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) 1995-2014 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, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef _LIBC_SYMBOLS_H
  21 #define _LIBC_SYMBOLS_H 1
  22
  23 /* This file's macros are included implicitly in the compilation of every
  24    file in the C library by -imacros.
  25
  26    We include config.h which is generated by configure.
  27    It should define for us the following symbols:
  28
  29    * HAVE_ASM_SET_DIRECTIVE if we have `.set B, A' instead of `A = B'.
  30    * HAVE_ASM_WEAK_DIRECTIVE if we have weak symbols using `.weak'.
  31    * HAVE_ASM_WEAKEXT_DIRECTIVE if we have weak symbols using `.weakext'.
  32
  33    */
  34
  35 /* This is defined for the compilation of all C library code.  features.h
  36    tests this to avoid inclusion of stubs.h while compiling the library,
  37    before stubs.h has been generated.  Some library code that is shared
  38    with other packages also tests this symbol to see if it is being
  39    compiled as part of the C library.  We must define this before including
  40    config.h, because it makes some definitions conditional on whether libc
  41    itself is being compiled, or just some generator program.  */
  42 #define _LIBC   1
  43
  44 /* Enable declarations of GNU extensions, since we are compiling them.  */
  45 #define _GNU_SOURCE     1
  46 /* And we also need the data for the reentrant functions.  */
  47 #define _REENTRANT      1
  48
  49 #include <config.h>
  50
  51 /* Define this for the benefit of portable GNU code that wants to check it.
  52    Code that checks with #if will not #include <config.h> again, since we've
  53    already done it (and this file is implicitly included in every compile,
  54    via -include).  Code that checks with #ifdef will #include <config.h>,
  55    but that file should always be idempotent (i.e., it's just #define/#undef
  56    and nothing else anywhere should be changing the macro state it touches),
  57    so it's harmless.  */
  58 #define HAVE_CONFIG_H   0
  59
  60 /* Define this for the benefit of portable GNU code that wants to check it.
  61    Of course, it's never false when building libc!  */
  62 #define STDC_HEADERS    1
  63
  64 /* The symbols in all the user (non-_) macros are C symbols.  */
  65
  66 #if !defined HAVE_ASM_WEAK_DIRECTIVE && !defined HAVE_ASM_WEAKEXT_DIRECTIVE
  67 # error "weak symbol support needed"
  68 #endif
  69
  70 #ifndef __SYMBOL_PREFIX
  71 # define __SYMBOL_PREFIX
  72 #endif
  73
  74 #ifndef C_SYMBOL_NAME
  75 # define C_SYMBOL_NAME(name) name
  76 #endif
  77
  78 #ifndef ASM_LINE_SEP
  79 # define ASM_LINE_SEP ;
  80 #endif
  81
  82 #ifdef HAVE_ASM_GLOBAL_DOT_NAME
  83 # ifndef C_SYMBOL_DOT_NAME
  84 #  if defined __GNUC__ && defined __GNUC_MINOR__ \
  85       && (__GNUC__ << 16) + __GNUC_MINOR__ >= (3 << 16) + 1
  86 #   define C_SYMBOL_DOT_NAME(name) .name
  87 #  else
  88 #   define C_SYMBOL_DOT_NAME(name) .##name
  89 #  endif
  90 # endif
  91 #endif
  92
  93 #ifndef __ASSEMBLER__
  94 /* GCC understands weak symbols and aliases; use its interface where
  95    possible, instead of embedded assembly language.  */
  96
  97 /* Define ALIASNAME as a strong alias for NAME.  */
  98 # define strong_alias(name, aliasname) _strong_alias(name, aliasname)
  99 # define _strong_alias(name, aliasname) \
 100   extern __typeof (name) aliasname __attribute__ ((alias (#name)));
 101
 102 /* This comes between the return type and function name in
 103    a function definition to make that definition weak.  */
 104 # define weak_function __attribute__ ((weak))
 105 # define weak_const_function __attribute__ ((weak, __const__))
 106
 107 /* Define ALIASNAME as a weak alias for NAME.
