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6b7067460f
Clang issues a warning for double alias redirection, indicating that thei
original symbol is used even if a weak definition attempts to override it.
For instance, in the construction:
int __internal_impl (...) {}
weak_alias (__internal_impl, external_impl);
#if SOMETHING
weak_alias (external_impl, another_external_impl)
#endif
Clang warns that another_external_impl always resolves to __internal_impl,
even if external_impl is a weak reference. Using the internal symbol for
both aliases resolves this warning.
This issue also occurs with certain libc_hidden_def usage:
int __internal_impl (...) {}
weak_alias (__internal_impl, __internal_alias)
libc_hidden_weak (__internal_alias)
In this case, using a strong_alias is sufficient to avoid the warning
(since the alias is internal, there is no need to use a weak alias).
However, for the constructions like:
int __internal_impl (...) {}
weak_alias (__internal_impl, __internal_alias)
libc_hidden_def (__internal_alias)
weak_alias (__internal_impl, external_alias)
libc_hidden_def (external_alias)
Clang warns that the internal external_alias will always resolve to
__GI___internal_impl, even if a weak definition of __GI_internal_impl is
overridden. For this case, a new macro named static_weak_alias is used
to create a strong alias for SHARED, or a weak_alias otherwise.
With these changes, there is no need to check and enable the
-Wno-ignored-attributes suppression when using clang.
Checked with a build on affected ABIs, and a full check on aarch64,
armhf, i686, and x86_64.
Reviewed-by: Sam James <sam@gentoo.org>
61 lines
1.8 KiB
C
61 lines
1.8 KiB
C
/* Linux lseek implementation, 64 bits off_t.
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Copyright (C) 2016-2025 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library. If not, see
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<https://www.gnu.org/licenses/>. */
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#include <unistd.h>
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#include <stdint.h>
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#include <sys/types.h>
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#include <sysdep.h>
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#include <errno.h>
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#include <shlib-compat.h>
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off64_t
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__lseek64 (int fd, off64_t offset, int whence)
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{
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#ifdef __NR_llseek
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# define __NR__llseek __NR_llseek
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#endif
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#ifdef __NR__llseek
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loff_t res;
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int rc = INLINE_SYSCALL_CALL (_llseek, fd,
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(long) (((uint64_t) (offset)) >> 32),
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(long) offset, &res, whence);
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return rc ?: res;
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#else
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return INLINE_SYSCALL_CALL (lseek, fd, offset, whence);
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#endif
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}
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#ifdef __OFF_T_MATCHES_OFF64_T
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weak_alias (__lseek64, lseek)
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strong_alias (__lseek64, __lseek)
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strong_alias (__lseek64, __libc_lseek)
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libc_hidden_def (__lseek)
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#endif
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strong_alias (__lseek64, __libc_lseek64)
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weak_alias (__lseek64, lseek64)
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#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_28)
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compat_symbol (libc, __lseek64, llseek, GLIBC_2_0);
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#endif
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#if !IS_IN(rtld) && OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_1, GLIBC_2_2)
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compat_symbol (libc, __lseek64, lseek64, GLIBC_2_2);
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#endif
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