1/* Symbol version management.
 2   Copyright (C) 1995-2025 Free Software Foundation, Inc.
 3   This file is part of the GNU C Library.
 4
 5   The GNU C Library is free software; you can redistribute it and/or
 6   modify it under the terms of the GNU Lesser General Public
 7   License as published by the Free Software Foundation; either
 8   version 2.1 of the License, or (at your option) any later version.
 9
10   The GNU C Library is distributed in the hope that it will be useful,
11   but WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13   Lesser General Public License for more details.
14
15   You should have received a copy of the GNU Lesser General Public
16   License along with the GNU C Library; if not, see
17   <https://www.gnu.org/licenses/>.  */
18
19/* This file is included from <libc-symbols.h> for !_ISOMAC, and
20   unconditionally from <shlib-compat.h>.  */
21
22#ifndef _LIBC_SYMVER_H
23#define _LIBC_SYMVER_H 1
24
25#include <config.h>
26
27/* Use symbol_version_reference to specify the version a symbol
28   reference should link to.  Use symbol_version or
29   default_symbol_version for the definition of a versioned symbol.
30   The difference is that the latter is a no-op in non-shared
31   builds.
32
33   _set_symbol_version is similar to symbol_version_reference, except
34   that this macro expects the name and symbol version as a single
35   string or token sequence, with an @ or @@ separator.  (A string is
36   used in C mode and a token sequence in assembler mode.)
37   _set_symbol_version only be used for definitions because it may
38   introduce an alias symbol that would not be globally unique for
39   mere references.  The _set_symbol_version macro is used to define
40   default_symbol_version and compat_symbol.  */
41
42#ifdef __ASSEMBLER__
43# define symbol_version_reference(real, name, version) \
44     .symver real, name##@##version
45#else
46# define symbol_version_reference(real, name, version) \
47  __asm__ (".symver " #real "," #name "@" #version)
48#endif  /* !__ASSEMBLER__ */
49
50#if SYMVER_NEEDS_ALIAS
51/* If the assembler cannot support multiple versions for the same
52   symbol, introduce __SInnn_ aliases to which the symbol version is
53   attached.  */
54# define __symbol_version_unique_concat(x, y) __SI ## x ## _ ## y
55# define _symbol_version_unique_concat(x, y) \
56  __symbol_version_unique_concat (x, y)
57# define _symbol_version_unique_alias(name) \
58  _symbol_version_unique_concat (name, __COUNTER__)
59# ifdef __ASSEMBLER__
60#  define _set_symbol_version_2(real, alias, name_version) \
61  .globl alias ASM_LINE_SEP                                \
62  .equiv alias, real ASM_LINE_SEP                          \
63  .symver alias, name_version
64# else
65#  define _set_symbol_version_2(real, alias, name_version) \
66  __asm__ (".globl " #alias "\n\t"                         \
67           ".equiv " #alias ", " #real "\n\t"              \
68           ".symver " #alias "," name_version)
69# endif
70# define _set_symbol_version_1(real, alias, name_version) \
71  _set_symbol_version_2 (real, alias, name_version)
72/* REAL must be globally unique, so that the counter also produces
73   globally unique symbols.  */
74# define _set_symbol_version(real, name_version)                   \
75  _set_symbol_version_1 (real, _symbol_version_unique_alias (real), \
76                               name_version)
77# else  /* !SYMVER_NEEDS_ALIAS */
78# ifdef __ASSEMBLER__
79#  define _set_symbol_version(real, name_version) \
80  .symver real, name_version
81# else
82#  define _set_symbol_version(real, name_version) \
83  __asm__ (".symver " #real "," name_version)
84# endif
85#endif  /* !SYMVER_NEEDS_ALIAS */
86
87
88#endif /* _LIBC_SYMVER_H */