 # define libc_hidden_builtin_proto(name, attrs...)
 796 # define libc_hidden_builtin_def(name)
 797 # define libc_hidden_builtin_weak(name)
 798 # define libc_hidden_builtin_ver(local, name)
 799 # ifdef __ASSEMBLER__
 800 #  define HIDDEN_BUILTIN_JUMPTARGET(name) JUMPTARGET(name)
 801 # endif
 802 #endif
 803
 804 #if defined NOT_IN_libc && defined IS_IN_libutil
 805 # define libutil_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 806 # define libutil_hidden_def(name) hidden_def (name)
 807 # define libutil_hidden_weak(name) hidden_weak (name)
 808 # define libutil_hidden_ver(local, name) hidden_ver (local, name)
 809 # define libutil_hidden_data_def(name) hidden_data_def (name)
 810 # define libutil_hidden_data_weak(name) hidden_data_weak (name)
 811 # define libutil_hidden_data_ver(local, name) hidden_data_ver (local, name)
 812 #else
 813 # define libutil_hidden_proto(name, attrs...)
 814 # define libutil_hidden_def(name)
 815 # define libutil_hidden_weak(name)
 816 # define libutil_hidden_ver(local, name)
 817 # define libutil_hidden_data_def(name)
 818 # define libutil_hidden_data_weak(name)
 819 # define libutil_hidden_data_ver(local, name)
 820 #endif
 821
 822 /* Get some dirty hacks.  */
 823 #include <symbol-hacks.h>
 824
 825 /* Move compatibility symbols out of the way by placing them all in a
 826    special section.  */
 827 #ifndef __ASSEMBLER__
 828 # define attribute_compat_text_section \
 829     __attribute__ ((section (".text.compat")))
 830 # define attribute_compat_data_section \
 831     __attribute__ ((section (".data.compat")))
 832 #else
 833 # define compat_text_section .section ".text.compat", "ax";
 834 # define compat_data_section .section ".data.compat", "aw";
 835 #endif
 836
 837 /* Marker used for indirection function symbols.  */
 838 #define libc_ifunc(name, expr)                                          \
 839   extern void *name##_ifunc (void) __asm__ (#name);                     \
 840   void *name##_ifunc (void)                                             \
 841   {                                                                     \
 842     INIT_ARCH ();                                                       \
 843     __typeof (name) *res = expr;                                        \
 844     return res;                                                         \
 845   }                                                                     \
 846   __asm__ (".type " #name ", %gnu_indirect_function");
 847
 848 /* The body of the function is supposed to use __get_cpu_features
 849    which will, if necessary, initialize the data first.  */
 850 #define libm_ifunc(name, expr)                                          \
 851   extern void *name##_ifunc (void) __asm__ (#name);                     \
 852   void *name##_ifunc (void)                                             \
 853   {                                                                     \
 854     __typeof (name) *res = expr;                                        \
 855     return res;                                                         \
 856   }                                                                     \
 857   __asm__ (".type " #name ", %gnu_indirect_function");
 858
 859 #ifdef HAVE_ASM_SET_DIRECTIVE
 860 # define libc_ifunc_hidden_def1(local, name)                            \
 861     __asm__ (declare_symbol_alias_1_stringify (ASM_GLOBAL_DIRECTIVE)    \
 862              " " #local "\n\t"                                          \
 863              ".hidden " #local "\n\t"                                   \
 864              ".set " #local ", " #name);
 865 #else
 866 # define libc_ifunc_hidden_def1(local, name)                            \
 867     __asm__ (declare_symbol_alias_1_stringify (ASM_GLOBAL_DIRECTIVE)    \
 868              " " #local "\n\t"                                          \
 869              ".hidden " #local "\n\t"                                   \
 870              #local " = " #name);
 871 #endif
 872
 873 #define libc_ifunc_hidden_def(name) \
 874   libc_ifunc_hidden_def1 (__GI_##name, name)
 875
 876 #endif /* libc-symbols.h */