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) 1995-2012 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    * ASM_GLOBAL_DIRECTIVE with `.globl' or `.global'.
  31    * ASM_TYPE_DIRECTIVE_PREFIX with `@' or `#' or whatever for .type,
  32      or leave it undefined if there is no .type directive.
  33    * HAVE_ASM_WEAK_DIRECTIVE if we have weak symbols using `.weak'.
  34    * HAVE_ASM_WEAKEXT_DIRECTIVE if we have weak symbols using `.weakext'.
  35
  36    */
  37
  38 /* This is defined for the compilation of all C library code.  features.h
  39    tests this to avoid inclusion of stubs.h while compiling the library,
  40    before stubs.h has been generated.  Some library code that is shared
  41    with other packages also tests this symbol to see if it is being
  42    compiled as part of the C library.  We must define this before including
  43    config.h, because it makes some definitions conditional on whether libc
  44    itself is being compiled, or just some generator program.  */
  45 #define _LIBC   1
  46
  47 /* Enable declarations of GNU extensions, since we are compiling them.  */
  48 #define _GNU_SOURCE     1
  49 /* And we also need the data for the reentrant functions.  */
  50 #define _REENTRANT      1
  51
  52 #include <config.h>
  53
  54 /* The symbols in all the user (non-_) macros are C symbols.  */
  55
  56 #if !defined HAVE_ASM_WEAK_DIRECTIVE && !defined HAVE_ASM_WEAKEXT_DIRECTIVE
  57 # error "weak symbol support needed"
  58 #endif
  59
  60 #ifndef __SYMBOL_PREFIX
  61 # define __SYMBOL_PREFIX
  62 #endif
  63
  64 #ifndef C_SYMBOL_NAME
  65 # define C_SYMBOL_NAME(name) name
  66 #endif
  67
  68 #ifndef ASM_LINE_SEP
  69 # define ASM_LINE_SEP ;
  70 #endif
  71
  72 #ifdef HAVE_ASM_GLOBAL_DOT_NAME
  73 # ifndef C_SYMBOL_DOT_NAME
  74 #  if defined __GNUC__ && defined __GNUC_MINOR__ \
  75       && (__GNUC__ << 16) + __GNUC_MINOR__ >= (3 << 16) + 1
  76 #   define C_SYMBOL_DOT_NAME(name) .name
  77 #  else
  78 #   define C_SYMBOL_DOT_NAME(name) .##name
  79 #  endif
  80 # endif
  81 #endif
  82
  83 #ifndef __ASSEMBLER__
  84 /* GCC understands weak symbols and aliases; use its interface where
  85    possible, instead of embedded assembly language.  */
  86
  87 /* Define ALIASNAME as a strong alias for NAME.  */
  88 # define strong_alias(name, aliasname) _strong_alias(name, aliasname)
  89 # define _strong_alias(name, aliasname) \
  90   extern __typeof (name) aliasname __attribute__ ((alias (#name)));
  91
  92 /* This comes between the return type and function name in
  93    a function definition to make that definition weak.  */
  94 # define weak_function __attribute__ ((weak))
  95 # define weak_const_function __attribute__ ((weak, __const__))
  96
  97 /* Define ALIASNAME as a weak alias for NAME.
  98    If weak aliases are not available, this defines a strong alias.  */
  99 # define weak_alias(name, aliasname) _weak_alias (name, aliasname)
 100 # define _weak_alias(name, aliasname) \
 101   extern __typeof (name) aliasname __attribute__ ((weak, alias (#name)));
 102
 103 /* Same as WEAK_ALIAS, but mark symbol as hidden.  */
 104 # define weak_hidden_alias(name, aliasname) \
 105   _weak_hidden_alias (name, aliasname)
 106 # define _weak_hidden_alias(name, aliasname) \
 107   extern __typeof (name) aliasname \
 108     __attribute__ ((weak, alias (#name), __visibility__ ("hidden")));
 109
 110 /* Declare SYMBOL as weak undefined symbol (resolved to 0 if not defined).  */
 111 # define weak_extern(symbol) _weak_extern (weak symbol)
 112 # define _weak_extern(expr) _Pragma (#expr)
 113
 114
 115 #else /* __ASSEMBLER__ */
 116
 117 # ifdef HAVE_ASM_SET_DIRECTIVE
 118 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 119 #   define strong_alias(original, alias)                                \
 120   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 121   .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original) ASM_LINE_SEP      \
 122   ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP           \
 123   .set C_SYMBOL_DOT_NAME (alias),C_SYMBOL_DOT_NAME (original)
 124 #   define strong_data_alias(original, alias)                           \
 125   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 126   .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original)
 127 #  else
 128 #   define strong_alias(original, alias)                                \
 129   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 130   .set C_SYMBOL_NAME (alias),C_SYMBOL_NAME (original)
 131 #   define strong_data_alias(original, alias) strong_alias(original, alias)
 132 #  endif
 133 # else
 134 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 135 #   define strong_alias(original, alias)                                \
 136   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 137   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original) ASM_LINE_SEP         \
 138   ASM_GLOBAL_DIRECTIVE C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP           \
 139   C_SYMBOL_DOT_NAME (alias) = C_SYMBOL_DOT_NAME (original)
