mirror of
https://sourceware.org/git/glibc.git
synced 2025-12-21 17:31:10 +03:00
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>
88 lines
3.4 KiB
C
88 lines
3.4 KiB
C
/* Copyright (C) 1993-2025 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/>.
|
|
|
|
As a special exception, if you link the code in this file with
|
|
files compiled with a GNU compiler to produce an executable,
|
|
that does not cause the resulting executable to be covered by
|
|
the GNU Lesser General Public License. This exception does not
|
|
however invalidate any other reasons why the executable file
|
|
might be covered by the GNU Lesser General Public License.
|
|
This exception applies to code released by its copyright holders
|
|
in files containing the exception. */
|
|
|
|
#include "libioP.h"
|
|
|
|
size_t
|
|
_IO_fwrite (const void *buf, size_t size, size_t count, FILE *fp)
|
|
{
|
|
size_t request = size * count;
|
|
size_t written = 0;
|
|
CHECK_FILE (fp, 0);
|
|
if (request == 0)
|
|
return 0;
|
|
_IO_acquire_lock (fp);
|
|
if (_IO_vtable_offset (fp) != 0 || _IO_fwide (fp, -1) == -1)
|
|
{
|
|
/* Compute actually written bytes plus pending buffer
|
|
contents. */
|
|
uint64_t original_total_written
|
|
= fp->_total_written + (fp->_IO_write_ptr - fp->_IO_write_base);
|
|
written = _IO_sputn (fp, (const char *) buf, request);
|
|
if (written == EOF)
|
|
{
|
|
/* An error happened and we need to find the appropriate return
|
|
value. There 3 possible scenarios:
|
|
1. If the number of bytes written is between 0..[buffer content],
|
|
we need to return 0 because none of the bytes from this
|
|
request have been written;
|
|
2. If the number of bytes written is between
|
|
[buffer content]+1..request-1, that means we managed to write
|
|
data requested in this fwrite call;
|
|
3. We might have written all the requested data and got an error
|
|
anyway. We can't return success, which means we still have to
|
|
return less than request. */
|
|
if (fp->_total_written > original_total_written)
|
|
{
|
|
written = fp->_total_written - original_total_written;
|
|
/* If everything was reported as written and somehow an
|
|
error occurred afterwards, avoid reporting success. */
|
|
if (written == request)
|
|
--written;
|
|
}
|
|
else
|
|
/* Only already-pending buffer contents was written. */
|
|
written = 0;
|
|
}
|
|
}
|
|
_IO_release_lock (fp);
|
|
/* We have written all of the input in case the return value indicates
|
|
this. */
|
|
if (written == request)
|
|
return count;
|
|
else
|
|
return written / size;
|
|
}
|
|
libc_hidden_def (_IO_fwrite)
|
|
|
|
# include <stdio.h>
|
|
static_weak_alias (_IO_fwrite, fwrite)
|
|
libc_hidden_weak (fwrite)
|
|
# ifndef _IO_MTSAFE_IO
|
|
weak_alias (_IO_fwrite, fwrite_unlocked)
|
|
libc_hidden_weak (fwrite_unlocked)
|
|
# endif
|