Files
glibc/wctype/Makefile
Adhemerval Zanella 6b7067460f Handle clang -Wignored-attributes on weak aliases
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>
2025-12-09 08:58:10 -03:00

32 lines
1.1 KiB
Makefile

# Copyright (C) 1996-2025 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/>.
#
# Sub-makefile for wctype portion of the library.
#
subdir := wctype
include ../Makeconfig
headers := wctype.h bits/wctype-wchar.h
routines := wcfuncs wctype iswctype wctrans towctrans \
wcfuncs_l wctype_l iswctype_l wctrans_l towctrans_l
tests := test_wctype test_wcfuncs bug-wctypeh
include ../Rules