 140 #   define strong_data_alias(original, alias)                           \
 141   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 142   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
 143 #  else
 144 #   define strong_alias(original, alias)                                \
 145   ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME (alias) ASM_LINE_SEP               \
 146   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
 147 #   define strong_data_alias(original, alias) strong_alias(original, alias)
 148 #  endif
 149 # endif
 150
 151 # ifdef HAVE_ASM_WEAKEXT_DIRECTIVE
 152 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 153 #   define weak_alias(original, alias)                                  \
 154   .weakext C_SYMBOL_NAME (alias), C_SYMBOL_NAME (original) ASM_LINE_SEP \
 155   .weakext C_SYMBOL_DOT_NAME (alias), C_SYMBOL_DOT_NAME (original)
 156 #  else
 157 #   define weak_alias(original, alias)                                  \
 158   .weakext C_SYMBOL_NAME (alias), C_SYMBOL_NAME (original)
 159 #  endif
 160 #  define weak_extern(symbol)                                           \
 161   .weakext C_SYMBOL_NAME (symbol)
 162
 163 # else /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
 164
 165 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 166 #   define weak_alias(original, alias)                                  \
 167   .weak C_SYMBOL_NAME (alias) ASM_LINE_SEP                              \
 168   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original) ASM_LINE_SEP         \
 169   .weak C_SYMBOL_DOT_NAME (alias) ASM_LINE_SEP                          \
 170   C_SYMBOL_DOT_NAME (alias) = C_SYMBOL_DOT_NAME (original)
 171 #  else
 172 #   define weak_alias(original, alias)                                  \
 173   .weak C_SYMBOL_NAME (alias) ASM_LINE_SEP                              \
 174   C_SYMBOL_NAME (alias) = C_SYMBOL_NAME (original)
 175 #  endif
 176
 177 #  define weak_extern(symbol)                                           \
 178   .weak C_SYMBOL_NAME (symbol)
 179
 180 # endif /* ! HAVE_ASM_WEAKEXT_DIRECTIVE */
 181
 182 #endif /* __ASSEMBLER__ */
 183
 184 /* On some platforms we can make internal function calls (i.e., calls of
 185    functions not exported) a bit faster by using a different calling
 186    convention.  */
 187 #ifndef internal_function
 188 # define internal_function      /* empty */
 189 #endif
 190
 191 /* Determine the return address.  */
 192 #define RETURN_ADDRESS(nr) \
 193   __builtin_extract_return_addr (__builtin_return_address (nr))
 194
 195 /* When a reference to SYMBOL is encountered, the linker will emit a
 196    warning message MSG.  */
 197 /* We want the .gnu.warning.SYMBOL section to be unallocated.  */
 198 #ifdef HAVE_ASM_PREVIOUS_DIRECTIVE
 199 # define __make_section_unallocated(section_string)     \
 200   asm (".section " section_string "\n\t.previous");
 201 #elif defined HAVE_ASM_POPSECTION_DIRECTIVE
 202 # define __make_section_unallocated(section_string)     \
 203   asm (".pushsection " section_string "\n\t.popsection");
 204 #else
 205 # define __make_section_unallocated(section_string)
 206 #endif
 207
 208 /* Tacking on "\n\t#" to the section name makes gcc put it's bogus
 209    section attributes on what looks like a comment to the assembler.  */
 210 #ifdef HAVE_SECTION_QUOTES
 211 # define __sec_comment "\"\n\t#\""
 212 #else
 213 # define __sec_comment "\n\t#"
 214 #endif
 215 #define link_warning(symbol, msg) \
 216   __make_section_unallocated (".gnu.warning." #symbol) \
 217   static const char __evoke_link_warning_##symbol[]     \
 218     __attribute__ ((used, section (".gnu.warning." #symbol __sec_comment))) \
 219     = msg;
 220 #define libc_freeres_ptr(decl) \
 221   __make_section_unallocated ("__libc_freeres_ptrs, \"aw\", %nobits") \
 222   decl __attribute__ ((section ("__libc_freeres_ptrs" __sec_comment)))
 223 #define __libc_freeres_fn_section \
 224   __attribute__ ((section ("__libc_freeres_fn")))
 225
 226 #define libc_freeres_fn(name)   \
 227   static void name (void) __attribute_used__ __libc_freeres_fn_section; \
 228   text_set_element (__libc_subfreeres, name);                           \
 229   static void name (void)
 230
 231 /* A canned warning for sysdeps/stub functions.  */
 232 #define stub_warning(name) \
 233   __make_section_unallocated (".gnu.glibc-stub." #name) \
 234   link_warning (name, \
 235                 "warning: " #name " is not implemented and will always fail")
 236
 237 /* Warning for linking functions calling dlopen into static binaries.  */
 238 #ifdef SHARED
 239 #define static_link_warning(name)
 240 #else
 241 #define static_link_warning(name) static_link_warning1(name)
 242 #define static_link_warning1(name) \
 243   link_warning(name, "Using '" #name "' in statically linked applications \
 244 requires at runtime the shared libraries from the glibc version used \
 245 for linking")
 246 #endif
 247
 248 /* Declare SYMBOL to be TYPE (`function' or `object') of SIZE bytes
 249    alias to ORIGINAL, when the assembler supports such declarations
 250    (such as in ELF).