 108    If weak aliases are not available, this defines a strong alias.  */
 109 # define weak_alias(name, aliasname) _weak_alias (name, aliasname)
 110 # define _weak_alias(name, aliasname) \
 111   extern __typeof (name) aliasname __attribute__ ((weak, alias (#name)));
 112
 113 /* Same as WEAK_ALIAS, but mark symbol as hidden.  */
 114 # define weak_hidden_alias(name, aliasname) \
 115   _weak_hidden_alias (name, aliasname)
 116 # define _weak_hidden_alias(name, aliasname) \
 117   extern __typeof (name) aliasname \
 118     __attribute__ ((weak, alias (#name), __visibility__ ("hidden")));
 119
 120 /* Declare SYMBOL as weak undefined symbol (resolved to 0 if not defined).  */
 121 # define weak_extern(symbol) _weak_extern (weak symbol)
 122 # define _weak_extern(expr) _Pragma (#expr)
 123
 124
 125 #else /* __ASSEMBLER__ */
 126
 127 # ifdef HAVE_ASM_SET_DIRECTIVE
 128 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 129 #   define strong_alias(original, alias)                                \
 130   .globl C_SYMBOL_NAME (alias) ASM_LINE_SEP             \
 131   .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original) ASM_LINE_SEP      \
 132   .globl C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP         \
 133   .set C_SYMBOL_DOT_NAME (alias),C_SYMBOL_DOT_NAME (original)
 134 #   define strong_data_alias(original, alias)                           \
 135   .globl C_SYMBOL_NAME (alias) ASM_LINE_SEP             \
 136   .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original)
 137 #  else
 138 #   define strong_alias(original, alias)                                \
 139   .globl C_SYMBOL_NAME (alias) ASM_LINE_SEP             \
 140   .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original)
 141 #   define strong_data_alias(original, alias) strong_alias(original, alias)
 142 #  endif
 143 # else
 144 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 145 #   define strong_alias(original, alias)                                \
 146   .globl C_SYMBOL_NAME (alias) ASM_LINE_SEP             \
 147   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original) ASM_LINE_SEP         \
 148   .globl C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP         \
 149   C_SYMBOL_DOT_NAME (alias) = C_SYMBOL_DOT_NAME (original)
 150 #   define strong_data_alias(original, alias)                           \
 151   .globl C_SYMBOL_NAME (alias) ASM_LINE_SEP             \
 152   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
 153 #  else
 154 #   define strong_alias(original, alias)                                \
 155   .globl C_SYMBOL_NAME (alias) ASM_LINE_SEP             \
 156   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
 157 #   define strong_data_alias(original, alias) strong_alias(original, alias)
 158 #  endif
 159 # endif
 160
 161 # ifdef HAVE_ASM_WEAKEXT_DIRECTIVE
 162 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 163 #   define weak_alias(original, alias)                                  \
 164   .weakext C_SYMBOL_NAME (alias), C_SYMBOL_NAME (original) ASM_LINE_SEP \
 165   .weakext C_SYMBOL_DOT_NAME (alias), C_SYMBOL_DOT_NAME (original)
 166 #  else
 167 #   define weak_alias(original, alias)                                  \
 168   .weakext C_SYMBOL_NAME (alias), C_SYMBOL_NAME (original)
 169 #  endif
 170 #  define weak_extern(symbol)                                           \
 171   .weakext C_SYMBOL_NAME (symbol)
 172
 173 # else /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
 174
 175 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 176 #   define weak_alias(original, alias)                                  \
 177   .weak C_SYMBOL_NAME (alias) ASM_LINE_SEP                              \
 178   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original) ASM_LINE_SEP         \
 179   .weak C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP                          \
 180   C_SYMBOL_DOT_NAME (alias) = C_SYMBOL_DOT_NAME (original)
 181 #  else
 182 #   define weak_alias(original, alias)                                  \
 183   .weak C_SYMBOL_NAME (alias) ASM_LINE_SEP                              \
 184   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
 185 #  endif
 186
 187 #  define weak_extern(symbol)                                           \
 188   .weak C_SYMBOL_NAME (symbol)
 189
 190 # endif /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
 191
 192 #endif /* __ASSEMBLER__ */
 193
 194 /* On some platforms we can make internal function calls (i.e., calls of
 195    functions not exported) a bit faster by using a different calling
 196    convention.  */
 197 #ifndef internal_function
 198 # define internal_function      /* empty */
 199 #endif
 200
 201 /* Determine the return address.  */
 202 #define RETURN_ADDRESS(nr) \
 203   __builtin_extract_return_addr (__builtin_return_address (nr))
 204
 205 /* When a reference to SYMBOL is encountered, the linker will emit a
 206    warning message MSG.  */
 207 /* We want the .gnu.warning.SYMBOL section to be unallocated.  */
 208 #ifdef HAVE_ASM_PREVIOUS_DIRECTIVE
 209 # define __make_section_unallocated(section_string)     \
 210   asm (".section " section_string "\n\t.previous");
 211 #elif defined HAVE_ASM_POPSECTION_DIRECTIVE
 212 # define __make_section_unallocated(section_string)     \
 213   asm (".pushsection " section_string "\n\t.popsection");
 214 #else
 215 # define __make_section_unallocated(section_string)
 216 #endif
 217
 218 /* Tacking on "\n\t#" to the section name makes gcc put it's bogus
 219    section attributes on what looks like a comment to the assembler.  */
 220 #ifdef HAVE_SECTION_QUOTES
 221 # define __sec_comment "\"\n\t#\""
 222 #else
 223 # define __sec_comment "\n\t#"
 224 #endif
 225 #define link_warning(symbol, msg) \
 226   __make_section_unallocated (".gnu.warning." #symbol) \
 227   static const char __evoke_link_warning_##symbol[]     \
 228     __attribute__ ((used, section (".gnu.warning." #symbol __sec_comment))) \
 229     = msg;
 230 #define libc_freeres_ptr(decl) \
 231   __make_section_unallocated ("__libc_freeres_ptrs, \"aw\", %nobits") \
 232   decl __attribute__ ((section ("__libc_freeres_ptrs" __sec_comment)))
 233 #define __libc_freeres_fn_section \
 234   __attribute__ ((section ("__libc_freeres_fn")))
 235
 236 #define libc_freeres_fn(name)   \
 237   static void name (void) __attribute_used__ __libc_freeres_fn_section; \
 238   text_set_element (__libc_subfreeres, name);                           \
 239   static void name (void)
 240
 241 /* A canned warning for sysdeps/stub functions.  */
 242 #define stub_warning(name) \
 243   __make_section_unallocated (".gnu.glibc-stub." #name) \
 244   link_warning (name, #name " is not implemented and will always fail")
 245
 246 /* Warning for linking functions calling dlopen into static binaries.  */
 247 #ifdef SHARED
 248 #define static_link_warning(name)
 249 #else
 250 #define static_link_warning(name) static_link_warning1(name)
 251 #define static_link_warning1(name) \
 252   link_warning(name, "Using '" #name "' in statically linked applications \
 253 requires at runtime the shared libraries from the glibc version used \
 254 for linking")
 255 #endif
 256
 257 /* Declare SYMBOL to be TYPE (`function' or `object') of SIZE bytes
 258    alias to ORIGINAL, when the assembler supports such declarations
 259    (such as in ELF).
