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glibc/sysdeps/generic/libc-symver.h

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Change how the symbol_version_reference macro is defined A subsequent change will require including <config.h> for defining symbol_version_reference. <libc-symbol.h> should not include <config.h> for _ISOMAC, so it cannot define symbol_version_reference anymore, but symbol_version_reference is needed <shlib-compat.h> even for _ISOMAC. Moving the definition of symbol_version_reference to a separate file <libc-symver.h> makes it possible to use a single definition for both cases. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2021-03-25 10:05:37 +00:00
/* Symbol version management.
Update copyright dates with scripts/update-copyrights I used these shell commands: ../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright (cd ../glibc && git commit -am"[this commit message]") and then ignored the output, which consisted lines saying "FOO: warning: copyright statement not found" for each of 7061 files FOO. I then removed trailing white space from math/tgmath.h, support/tst-support-open-dev-null-range.c, and sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following obscure pre-commit check failure diagnostics from Savannah. I don't know why I run into these diagnostics whereas others evidently do not. remote: *** 912-#endif remote: *** 913: remote: *** 914- remote: *** error: lines with trailing whitespace found ... remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
2022-01-01 18:54:23 +00:00
Copyright (C) 1995-2022 Free Software Foundation, Inc.
Change how the symbol_version_reference macro is defined A subsequent change will require including <config.h> for defining symbol_version_reference. <libc-symbol.h> should not include <config.h> for _ISOMAC, so it cannot define symbol_version_reference anymore, but symbol_version_reference is needed <shlib-compat.h> even for _ISOMAC. Moving the definition of symbol_version_reference to a separate file <libc-symver.h> makes it possible to use a single definition for both cases. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2021-03-25 10:05:37 +00:00
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
Support for multiple versions in versioned_symbol, compat_symbol This essentially folds compat_symbol_unique functionality into compat_symbol. This change eliminates the need for intermediate aliases for defining multiple symbol versions, for both compat_symbol and versioned_symbol. Some binutils versions do not suport multiple versions per symbol on some targets, so aliases are automatically introduced, similar to what compat_symbol_unique did. To reduce symbol table sizes, a configure check is added to avoid these aliases if they are not needed. The new mechanism works with data symbols as well as function symbols, due to the way an assembler-level redirect is used. It is not compatible with weak symbols for old binutils versions, which is why the definition of __malloc_initialize_hook had to be changed. This is not a loss of functionality because weak symbols do not matter to dynamic linking. The placeholder symbol needs repeating in nptl/libpthread-compat.c now that compat_symbol is used, but that seems more obvious than introducing yet another macro. A subtle difference was that compat_symbol_unique made the symbol global automatically. compat_symbol does not do this, so static had to be removed from the definition of __libpthread_version_placeholder. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2021-03-25 10:05:37 +00:00
#include <config.h>
Change how the symbol_version_reference macro is defined A subsequent change will require including <config.h> for defining symbol_version_reference. <libc-symbol.h> should not include <config.h> for _ISOMAC, so it cannot define symbol_version_reference anymore, but symbol_version_reference is needed <shlib-compat.h> even for _ISOMAC. Moving the definition of symbol_version_reference to a separate file <libc-symver.h> makes it possible to use a single definition for both cases. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2021-03-25 10:05:37 +00:00
/* 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
Support for multiple versions in versioned_symbol, compat_symbol This essentially folds compat_symbol_unique functionality into compat_symbol. This change eliminates the need for intermediate aliases for defining multiple symbol versions, for both compat_symbol and versioned_symbol. Some binutils versions do not suport multiple versions per symbol on some targets, so aliases are automatically introduced, similar to what compat_symbol_unique did. To reduce symbol table sizes, a configure check is added to avoid these aliases if they are not needed. The new mechanism works with data symbols as well as function symbols, due to the way an assembler-level redirect is used. It is not compatible with weak symbols for old binutils versions, which is why the definition of __malloc_initialize_hook had to be changed. This is not a loss of functionality because weak symbols do not matter to dynamic linking. The placeholder symbol needs repeating in nptl/libpthread-compat.c now that compat_symbol is used, but that seems more obvious than introducing yet another macro. A subtle difference was that compat_symbol_unique made the symbol global automatically. compat_symbol does not do this, so static had to be removed from the definition of __libpthread_version_placeholder. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2021-03-25 10:05:37 +00:00