 251    This is only necessary when defining something in assembly, or playing
 252    funny alias games where the size should be other than what the compiler
 253    thinks it is.  */
 254 #define declare_symbol_alias(symbol, original, type, size) \
 255   declare_symbol_alias_1 (symbol, original, type, size)
 256 #ifdef ASM_TYPE_DIRECTIVE_PREFIX
 257 # ifdef __ASSEMBLER__
 258 #  define declare_symbol_alias_1(symbol, original, type, size) \
 259     strong_alias (original, symbol); \
 260     .type C_SYMBOL_NAME (symbol), \
 261           declare_symbol_alias_1_paste (ASM_TYPE_DIRECTIVE_PREFIX, type); \
 262     .size C_SYMBOL_NAME (symbol), size
 263 #  define declare_symbol_alias_1_paste(a, b) \
 264   declare_symbol_alias_1_paste_1 (a,b)
 265 #  define declare_symbol_alias_1_paste_1(a,b)   a##b
 266 # else /* Not __ASSEMBLER__.  */
 267 #  define declare_symbol_alias_1(symbol, original, type, size) \
 268     asm (declare_symbol_alias_1_stringify (ASM_GLOBAL_DIRECTIVE) \
 269          " " __SYMBOL_PREFIX #symbol \
 270          "\n\t" declare_symbol_alias_1_alias (symbol, original) \
 271          "\n\t.type " __SYMBOL_PREFIX #symbol ", " \
 272          declare_symbol_alias_1_stringify (ASM_TYPE_DIRECTIVE_PREFIX) #type \
 273          "\n\t.size " __SYMBOL_PREFIX #symbol ", " #size);
 274 #  define declare_symbol_alias_1_stringify(x) \
 275   declare_symbol_alias_1_stringify_1 (x)
 276 #  define declare_symbol_alias_1_stringify_1(x) #x
 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 #else
 286 # define declare_symbol_1(symbol, type, size) /* Nothing.  */
 287 #endif
 288
 289
 290 /*
 291 \f
 292 */
 293
 294 /* Symbol set support macros.  */
 295
 296 /* Make SYMBOL, which is in the text segment, an element of SET.  */
 297 #define text_set_element(set, symbol)   _elf_set_element(set, symbol)
 298 /* Make SYMBOL, which is in the data segment, an element of SET.  */
 299 #define data_set_element(set, symbol)   _elf_set_element(set, symbol)
 300 /* Make SYMBOL, which is in the bss segment, an element of SET.  */
 301 #define bss_set_element(set, symbol)    _elf_set_element(set, symbol)
 302
 303 /* These are all done the same way in ELF.
 304    There is a new section created for each set.  */
 305 #ifdef SHARED
 306 /* When building a shared library, make the set section writable,
 307    because it will need to be relocated at run time anyway.  */
 308 # define _elf_set_element(set, symbol) \
 309   static const void *__elf_set_##set##_element_##symbol##__ \
 310     __attribute__ ((used, section (#set))) = &(symbol)
 311 #else
 312 # define _elf_set_element(set, symbol) \
 313   static const void *const __elf_set_##set##_element_##symbol##__ \
 314     __attribute__ ((used, section (#set))) = &(symbol)
 315 #endif
 316
 317 /* Define SET as a symbol set.  This may be required (it is in a.out) to
 318    be able to use the set's contents.  */
 319 #define symbol_set_define(set)  symbol_set_declare(set)
 320
 321 /* Declare SET for use in this module, if defined in another module.