 260    This is only necessary when defining something in assembly, or playing
 261    funny alias games where the size should be other than what the compiler
 262    thinks it is.  */
 263 #define declare_symbol_alias(symbol, original, type, size) \
 264   declare_symbol_alias_1 (symbol, original, type, size)
 265 #ifdef __ASSEMBLER__
 266 # define declare_symbol_alias_1(symbol, original, type, size) \
 267    strong_alias (original, symbol); \
 268    .type C_SYMBOL_NAME (symbol), %##type; \
 269    .size C_SYMBOL_NAME (symbol), size
 270 #else /* Not __ASSEMBLER__.  */
 271 # define declare_symbol_alias_1(symbol, original, type, size) \
 272    asm (".globl " __SYMBOL_PREFIX #symbol \
 273         "\n\t" declare_symbol_alias_1_alias (symbol, original) \
 274         "\n\t.type " __SYMBOL_PREFIX #symbol ", " \
 275         "%" #type \
 276         "\n\t.size " __SYMBOL_PREFIX #symbol ", " #size);
 277 # ifdef HAVE_ASM_SET_DIRECTIVE
 278 #  define declare_symbol_alias_1_alias(symbol, original) \
 279      ".set " __SYMBOL_PREFIX #symbol ", " __SYMBOL_PREFIX #original
 280 # else
 281 #  define declare_symbol_alias_1_alias(symbol, original) \
 282      __SYMBOL_PREFIX #symbol " = " __SYMBOL_PREFIX #original
 283 # endif /* HAVE_ASM_SET_DIRECTIVE */
 284 #endif /* __ASSEMBLER__ */
 285
 286
 287 /*
 288 \f
 289 */
 290
 291 /* Symbol set support macros.  */
 292
 293 /* Make SYMBOL, which is in the text segment, an element of SET.  */
 294 #define text_set_element(set, symbol)   _elf_set_element(set, symbol)
 295 /* Make SYMBOL, which is in the data segment, an element of SET.  */
 296 #define data_set_element(set, symbol)   _elf_set_element(set, symbol)
 297 /* Make SYMBOL, which is in the bss segment, an element of SET.  */
 298 #define bss_set_element(set, symbol)    _elf_set_element(set, symbol)
 299
 300 /* These are all done the same way in ELF.
 301    There is a new section created for each set.  */
 302 #ifdef SHARED
 303 /* When building a shared library, make the set section writable,
 304    because it will need to be relocated at run time anyway.  */
 305 # define _elf_set_element(set, symbol) \
 306   static const void *__elf_set_##set##_element_##symbol##__ \
 307     __attribute__ ((used, section (#set))) = &(symbol)
 308 #else
 309 # define _elf_set_element(set, symbol) \
 310   static const void *const __elf_set_##set##_element_##symbol##__ \
 311     __attribute__ ((used, section (#set))) = &(symbol)
 312 #endif
 313
 314 /* Define SET as a symbol set.  This may be required (it is in a.out) to
 315    be able to use the set's contents.  */
 316 #define symbol_set_define(set)  symbol_set_declare(set)
 317
 318 /* Declare SET for use in this module, if defined in another module.
