glibc/sysdeps/generic/libc-symver.h

89 lines
3.6 KiB
C

/* Symbol version management.
Copyright (C) 1995-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
/* This file is included from <libc-symbols.h> for !_ISOMAC, and
unconditionally from <shlib-compat.h>. */
#ifndef _LIBC_SYMVER_H
#define _LIBC_SYMVER_H 1
#include <config.h>
/* Use symbol_version_reference to specify the version a symbol
reference should link to. Use symbol_version or
default_symbol_version for the definition of a versioned symbol.
The difference is that the latter is a no-op in non-shared
builds.
_set_symbol_version is similar to symbol_version_reference, except
that this macro expects the name and symbol version as a single
string or token sequence, with an @ or @@ separator. (A string is
used in C mode and a token sequence in assembler mode.)
_set_symbol_version only be used for definitions because it may
introduce an alias symbol that would not be globally unique for
mere references. The _set_symbol_version macro is used to define
default_symbol_version and compat_symbol. */
#ifdef __ASSEMBLER__
# define symbol_version_reference(real, name, version) \
.symver real, name##@##version
#else
# define symbol_version_reference(real, name, version) \
__asm__ (".symver " #real "," #name "@" #version)
#endif /* !__ASSEMBLER__ */
#if SYMVER_NEEDS_ALIAS
/* If the assembler cannot support multiple versions for the same
symbol, introduce __SInnn_ aliases to which the symbol version is
attached. */
# define __symbol_version_unique_concat(x, y) __SI ## x ## _ ## y
# define _symbol_version_unique_concat(x, y) \
__symbol_version_unique_concat (x, y)
# define _symbol_version_unique_alias(name) \
_symbol_version_unique_concat (name, __COUNTER__)
# ifdef __ASSEMBLER__
# define _set_symbol_version_2(real, alias, name_version) \
.globl alias ASM_LINE_SEP \
.equiv alias, real ASM_LINE_SEP \
.symver alias, name_version
# else
# define _set_symbol_version_2(real, alias, name_version) \
__asm__ (".globl " #alias "\n\t" \
".equiv " #alias ", " #real "\n\t" \
".symver " #alias "," name_version)
# endif
# define _set_symbol_version_1(real, alias, name_version) \
_set_symbol_version_2 (real, alias, name_version)
/* REAL must be globally unique, so that the counter also produces
globally unique symbols. */
# define _set_symbol_version(real, name_version) \
_set_symbol_version_1 (real, _symbol_version_unique_alias (real), \
name_version)
# else /* !SYMVER_NEEDS_ALIAS */
# ifdef __ASSEMBLER__
# define _set_symbol_version(real, name_version) \
.symver real, name_version
# else
# define _set_symbol_version(real, name_version) \
__asm__ (".symver " #real "," name_version)
# endif
#endif /* !SYMVER_NEEDS_ALIAS */
#endif /* _LIBC_SYMVER_H */