 322    In a shared library, this is always local to that shared object.
 323    For static linking, the set might be wholly absent and so we use
 324    weak references.  */
 325 #define symbol_set_declare(set) \
 326   extern char const __start_##set[] __symbol_set_attribute; \
 327   extern char const __stop_##set[] __symbol_set_attribute;
 328 #ifdef SHARED
 329 # define __symbol_set_attribute attribute_hidden
 330 #else
 331 # define __symbol_set_attribute __attribute__ ((weak))
 332 #endif
 333
 334 /* Return a pointer (void *const *) to the first element of SET.  */
 335 #define symbol_set_first_element(set)   ((void *const *) (&__start_##set))
 336
 337 /* Return true iff PTR (a void *const *) has been incremented
 338    past the last element in SET.  */
 339 #define symbol_set_end_p(set, ptr) ((ptr) >= (void *const *) &__stop_##set)
 340
 341 #if DO_VERSIONING
 342 # define symbol_version(real, name, version) \
 343      _symbol_version(real, name, version)
 344 # define default_symbol_version(real, name, version) \
 345      _default_symbol_version(real, name, version)
 346 # ifdef __ASSEMBLER__
 347 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 348 #   define _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 #   define _default_symbol_version(real, name, version) \
 352      .symver real, name##@##@##version ASM_LINE_SEP                     \
 353      .symver C_SYMBOL_DOT_NAME(real), C_SYMBOL_DOT_NAME(name##@##@##version)
 354 #  else
 355 #   define _symbol_version(real, name, version) \
 356      .symver real, name##@##version
 357 #   define _default_symbol_version(real, name, version) \
 358      .symver real, name##@##@##version
 359 #  endif
 360 # else
 361 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 362 #   define _symbol_version(real, name, version) \
 363      __asm__ (".symver " #real "," #name "@" #version "\n\t"    \
 364               ".symver ." #real ",." #name "@" #version)
 365 #   define _default_symbol_version(real, name, version) \
 366      __asm__ (".symver " #real "," #name "@@" #version "\n\t"   \
 367               ".symver ." #real ",." #name "@@" #version)
 368 #  else
 369 #   define _symbol_version(real, name, version) \
 370      __asm__ (".symver " #real "," #name "@" #version)
 371 #   define _default_symbol_version(real, name, version) \
 372      __asm__ (".symver " #real "," #name "@@" #version)
 373 #  endif
 374 # endif
 375 #else
 376 # define symbol_version(real, name, version)
 377 # define default_symbol_version(real, name, version) \
 378   strong_alias(real, name)
 379 #endif
 380
 381 #if defined SHARED || defined LIBC_NONSHARED
 382 # define attribute_hidden __attribute__ ((visibility ("hidden")))
 383 #else
 384 # define attribute_hidden
 385 #endif
 386
 387 #define attribute_tls_model_ie __attribute__ ((tls_model ("initial-exec")))
 388
 389 #define attribute_relro __attribute__ ((section (".data.rel.ro")))
 390
 391 /* Handling on non-exported internal names.  We have to do this only
 392    for shared code.  */
 393 #ifdef SHARED
 394 # define INTUSE(name) name##_internal
 395 # define INTDEF(name) strong_alias (name, name##_internal)
 396 # define INTVARDEF(name) \
 397   _INTVARDEF (name, name##_internal)
 398 # define _INTVARDEF(name, aliasname) \
 399   extern __typeof (name) aliasname __attribute__ ((alias (#name), \
 400                                                    visibility ("hidden")));
 401 # define INTDEF2(name, newname) strong_alias (name, newname##_internal)
 402 # define INTVARDEF2(name, newname) _INTVARDEF (name, newname##_internal)
 403 #else
 404 # define INTUSE(name) name
 405 # define INTDEF(name)
 406 # define INTVARDEF(name)
 407 # define INTDEF2(name, newname)
 408 # define INTVARDEF2(name, newname)
 409 #endif
 410
 411 /* The following macros are used for PLT bypassing within libc.so
 412    (and if needed other libraries similarly).