 319    In a shared library, this is always local to that shared object.
 320    For static linking, the set might be wholly absent and so we use
 321    weak references.  */
 322 #define symbol_set_declare(set) \
 323   extern char const __start_##set[] __symbol_set_attribute; \
 324   extern char const __stop_##set[] __symbol_set_attribute;
 325 #ifdef SHARED
 326 # define __symbol_set_attribute attribute_hidden
 327 #else
 328 # define __symbol_set_attribute __attribute__ ((weak))
 329 #endif
 330
 331 /* Return a pointer (void *const *) to the first element of SET.  */
 332 #define symbol_set_first_element(set)   ((void *const *) (&__start_##set))
 333
 334 /* Return true iff PTR (a void *const *) has been incremented
 335    past the last element in SET.  */
 336 #define symbol_set_end_p(set, ptr) ((ptr) >= (void *const *) &__stop_##set)
 337
 338 #ifdef SHARED
 339 # define symbol_version(real, name, version) \
 340      _symbol_version(real, name, version)
 341 # define default_symbol_version(real, name, version) \
 342      _default_symbol_version(real, name, version)
 343 # ifdef __ASSEMBLER__
 344 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 345 #   define _symbol_version(real, name, version) \
 346      .symver real, name##@##version ASM_LINE_SEP                        \
 347      .symver C_SYMBOL_DOT_NAME(real), C_SYMBOL_DOT_NAME(name##@##version)
 348 #   define _default_symbol_version(real, name, version) \
 349      .symver real, name##@##@##version ASM_LINE_SEP                     \
 350      .symver C_SYMBOL_DOT_NAME(real), C_SYMBOL_DOT_NAME(name##@##@##version)
 351 #  else
 352 #   define _symbol_version(real, name, version) \
 353      .symver real, name##@##version
 354 #   define _default_symbol_version(real, name, version) \
 355      .symver real, name##@##@##version
 356 #  endif
 357 # else
 358 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 359 #   define _symbol_version(real, name, version) \
 360      __asm__ (".symver " #real "," #name "@" #version "\n\t"    \
 361               ".symver ." #real ",." #name "@" #version)
 362 #   define _default_symbol_version(real, name, version) \
 363      __asm__ (".symver " #real "," #name "@@" #version "\n\t"   \
 364               ".symver ." #real ",." #name "@@" #version)
 365 #  else
 366 #   define _symbol_version(real, name, version) \
 367      __asm__ (".symver " #real "," #name "@" #version)
 368 #   define _default_symbol_version(real, name, version) \
 369      __asm__ (".symver " #real "," #name "@@" #version)
 370 #  endif
 371 # endif
 372 #else
 373 # define symbol_version(real, name, version)
 374 # define default_symbol_version(real, name, version) \
 375   strong_alias(real, name)
 376 #endif
 377
 378 #if defined SHARED || defined LIBC_NONSHARED
 379 # define attribute_hidden __attribute__ ((visibility ("hidden")))
 380 #else
 381 # define attribute_hidden
 382 #endif
 383
 384 #define attribute_tls_model_ie __attribute__ ((tls_model ("initial-exec")))
 385
 386 #define attribute_relro __attribute__ ((section (".data.rel.ro")))
 387
 388 /* Handling on non-exported internal names.  We have to do this only
 389    for shared code.  */
 390 #ifdef SHARED
 391 # define INTUSE(name) name##_internal
 392 # define INTDEF(name) strong_alias (name, name##_internal)
 393 # define INTVARDEF(name) \
 394   _INTVARDEF (name, name##_internal)
 395 # define _INTVARDEF(name, aliasname) \
 396   extern __typeof (name) aliasname __attribute__ ((alias (#name), \
 397                                                    visibility ("hidden")));
 398 # define INTDEF2(name, newname) strong_alias (name, newname##_internal)
 399 # define INTVARDEF2(name, newname) _INTVARDEF (name, newname##_internal)
 400 #else
 401 # define INTUSE(name) name
 402 # define INTDEF(name)
 403 # define INTVARDEF(name)
 404 # define INTDEF2(name, newname)
 405 # define INTVARDEF2(name, newname)
 406 #endif
 407
 408 /* The following macros are used for PLT bypassing within libc.so
 409    (and if needed other libraries similarly).
 410    First of all, you need to have the function prototyped somewhere,
 411    say in foo/foo.h:
 412
 413    int foo (int __bar);
 414
 415    If calls to foo within libc.so should always go to foo defined in libc.so,
 416    then in include/foo.h you add:
 417
 418    libc_hidden_proto (foo)
 419
 420    line and after the foo function definition:
 421
 422    int foo (int __bar)
 423    {
 424      return __bar;
 425    }
 426    libc_hidden_def (foo)
 427
 428    or
 429
 430    int foo (int __bar)
 431    {
 432      return __bar;
 433    }
 434    libc_hidden_weak (foo)
 435
 436    Similarly for global data.  If references to foo within libc.so should
 437    always go to foo defined in libc.so, then in include/foo.h you add:
 438
 439    libc_hidden_proto (foo)
 440
 441    line and after foo's definition:
 442
 443    int foo = INITIAL_FOO_VALUE;
 444    libc_hidden_data_def (foo)
 445
 446    or
 447
 448    int foo = INITIAL_FOO_VALUE;
 449    libc_hidden_data_weak (foo)
 450
 451    If foo is normally just an alias (strong or weak) to some other function,
 452    you should use the normal strong_alias first, then add libc_hidden_def
 453    or libc_hidden_weak:
 454
 455    int baz (int __bar)
 456    {
 457      return __bar;
 458    }
 459    strong_alias (baz, foo)
 460    libc_hidden_weak (foo)
 461
 462    If the function should be internal to multiple objects, say ld.so and
 463    libc.so, the best way is to use:
 464
 465    #if !defined NOT_IN_libc || defined IS_IN_rtld
 466    hidden_proto (foo)
 467    #endif
 468
 469    in include/foo.h and the normal macros at all function definitions
 470    depending on what DSO they belong to.