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. */
Change how the symbol_version_reference macro is defined A subsequent change will require including <config.h> for defining symbol_version_reference. <libc-symbol.h> should not include <config.h> for _ISOMAC, so it cannot define symbol_version_reference anymore, but symbol_version_reference is needed <shlib-compat.h> even for _ISOMAC. Moving the definition of symbol_version_reference to a separate file <libc-symver.h> makes it possible to use a single definition for both cases. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2021-03-25 10:05:37 +00:00
#ifdef __ASSEMBLER__
# define symbol_version_reference(real, name, version) \
.symver real, name##@##version
Support for multiple versions in versioned_symbol, compat_symbol This essentially folds compat_symbol_unique functionality into compat_symbol. This change eliminates the need for intermediate aliases for defining multiple symbol versions, for both compat_symbol and versioned_symbol. Some binutils versions do not suport multiple versions per symbol on some targets, so aliases are automatically introduced, similar to what compat_symbol_unique did. To reduce symbol table sizes, a configure check is added to avoid these aliases if they are not needed. The new mechanism works with data symbols as well as function symbols, due to the way an assembler-level redirect is used. It is not compatible with weak symbols for old binutils versions, which is why the definition of __malloc_initialize_hook had to be changed. This is not a loss of functionality because weak symbols do not matter to dynamic linking. The placeholder symbol needs repeating in nptl/libpthread-compat.c now that compat_symbol is used, but that seems more obvious than introducing yet another macro. A subtle difference was that compat_symbol_unique made the symbol global automatically. compat_symbol does not do this, so static had to be removed from the definition of __libpthread_version_placeholder. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2021-03-25 10:05:37 +00:00
#else
Change how the symbol_version_reference macro is defined A subsequent change will require including <config.h> for defining symbol_version_reference. <libc-symbol.h> should not include <config.h> for _ISOMAC, so it cannot define symbol_version_reference anymore, but symbol_version_reference is needed <shlib-compat.h> even for _ISOMAC. Moving the definition of symbol_version_reference to a separate file <libc-symver.h> makes it possible to use a single definition for both cases. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2021-03-25 10:05:37 +00:00
# define symbol_version_reference(real, name, version) \
__asm__ (".symver " #real "," #name "@" #version)
Support for multiple versions in versioned_symbol, compat_symbol This essentially folds compat_symbol_unique functionality into compat_symbol. This change eliminates the need for intermediate aliases for defining multiple symbol versions, for both compat_symbol and versioned_symbol. Some binutils versions do not suport multiple versions per symbol on some targets, so aliases are automatically introduced, similar to what compat_symbol_unique did. To reduce symbol table sizes, a configure check is added to avoid these aliases if they are not needed. The new mechanism works with data symbols as well as function symbols, due to the way an assembler-level redirect is used. It is not compatible with weak symbols for old binutils versions, which is why the definition of __malloc_initialize_hook had to be changed. This is not a loss of functionality because weak symbols do not matter to dynamic linking. The placeholder symbol needs repeating in nptl/libpthread-compat.c now that compat_symbol is used, but that seems more obvious than introducing yet another macro. A subtle difference was that compat_symbol_unique made the symbol global automatically. compat_symbol does not do this, so static had to be removed from the definition of __libpthread_version_placeholder. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2021-03-25 10:05:37 +00:00
#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 */
Change how the symbol_version_reference macro is defined A subsequent change will require including <config.h> for defining symbol_version_reference. <libc-symbol.h> should not include <config.h> for _ISOMAC, so it cannot define symbol_version_reference anymore, but symbol_version_reference is needed <shlib-compat.h> even for _ISOMAC. Moving the definition of symbol_version_reference to a separate file <libc-symver.h> makes it possible to use a single definition for both cases. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2021-03-25 10:05:37 +00:00
#endif /* _LIBC_SYMVER_H */
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