 413    First of all, you need to have the function prototyped somewhere,
 414    say in foo/foo.h:
 415
 416    int foo (int __bar);
 417
 418    If calls to foo within libc.so should always go to foo defined in libc.so,
 419    then in include/foo.h you add:
 420
 421    libc_hidden_proto (foo)
 422
 423    line and after the foo function definition:
 424
 425    int foo (int __bar)
 426    {
 427      return __bar;
 428    }
 429    libc_hidden_def (foo)
 430
 431    or
 432
 433    int foo (int __bar)
 434    {
 435      return __bar;
 436    }
 437    libc_hidden_weak (foo)
 438
 439    Similarly for global data.  If references to foo within libc.so should
 440    always go to foo defined in libc.so, then in include/foo.h you add:
 441
 442    libc_hidden_proto (foo)
 443
 444    line and after foo's definition:
 445
 446    int foo = INITIAL_FOO_VALUE;
 447    libc_hidden_data_def (foo)
 448
 449    or
 450
 451    int foo = INITIAL_FOO_VALUE;
 452    libc_hidden_data_weak (foo)
 453
 454    If foo is normally just an alias (strong or weak) to some other function,
 455    you should use the normal strong_alias first, then add libc_hidden_def
 456    or libc_hidden_weak:
 457
 458    int baz (int __bar)
 459    {
 460      return __bar;
 461    }
 462    strong_alias (baz, foo)
 463    libc_hidden_weak (foo)
 464
 465    If the function should be internal to multiple objects, say ld.so and
 466    libc.so, the best way is to use:
 467
 468    #if !defined NOT_IN_libc || defined IS_IN_rtld
 469    hidden_proto (foo)
 470    #endif
 471
 472    in include/foo.h and the normal macros at all function definitions
 473    depending on what DSO they belong to.
 474
 475    If versioned_symbol macro is used to define foo,
 476    libc_hidden_ver macro should be used, as in:
 477
 478    int __real_foo (int __bar)
 479    {
 480      return __bar;
 481    }
 482    versioned_symbol (libc, __real_foo, foo, GLIBC_2_1);
 483    libc_hidden_ver (__real_foo, foo)  */
 484
 485 #if defined SHARED && defined DO_VERSIONING && !defined NO_HIDDEN
 486 # ifndef __ASSEMBLER__
 487 #  define __hidden_proto_hiddenattr(attrs...) \
 488   __attribute__ ((visibility ("hidden"), ##attrs))
 489 #  define hidden_proto(name, attrs...) \
 490   __hidden_proto (name, __GI_##name, ##attrs)
 491 #  define __hidden_proto(name, internal, attrs...) \
 492   extern __typeof (name) name __asm__ (__hidden_asmname (#internal)) \
 493   __hidden_proto_hiddenattr (attrs);
 494 #  define __hidden_asmname(name) \
 495   __hidden_asmname1 (__USER_LABEL_PREFIX__, name)
 496 #  define __hidden_asmname1(prefix, name) __hidden_asmname2(prefix, name)
 497 #  define __hidden_asmname2(prefix, name) #prefix name
 498 #  define __hidden_ver1(local, internal, name) \
 499   extern __typeof (name) __EI_##name __asm__(__hidden_asmname (#internal)); \
 500   extern __typeof (name) __EI_##name \
 501         __attribute__((alias (__hidden_asmname (#local))))
 502 #  define hidden_ver(local, name)       __hidden_ver1(local, __GI_##name, name);
 503 #  define hidden_data_ver(local, name)  hidden_ver(local, name)
 504 #  define hidden_def(name)              __hidden_ver1(__GI_##name, name, name);
 505 #  define hidden_data_def(name)         hidden_def(name)
 506 #  define hidden_weak(name) \
 507         __hidden_ver1(__GI_##name, name, name) __attribute__((weak));
 508 #  define hidden_data_weak(name)        hidden_weak(name)
 509 #  define hidden_nolink(name, lib, version) \
 510   __hidden_nolink1 (__GI_##name, __EI_##name, name, VERSION_##lib##_##version)
 511 #  define __hidden_nolink1(local, internal, name, version) \
 512   __hidden_nolink2 (local, internal, name, version)
 513 #  define __hidden_nolink2(local, internal, name, version) \
 514   extern __typeof (name) internal __attribute__ ((alias (#local))); \
 515   __hidden_nolink3 (local, internal, #name "@" #version)
 516 #  define __hidden_nolink3(local, internal, vername) \
 517   __asm__ (".symver " #internal ", " vername);
 518 # else
 519 /* For assembly, we need to do the opposite of what we do in C:
 520    in assembly gcc __REDIRECT stuff is not in place, so functions
 521    are defined by its normal name and we need to create the
 522    __GI_* alias to it, in C __REDIRECT causes the function definition
 523    to use __GI_* name and we need to add alias to the real name.
 524    There is no reason to use hidden_weak over hidden_def in assembly,
 525    but we provide it for consistency with the C usage.