 471
 472    If versioned_symbol macro is used to define foo,
 473    libc_hidden_ver macro should be used, as in:
 474
 475    int __real_foo (int __bar)
 476    {
 477      return __bar;
 478    }
 479    versioned_symbol (libc, __real_foo, foo, GLIBC_2_1);
 480    libc_hidden_ver (__real_foo, foo)  */
 481
 482 #if defined SHARED && !defined NO_HIDDEN
 483 # ifndef __ASSEMBLER__
 484 #  define __hidden_proto_hiddenattr(attrs...) \
 485   __attribute__ ((visibility ("hidden"), ##attrs))
 486 #  define hidden_proto(name, attrs...) \
 487   __hidden_proto (name, , __GI_##name, ##attrs)
 488 #  define hidden_tls_proto(name, attrs...) \
 489   __hidden_proto (name, __thread, __GI_##name, ##attrs)
 490 #  define __hidden_proto(name, thread, internal, attrs...)           \
 491   extern thread __typeof (name) name __asm__ (__hidden_asmname (#internal)) \
 492   __hidden_proto_hiddenattr (attrs);
 493 #  define __hidden_asmname(name) \
 494   __hidden_asmname1 (__USER_LABEL_PREFIX__, name)
 495 #  define __hidden_asmname1(prefix, name) __hidden_asmname2(prefix, name)
 496 #  define __hidden_asmname2(prefix, name) #prefix name
 497 #  define __hidden_ver1(local, internal, name) \
 498   extern __typeof (name) __EI_##name __asm__(__hidden_asmname (#internal)); \
 499   extern __typeof (name) __EI_##name \
 500         __attribute__((alias (__hidden_asmname (#local))))
 501 #  define hidden_ver(local, name)       __hidden_ver1(local, __GI_##name, name);
 502 #  define hidden_data_ver(local, name)  hidden_ver(local, name)
 503 #  define hidden_def(name)              __hidden_ver1(__GI_##name, name, name);
 504 #  define hidden_data_def(name)         hidden_def(name)
 505 #  define hidden_weak(name) \
 506         __hidden_ver1(__GI_##name, name, name) __attribute__((weak));
 507 #  define hidden_data_weak(name)        hidden_weak(name)
 508 #  define hidden_nolink(name, lib, version) \
 509   __hidden_nolink1 (__GI_##name, __EI_##name, name, VERSION_##lib##_##version)
 510 #  define __hidden_nolink1(local, internal, name, version) \
 511   __hidden_nolink2 (local, internal, name, version)
 512 #  define __hidden_nolink2(local, internal, name, version) \
 513   extern __typeof (name) internal __attribute__ ((alias (#local))); \
 514   __hidden_nolink3 (local, internal, #name "@" #version)
 515 #  define __hidden_nolink3(local, internal, vername) \
 516   __asm__ (".symver " #internal ", " vername);
 517 # else
 518 /* For assembly, we need to do the opposite of what we do in C:
 519    in assembly gcc __REDIRECT stuff is not in place, so functions
 520    are defined by its normal name and we need to create the
 521    __GI_* alias to it, in C __REDIRECT causes the function definition
 522    to use __GI_* name and we need to add alias to the real name.
 523    There is no reason to use hidden_weak over hidden_def in assembly,
 524    but we provide it for consistency with the C usage.
 525    hidden_proto doesn't make sense for assembly but the equivalent
 526    is to call via the HIDDEN_JUMPTARGET macro instead of JUMPTARGET.  */
 527 #  define hidden_def(name)      strong_alias (name, __GI_##name)
 528 #  define hidden_weak(name)     hidden_def (name)
 529 #  define hidden_ver(local, name) strong_alias (local, __GI_##name)
 530 #  define hidden_data_def(name) strong_data_alias (name, __GI_##name)
 531 #  define hidden_data_weak(name)        hidden_data_def (name)
 532 #  define hidden_data_ver(local, name) strong_data_alias (local, __GI_##name)
 533 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 534 #   define HIDDEN_JUMPTARGET(name) .__GI_##name
 535 #  else
 536 #   define HIDDEN_JUMPTARGET(name) __GI_##name
 537 #  endif
 538 # endif
 539 #else
 540 # ifndef __ASSEMBLER__
 541 #  define hidden_proto(name, attrs...)
 542 #  define hidden_tls_proto(name, attrs...)
 543 # else
 544 #  define HIDDEN_JUMPTARGET(name) JUMPTARGET(name)
 545 # endif /* Not  __ASSEMBLER__ */
 546 # define hidden_weak(name)
 547 # define hidden_def(name)
 548 # define hidden_ver(local, name)
 549 # define hidden_data_weak(name)
 550 # define hidden_data_def(name)
 551 # define hidden_data_ver(local, name)
 552 # define hidden_nolink(name, lib, version)
 553 #endif
 554
 555 #if !defined NOT_IN_libc
 556 # define libc_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 557 # define libc_hidden_tls_proto(name, attrs...) hidden_tls_proto (name, ##attrs)
 558 # define libc_hidden_def(name) hidden_def (name)
 559 # define libc_hidden_weak(name) hidden_weak (name)
 560 # ifdef LINK_OBSOLETE_RPC
 561    /* libc_hidden_nolink_sunrpc should only get used in sunrpc code.  */
 562 #  define libc_hidden_nolink_sunrpc(name, version) hidden_def (name)
 563 # else
 564 #  define libc_hidden_nolink_sunrpc(name, version) hidden_nolink (name, libc, version)
 565 # endif
 566 # define libc_hidden_ver(local, name) hidden_ver (local, name)
 567 # define libc_hidden_data_def(name) hidden_data_def (name)
 568 # define libc_hidden_data_weak(name) hidden_data_weak (name)
 569 # define libc_hidden_data_ver(local, name) hidden_data_ver (local, name)
 570 #else
 571 # define libc_hidden_proto(name, attrs...)
 572 # define libc_hidden_tls_proto(name, attrs...)
 573 # define libc_hidden_def(name)
 574 # define libc_hidden_weak(name)
 575 # define libc_hidden_ver(local, name)
 576 # define libc_hidden_data_def(name)
 577 # define libc_hidden_data_weak(name)
 578 # define libc_hidden_data_ver(local, name)
 579 #endif
 580
 581 #if defined NOT_IN_libc && defined IS_IN_rtld
 582 # define rtld_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 583 # define rtld_hidden_tls_proto(name, attrs...) hidden_tls_proto (name, ##attrs)
 584 # define rtld_hidden_def(name) hidden_def (name)
 585 # define rtld_hidden_weak(name) hidden_weak (name)
 586 # define rtld_hidden_ver(local, name) hidden_ver (local, name)
 587 # define rtld_hidden_data_def(name) hidden_data_def (name)
 588 # define rtld_hidden_data_weak(name) hidden_data_weak (name)
 589 # define rtld_hidden_data_ver(local, name) hidden_data_ver (local, name)
 590 #else
 591 # define rtld_hidden_proto(name, attrs...)
 592 # define rtld_hidden_tls_proto(name, attrs...)
 593 # define rtld_hidden_def(name)
 594 # define rtld_hidden_weak(name)
 595 # define rtld_hidden_ver(local, name)
 596 # define rtld_hidden_data_def(name)
 597 # define rtld_hidden_data_weak(name)
 598 # define rtld_hidden_data_ver(local, name)
 599 #endif
 600
 601 #if defined NOT_IN_libc && defined IS_IN_libm
 602 # define libm_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 603 # define libm_hidden_tls_proto(name, attrs...) hidden_tls_proto (name, ##attrs)
 604 # define libm_hidden_def(name) hidden_def (name)
 605 # define libm_hidden_weak(name) hidden_weak (name)
 606 # define libm_hidden_ver(local, name) hidden_ver (local, name)
 607 # define libm_hidden_data_def(name) hidden_data_def (name)
 608 # define libm_hidden_data_weak(name) hidden_data_weak (name)
 609 # define libm_hidden_data_ver(local, name) hidden_data_ver (local, name)
 610 #else
 611 # define libm_hidden_proto(name, attrs...)
 612 # define libm_hidden_tls_proto(name, attrs...)
 613 # define libm_hidden_def(name)
 614 # define libm_hidden_weak(name)
 615 # define libm_hidden_ver(local, name)
 616 # define libm_hidden_data_def(name)
 617 # define libm_hidden_data_weak(name)
 618 # define libm_hidden_data_ver(local, name)
 619 #endif
 620
 621 #if defined NOT_IN_libc && defined IS_IN_libresolv
 622 # define libresolv_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 623 # define libresolv_hidden_tls_proto(name, attrs...) \
 624   hidden_tls_proto (name, ##attrs)
 625 # define libresolv_hidden_def(name) hidden_def (name)
 626 # define libresolv_hidden_weak(name) hidden_weak (name)
 627 # define libresolv_hidden_ver(local, name) hidden_ver (local, name)
 628 # define libresolv_hidden_data_def(name) hidden_data_def (name)
 629 # define libresolv_hidden_data_weak(name) hidden_data_weak (name)
 630 # define libresolv_hidden_data_ver(local, name) hidden_data_ver (local, name)
 631 #else
 632 # define libresolv_hidden_proto(name, attrs...)
 633 # define libresolv_hidden_tls_proto(name, attrs...)
 634 # define libresolv_hidden_def(name)
 635 # define libresolv_hidden_weak(name)
 636 # define libresolv_hidden_ver(local, name)
 637 # define libresolv_hidden_data_def(name)
 638 # define libresolv_hidden_data_weak(name)
 639 # define libresolv_hidden_data_ver(local, name)
 640 #endif
 641
 642 #if defined NOT_IN_libc && defined IS_IN_librt
 643 # define librt_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 644 # define librt_hidden_tls_proto(name, attrs...) \
 645   hidden_tls_proto (name, ##attrs)
 646 # define librt_hidden_def(name) hidden_def (name)
 647 # define librt_hidden_weak(name) hidden_weak (name)
 648 # define librt_hidden_ver(local, name) hidden_ver (local, name)
 649 # define librt_hidden_data_def(name) hidden_data_def (name)
 650 # define librt_hidden_data_weak(name) hidden_data_weak (name)
 651 # define librt_hidden_data_ver(local, name) hidden_data_ver (local, name)
 652 #else
 653 # define librt_hidden_proto(name, attrs...)