 526    hidden_proto doesn't make sense for assembly but the equivalent
 527    is to call via the HIDDEN_JUMPTARGET macro instead of JUMPTARGET.  */
 528 #  define hidden_def(name)      strong_alias (name, __GI_##name)
 529 #  define hidden_weak(name)     hidden_def (name)
 530 #  define hidden_ver(local, name) strong_alias (local, __GI_##name)
 531 #  define hidden_data_def(name) strong_data_alias (name, __GI_##name)
 532 #  define hidden_data_weak(name)        hidden_data_def (name)
 533 #  define hidden_data_ver(local, name) strong_data_alias (local, __GI_##name)
 534 #  ifdef HAVE_ASM_GLOBAL_DOT_NAME
 535 #   define HIDDEN_JUMPTARGET(name) .__GI_##name
 536 #  else
 537 #   define HIDDEN_JUMPTARGET(name) __GI_##name
 538 #  endif
 539 # endif
 540 #else
 541 # ifndef __ASSEMBLER__
 542 #  define hidden_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_def(name) hidden_def (name)
 558 # define libc_hidden_weak(name) hidden_weak (name)
 559 # ifdef LINK_OBSOLETE_RPC
 560    /* libc_hidden_nolink_sunrpc should only get used in sunrpc code.  */
 561 #  define libc_hidden_nolink_sunrpc(name, version) hidden_def (name)
 562 # else
 563 #  define libc_hidden_nolink_sunrpc(name, version) hidden_nolink (name, libc, version)
 564 # endif
 565 # define libc_hidden_ver(local, name) hidden_ver (local, name)
 566 # define libc_hidden_data_def(name) hidden_data_def (name)
 567 # define libc_hidden_data_weak(name) hidden_data_weak (name)
 568 # define libc_hidden_data_ver(local, name) hidden_data_ver (local, name)
 569 #else
 570 # define libc_hidden_proto(name, attrs...)
 571 # define libc_hidden_def(name)
 572 # define libc_hidden_weak(name)
 573 # define libc_hidden_ver(local, name)
 574 # define libc_hidden_data_def(name)
 575 # define libc_hidden_data_weak(name)
 576 # define libc_hidden_data_ver(local, name)
 577 #endif
 578
 579 #if defined NOT_IN_libc && defined IS_IN_rtld
 580 # define rtld_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 581 # define rtld_hidden_def(name) hidden_def (name)
 582 # define rtld_hidden_weak(name) hidden_weak (name)
 583 # define rtld_hidden_ver(local, name) hidden_ver (local, name)
 584 # define rtld_hidden_data_def(name) hidden_data_def (name)
 585 # define rtld_hidden_data_weak(name) hidden_data_weak (name)
 586 # define rtld_hidden_data_ver(local, name) hidden_data_ver (local, name)
 587 #else
 588 # define rtld_hidden_proto(name, attrs...)
 589 # define rtld_hidden_def(name)
 590 # define rtld_hidden_weak(name)
 591 # define rtld_hidden_ver(local, name)
 592 # define rtld_hidden_data_def(name)
 593 # define rtld_hidden_data_weak(name)
 594 # define rtld_hidden_data_ver(local, name)
 595 #endif
 596
 597 #if defined NOT_IN_libc && defined IS_IN_libm
 598 # define libm_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 599 # define libm_hidden_def(name) hidden_def (name)
 600 # define libm_hidden_weak(name) hidden_weak (name)
 601 # define libm_hidden_ver(local, name) hidden_ver (local, name)
 602 # define libm_hidden_data_def(name) hidden_data_def (name)
 603 # define libm_hidden_data_weak(name) hidden_data_weak (name)
 604 # define libm_hidden_data_ver(local, name) hidden_data_ver (local, name)
 605 #else
 606 # define libm_hidden_proto(name, attrs...)
 607 # define libm_hidden_def(name)
 608 # define libm_hidden_weak(name)
 609 # define libm_hidden_ver(local, name)
 610 # define libm_hidden_data_def(name)
 611 # define libm_hidden_data_weak(name)
 612 # define libm_hidden_data_ver(local, name)
 613 #endif
 614
 615 #if defined NOT_IN_libc && defined IS_IN_libresolv
 616 # define libresolv_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 617 # define libresolv_hidden_def(name) hidden_def (name)
 618 # define libresolv_hidden_weak(name) hidden_weak (name)
 619 # define libresolv_hidden_ver(local, name) hidden_ver (local, name)
 620 # define libresolv_hidden_data_def(name) hidden_data_def (name)
 621 # define libresolv_hidden_data_weak(name) hidden_data_weak (name)
 622 # define libresolv_hidden_data_ver(local, name) hidden_data_ver (local, name)
 623 #else
 624 # define libresolv_hidden_proto(name, attrs...)