 654 # define librt_hidden_tls_proto(name, attrs...)
 655 # define librt_hidden_def(name)
 656 # define librt_hidden_weak(name)
 657 # define librt_hidden_ver(local, name)
 658 # define librt_hidden_data_def(name)
 659 # define librt_hidden_data_weak(name)
 660 # define librt_hidden_data_ver(local, name)
 661 #endif
 662
 663 #if defined NOT_IN_libc && defined IS_IN_libdl
 664 # define libdl_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 665 # define libdl_hidden_tls_proto(name, attrs...) \
 666   hidden_tls_proto (name, ##attrs)
 667 # define libdl_hidden_def(name) hidden_def (name)
 668 # define libdl_hidden_weak(name) hidden_weak (name)
 669 # define libdl_hidden_ver(local, name) hidden_ver (local, name)
 670 # define libdl_hidden_data_def(name) hidden_data_def (name)
 671 # define libdl_hidden_data_weak(name) hidden_data_weak (name)
 672 # define libdl_hidden_data_ver(local, name) hidden_data_ver (local, name)
 673 #else
 674 # define libdl_hidden_proto(name, attrs...)
 675 # define libdl_hidden_tls_proto(name, attrs...)
 676 # define libdl_hidden_def(name)
 677 # define libdl_hidden_weak(name)
 678 # define libdl_hidden_ver(local, name)
 679 # define libdl_hidden_data_def(name)
 680 # define libdl_hidden_data_weak(name)
 681 # define libdl_hidden_data_ver(local, name)
 682 #endif
 683
 684 #if defined NOT_IN_libc && defined IS_IN_libnss_files
 685 # define libnss_files_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 686 # define libnss_files_hidden_tls_proto(name, attrs...) \
 687   hidden_tls_proto (name, ##attrs)
 688 # define libnss_files_hidden_def(name) hidden_def (name)
 689 # define libnss_files_hidden_weak(name) hidden_weak (name)
 690 # define libnss_files_hidden_ver(local, name) hidden_ver (local, name)
 691 # define libnss_files_hidden_data_def(name) hidden_data_def (name)
 692 # define libnss_files_hidden_data_weak(name) hidden_data_weak (name)
 693 # define libnss_files_hidden_data_ver(local, name) hidden_data_ver(local, name)
 694 #else
 695 # define libnss_files_hidden_proto(name, attrs...)
 696 # define libnss_files_hidden_tls_proto(name, attrs...)
 697 # define libnss_files_hidden_def(name)
 698 # define libnss_files_hidden_weak(name)
 699 # define libnss_files_hidden_ver(local, name)
 700 # define libnss_files_hidden_data_def(name)
 701 # define libnss_files_hidden_data_weak(name)
 702 # define libnss_files_hidden_data_ver(local, name)
 703 #endif
 704
 705 #if defined NOT_IN_libc && defined IS_IN_libnsl
 706 # define libnsl_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 707 # define libnsl_hidden_tls_proto(name, attrs...) \
 708   hidden_tls_proto (name, ##attrs)
 709 # define libnsl_hidden_def(name) hidden_def (name)
 710 # define libnsl_hidden_weak(name) hidden_weak (name)
 711 # define libnsl_hidden_ver(local, name) hidden_ver (local, name)
 712 # define libnsl_hidden_data_def(name) hidden_data_def (name)
 713 # define libnsl_hidden_data_weak(name) hidden_data_weak (name)
 714 # define libnsl_hidden_data_ver(local, name) hidden_data_ver (local, name)
 715 #else
 716 # define libnsl_hidden_proto(name, attrs...)
 717 # define libnsl_hidden_tls_proto(name, attrs...)
 718 # define libnsl_hidden_def(name)
 719 # define libnsl_hidden_weak(name)
 720 # define libnsl_hidden_ver(local, name)
 721 # define libnsl_hidden_data_def(name)
 722 # define libnsl_hidden_data_weak(name)
 723 # define libnsl_hidden_data_ver(local, name)
 724 #endif
 725
 726 #if defined NOT_IN_libc && defined IS_IN_libnss_nisplus
 727 # define libnss_nisplus_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 728 # define libnss_nisplus_hidden_tls_proto(name, attrs...) \
 729   hidden_tls_proto (name, ##attrs)
 730 # define libnss_nisplus_hidden_def(name) hidden_def (name)
 731 # define libnss_nisplus_hidden_weak(name) hidden_weak (name)
 732 # define libnss_nisplus_hidden_ver(local, name) hidden_ver (local, name)
 733 # define libnss_nisplus_hidden_data_def(name) hidden_data_def (name)
 734 # define libnss_nisplus_hidden_data_weak(name) hidden_data_weak (name)
 735 # define libnss_nisplus_hidden_data_ver(local, name) hidden_data_ver (local, name)
 736 #else
 737 # define libnss_nisplus_hidden_proto(name, attrs...)