 625 # define libresolv_hidden_def(name)
 626 # define libresolv_hidden_weak(name)
 627 # define libresolv_hidden_ver(local, name)
 628 # define libresolv_hidden_data_def(name)
 629 # define libresolv_hidden_data_weak(name)
 630 # define libresolv_hidden_data_ver(local, name)
 631 #endif
 632
 633 #if defined NOT_IN_libc && defined IS_IN_librt
 634 # define librt_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 635 # define librt_hidden_def(name) hidden_def (name)
 636 # define librt_hidden_weak(name) hidden_weak (name)
 637 # define librt_hidden_ver(local, name) hidden_ver (local, name)
 638 # define librt_hidden_data_def(name) hidden_data_def (name)
 639 # define librt_hidden_data_weak(name) hidden_data_weak (name)
 640 # define librt_hidden_data_ver(local, name) hidden_data_ver (local, name)
 641 #else
 642 # define librt_hidden_proto(name, attrs...)
 643 # define librt_hidden_def(name)
 644 # define librt_hidden_weak(name)
 645 # define librt_hidden_ver(local, name)
 646 # define librt_hidden_data_def(name)
 647 # define librt_hidden_data_weak(name)
 648 # define librt_hidden_data_ver(local, name)
 649 #endif
 650
 651 #if defined NOT_IN_libc && defined IS_IN_libdl
 652 # define libdl_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 653 # define libdl_hidden_def(name) hidden_def (name)
 654 # define libdl_hidden_weak(name) hidden_weak (name)
 655 # define libdl_hidden_ver(local, name) hidden_ver (local, name)
 656 # define libdl_hidden_data_def(name) hidden_data_def (name)
 657 # define libdl_hidden_data_weak(name) hidden_data_weak (name)
 658 # define libdl_hidden_data_ver(local, name) hidden_data_ver (local, name)
 659 #else
 660 # define libdl_hidden_proto(name, attrs...)
 661 # define libdl_hidden_def(name)
 662 # define libdl_hidden_weak(name)
 663 # define libdl_hidden_ver(local, name)
 664 # define libdl_hidden_data_def(name)
 665 # define libdl_hidden_data_weak(name)
 666 # define libdl_hidden_data_ver(local, name)
 667 #endif
 668
 669 #if defined NOT_IN_libc && defined IS_IN_libnss_files
 670 # define libnss_files_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 671 # define libnss_files_hidden_def(name) hidden_def (name)
 672 # define libnss_files_hidden_weak(name) hidden_weak (name)
 673 # define libnss_files_hidden_ver(local, name) hidden_ver (local, name)
 674 # define libnss_files_hidden_data_def(name) hidden_data_def (name)
 675 # define libnss_files_hidden_data_weak(name) hidden_data_weak (name)
 676 # define libnss_files_hidden_data_ver(local, name) hidden_data_ver(local, name)
 677 #else
 678 # define libnss_files_hidden_proto(name, attrs...)
 679 # define libnss_files_hidden_def(name)
 680 # define libnss_files_hidden_weak(name)
 681 # define libnss_files_hidden_ver(local, name)
 682 # define libnss_files_hidden_data_def(name)
 683 # define libnss_files_hidden_data_weak(name)
 684 # define libnss_files_hidden_data_ver(local, name)
 685 #endif
 686
 687 #if defined NOT_IN_libc && defined IS_IN_libnsl
 688 # define libnsl_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 689 # define libnsl_hidden_def(name) hidden_def (name)
 690 # define libnsl_hidden_weak(name) hidden_weak (name)
 691 # define libnsl_hidden_ver(local, name) hidden_ver (local, name)
 692 # define libnsl_hidden_data_def(name) hidden_data_def (name)
 693 # define libnsl_hidden_data_weak(name) hidden_data_weak (name)
 694 # define libnsl_hidden_data_ver(local, name) hidden_data_ver (local, name)
 695 #else
 696 # define libnsl_hidden_proto(name, attrs...)
 697 # define libnsl_hidden_def(name)
 698 # define libnsl_hidden_weak(name)
 699 # define libnsl_hidden_ver(local, name)
 700 # define libnsl_hidden_data_def(name)
 701 # define libnsl_hidden_data_weak(name)
 702 # define libnsl_hidden_data_ver(local, name)
 703 #endif
 704
 705 #if defined NOT_IN_libc && defined IS_IN_libnss_nisplus
 706 # define libnss_nisplus_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 707 # define libnss_nisplus_hidden_def(name) hidden_def (name)
 708 # define libnss_nisplus_hidden_weak(name) hidden_weak (name)
 709 # define libnss_nisplus_hidden_ver(local, name) hidden_ver (local, name)
 710 # define libnss_nisplus_hidden_data_def(name) hidden_data_def (name)
 711 # define libnss_nisplus_hidden_data_weak(name) hidden_data_weak (name)
 712 # define libnss_nisplus_hidden_data_ver(local, name) hidden_data_ver (local, name)
 713 #else
 714 # define libnss_nisplus_hidden_proto(name, attrs...)
 715 # define libnss_nisplus_hidden_def(name)
 716 # define libnss_nisplus_hidden_weak(name)
 717 # define libnss_nisplus_hidden_ver(local, name)
 718 # define libnss_nisplus_hidden_data_def(name)
 719 # define libnss_nisplus_hidden_data_weak(name)
 720 # define libnss_nisplus_hidden_data_ver(local, name)
 721 #endif
 722
 723 #define libc_hidden_builtin_proto(name, attrs...) libc_hidden_proto (name, ##attrs)
 724 #define libc_hidden_builtin_def(name) libc_hidden_def (name)
 725 #define libc_hidden_builtin_weak(name) libc_hidden_weak (name)
 726 #define libc_hidden_builtin_ver(local, name) libc_hidden_ver (local, name)
 727 #ifdef __ASSEMBLER__
 728 # define HIDDEN_BUILTIN_JUMPTARGET(name) HIDDEN_JUMPTARGET(name)
 729 #endif
 730
 731 #if defined NOT_IN_libc && defined IS_IN_libutil
 732 # define libutil_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
 733 # define libutil_hidden_def(name) hidden_def (name)
 734 # define libutil_hidden_weak(name) hidden_weak (name)
 735 # define libutil_hidden_ver(local, name) hidden_ver (local, name)
 736 # define libutil_hidden_data_def(name) hidden_data_def (name)
 737 # define libutil_hidden_data_weak(name) hidden_data_weak (name)
 738 # define libutil_hidden_data_ver(local, name) hidden_data_ver (local, name)
 739 #else
 740 # define libutil_hidden_proto(name, attrs...)
 741 # define libutil_hidden_def(name)
 742 # define libutil_hidden_weak(name)
 743 # define libutil_hidden_ver(local, name)
 744 # define libutil_hidden_data_def(name)
 745 # define libutil_hidden_data_weak(name)
 746 # define libutil_hidden_data_ver(local, name)
 747 #endif
 748
 749 /* Get some dirty hacks.  */
 750 #include <symbol-hacks.h>
 751
 752 /* Move compatibility symbols out of the way by placing them all in a
 753    special section.  */
 754 #ifndef __ASSEMBLER__
 755 # define attribute_compat_text_section \
 756     __attribute__ ((section (".text.compat")))
 757 # define attribute_compat_data_section \
 758     __attribute__ ((section (".data.compat")))
 759 #else
 760 # define compat_text_section .section ".text.compat", "ax";
 761 # define compat_data_section .section ".data.compat", "aw";
 762 #endif
 763
 764 /* Marker used for indirection function symbols.  */
 765 #define libc_ifunc(name, expr)                                          \
 766   extern void *name##_ifunc (void) __asm__ (#name);                     \
 767   void *name##_ifunc (void)                                             \
 768   {                                                                     \
 769     INIT_ARCH ();                                                       \
 770     __typeof (name) *res = expr;                                        \
 771     return res;                                                         \
 772   }                                                                     \
 773   __asm__ (".type " #name ", %gnu_indirect_function");
 774
 775 /* The body of the function is supposed to use __get_cpu_features
 776    which will, if necessary, initialize the data first.  */
 777 #define libm_ifunc(name, expr)                                          \
 778   extern void *name##_ifunc (void) __asm__ (#name);                     \
 779   void *name##_ifunc (void)                                             \
 780   {                                                                     \
 781     __typeof (name) *res = expr;                                        \
 782     return res;                                                         \
 783   }                                                                     \
 784   __asm__ (".type " #name ", %gnu_indirect_function");
 785
 786 #ifdef HAVE_ASM_SET_DIRECTIVE
 787 # define libc_ifunc_hidden_def1(local, name)                            \
 788     __asm__ (declare_symbol_alias_1_stringify (ASM_GLOBAL_DIRECTIVE)    \
 789              " " #local "\n\t"                                          \
 790              ".hidden " #local "\n\t"                                   \
 791              ".set " #local ", " #name);
 792 #else
 793 # define libc_ifunc_hidden_def1(local, name)                            \
 794     __asm__ (declare_symbol_alias_1_stringify (ASM_GLOBAL_DIRECTIVE)    \
 795              " " #local "\n\t"                                          \
 796              ".hidden " #local "\n\t"                                   \
 797              #local " = " #name);
 798 #endif
 799
 800 #define libc_ifunc_hidden_def(name) \
 801   libc_ifunc_hidden_def1 (__GI_##name, name)
 802
 803 #endif /* libc-symbols.h */