 738 # define libnss_nisplus_hidden_tls_proto(name, attrs...)
 739 # define libnss_nisplus_hidden_def(name)
 740 # define libnss_nisplus_hidden_weak(name)
 741 # define libnss_nisplus_hidden_ver(local, name)
 742 # define libnss_nisplus_hidden_data_def(name)
 743 # define libnss_nisplus_hidden_data_weak(name)
 744 # define libnss_nisplus_hidden_data_ver(local, name)
 745 #endif
 746
 747 #define libc_hidden_builtin_proto(name, attrs...) libc_hidden_proto (name, ##attrs)
 748 #define libc_hidden_builtin_def(name) libc_hidden_def (name)
 749 #define libc_hidden_builtin_weak(name) libc_hidden_weak (name)
 750 #define libc_hidden_builtin_ver(local, name) libc_hidden_ver (local, name)
 751 #ifdef __ASSEMBLER__
 752 # define HIDDEN_BUILTIN_JUMPTARGET(name) HIDDEN_JUMPTARGET(name)
 753 #endif
 754
 755 #if defined NOT_IN_libc && defined IS_IN_libutil
 756 # define libutil_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 757 # define libutil_hidden_tls_proto(name, attrs...) \
 758   hidden_tls_proto (name, ##attrs)
 759 # define libutil_hidden_def(name) hidden_def (name)
 760 # define libutil_hidden_weak(name) hidden_weak (name)
 761 # define libutil_hidden_ver(local, name) hidden_ver (local, name)
 762 # define libutil_hidden_data_def(name) hidden_data_def (name)
 763 # define libutil_hidden_data_weak(name) hidden_data_weak (name)
 764 # define libutil_hidden_data_ver(local, name) hidden_data_ver (local, name)
 765 #else
 766 # define libutil_hidden_proto(name, attrs...)
 767 # define libutil_hidden_tls_proto(name, attrs...)
 768 # define libutil_hidden_def(name)
 769 # define libutil_hidden_weak(name)
 770 # define libutil_hidden_ver(local, name)
 771 # define libutil_hidden_data_def(name)
 772 # define libutil_hidden_data_weak(name)
 773 # define libutil_hidden_data_ver(local, name)
 774 #endif
 775
 776 /* Get some dirty hacks.  */
 777 #include <symbol-hacks.h>
 778
 779 /* Move compatibility symbols out of the way by placing them all in a
 780    special section.  */
 781 #ifndef __ASSEMBLER__
 782 # define attribute_compat_text_section \
 783     __attribute__ ((section (".text.compat")))
 784 # define attribute_compat_data_section \
 785     __attribute__ ((section (".data.compat")))
 786 #else
 787 # define compat_text_section .section ".text.compat", "ax";
 788 # define compat_data_section .section ".data.compat", "aw";
 789 #endif
 790
 791 /* Marker used for indirection function symbols.  */
 792 #define libc_ifunc(name, expr)                                          \
 793   extern void *name##_ifunc (void) __asm__ (#name);                     \
 794   void *name##_ifunc (void)                                             \
 795   {                                                                     \
 796     INIT_ARCH ();                                                       \
 797     __typeof (name) *res = expr;                                        \
 798     return res;                                                         \
 799   }                                                                     \
 800   __asm__ (".type " #name ", %gnu_indirect_function");
 801
 802 /* The body of the function is supposed to use __get_cpu_features
 803    which will, if necessary, initialize the data first.  */
 804 #define libm_ifunc(name, expr)                                          \
 805   extern void *name##_ifunc (void) __asm__ (#name);                     \
 806   void *name##_ifunc (void)                                             \
 807   {                                                                     \
 808     __typeof (name) *res = expr;                                        \
 809     return res;                                                         \
 810   }                                                                     \
 811   __asm__ (".type " #name ", %gnu_indirect_function");
 812
 813 #ifdef HAVE_ASM_SET_DIRECTIVE
 814 # define libc_ifunc_hidden_def1(local, name)                            \
 815     __asm__ (".globl " #local "\n\t"                                    \
 816              ".hidden " #local "\n\t"                                   \
 817              ".set " #local ", " #name);
 818 #else
 819 # define libc_ifunc_hidden_def1(local, name)                            \
 820     __asm__ (".globl " #local "\n\t"                                    \
 821              ".hidden " #local "\n\t"                                   \
 822              #local " = " #name);
 823 #endif
 824
 825 #define libc_ifunc_hidden_def(name) \
 826   libc_ifunc_hidden_def1 (__GI_##name, name)
 827
 828 /* Add the compiler optimization to inhibit loop transformation to library
 829    calls.  This is used to avoid recursive calls in memset and memmove
 830    default implementations.  */
 831 #ifdef HAVE_CC_INHIBIT_LOOP_TO_LIBCALL
 832 # define inhibit_loop_to_libcall \
 833     __attribute__ ((__optimize__ ("-fno-tree-loop-distribute-patterns")))
 834 #else
 835 # define inhibit_loop_to_libcall
 836 #endif
 837
 838 #endif /* libc-symbols.h */