attribute: new module

This simplifies use of GCC and C2X attributes like ‘deprecated’.
* MODULES.html.sh: Add attribute.
* doc/attribute.texi, lib/attribute.h, modules/attribute: New files.
* doc/gnulib.texi (Particular Modules): Add Attributes.
* lib/backupfile.c, lib/fnmatch.c, lib/freopen-safer.c:
* lib/mbrtoc32.c, lib/mbrtowc.c, lib/nstrftime.c, lib/quotearg.c:
* lib/savewd.c, lib/unistr/u8-uctomb-aux.c, lib/unistr/u8-uctomb.c:
* lib/vasnprintf.c:
Include attribute.h, and let it define FALLTHROUGH.
* lib/bitset/base.h, lib/c-stack.c (__attribute__): Remove macro.
* lib/bitset/base.h (ATTRIBUTE_UNUSED): Define in terms of
_GL_ATTRIBUTE_MAYBE_UNUSED, for forwards compatibility to C2X.
* lib/dfa.c (FALLTHROUGH): Define consistently with gl_COMMON_BODY.
This is a copy since Gawk doesn’t use Gnulib.
* lib/di-set.h (_GL_ATTRIBUTE_NONNULL): Remove definition that
is incompatible with gl_COMMON_BODY’s.  All uses changed.
* lib/fts.c: Include attribte.h, for FALLTHROUGH.
Keep the existing FALLTHROUGH definition since Glibc might use it,
and it does no harm to Gnulib’s FALLTHROUGH.
* lib/fts_.h, lib/inttostr.h:
(__GNUC_PREREQ): Remove; no longer needed.
(__attribute_warn_unused_result__): Remove.  All uses
replaced by _GL_ATTRIBUTE_NODISCARD.
* lib/gl_list.h, lib/gl_map.h, lib/gl_omap.h, lib/gl_oset.h:
* lib/gl_set.h: Prefer _GL_ATTRIBUTE_NODISCARD to an ifdeffed
__attribute__ ((__warn_unused_result__)), for forward
compatibility to C2X.
* lib/hash.h (_GL_ATTRIBUTE_WUR): Remove.  All uses replaced by
_GL_ATTRIBUTE_NODISCARD.
(_GL_ATTRIBUTE_DEPRECATED): Remove, since gl_COMMON_BODY defines it.
* lib/ino-map.h (_GL_ATTRIBUTE_NONNULL): Remove.  All uses
replaced by gl_COMMON_BODY’s implementation, which has a
slightly different signature.
* lib/safe-alloc.h (_GL_ATTRIBUTE_RETURN_CHECK):
Remove.  All uses replaced by _GL_ATTRIBUTE_NODISCARD.
* lib/unused-parameter.h (_GL_UNUSED_PARAMETER):
Define in terms of _GL_ATTRIBUTE_MAYBE_UNUSED.
No doubt all uses should be replaced, at some point.
* m4/gnulib-common.m4 (_GL_GNUC_PREREQ): New macro.
(_Noreturn): Use it.
(_GL_HAS_ATTRIBUTE, _GL_ATTRIBUTE_ALLOC_SIZE)
(_GL_ATTRIBUTE_ALWAYS_INLINE, _GL_ATTRIBUTE_ARTIFICIAL)
(_GL_ATTRIBUTE_COLD)
(_GL_ATTRIBUTE_DEPRECATED, _GL_ATTRIBUTE_ERROR)
(_GL_ATTRIBUTE_WARNING, _GL_ATTRIBUTE_EXTERNALLY_VISIBLE)
(_GL_ATTRIBUTE_FALLTHROUGH, _GL_ATTRIBUTE_FORMAT)
(_GL_ATTRIBUTE_LEAF, _GL_ATTRIBUTE_MAY_ALIAS)
(_GL_ATTRIBUTE_MAYBE_UNUSED)
(_GL_ATTRIBUTE_NODISCARD, _GL_ATTRIBUTE_NOINLINE)
(_GL_ATTRIBUTE_NONNULL, _GL_ATTRIBUTE_NONSTRING)
(_GL_ATTRIBUTE_NOTHROW, _GL_ATTRIBUTE_PACKED, _GL_ATTRIBUTE_PURE)
(_GL_ATTRIBUTE_SENTINEL): New macros.
* modules/backup-rename, modules/backupfile, modules/c-vasnprintf:
* modules/fnmatch, modules/freopen-safer, modules/fts:
* modules/mbrtoc32, modules/mbrtowc, modules/nstrftime:
* modules/quotearg, modules/savewd:
* modules/unistdio/u16-u16-vasnprintf:
* modules/unistdio/u16-vasnprintf:
* modules/unistdio/u32-u32-vasnprintf:
* modules/unistdio/u32-vasnprintf:
* modules/unistdio/u8-u8-vasnprintf:
* modules/unistdio/u8-vasnprintf:
* modules/unistdio/ulc-vasnprintf:
* modules/unistr/u8-uctomb, modules/vasnprintf:
(Depends-on:): Add attribute module.

1 files changed, 56 insertions, 0 deletions

diff --git a/lib/attribute.h b/lib/attribute.h
new file mode 100644
index 0000000000..ffd9bdfa28
--- /dev/null
+++ b/lib/attribute.h
@@ -0,0 +1,56 @@
+/* ATTRIBUTE_* macros for using attributes in GCC and similar compilers
+
+   Copyright 2020 Free Software Foundation, Inc.
+
+   This program 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 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Paul Eggert.  */
+
+/* Provide public ATTRIBUTE_* names for the private _GL_ATTRIBUTE_*
+   macros used within Gnulib.  */
+
+#ifndef _GL_ATTRIBUTE_H
+#define _GL_ATTRIBUTE_H
+
+/* C2X standard attributes have macro names that do not begin with
+   'ATTRIBUTE_'.  */
+#define DEPRECATED _GL_ATTRIBUTE_DEPRECATED
+#define FALLTHROUGH _GL_ATTRIBUTE_FALLTHROUGH
+#define MAYBE_UNUSED _GL_ATTRIBUTE_MAYBE_UNUSED
+#define NODISCARD _GL_ATTRIBUTE_NODISCARD
+
+/* Attributes from GCC have macro names beginning with 'ATTRIBUTE_' to
+   avoid name clashes.  */
+#define ATTRIBUTE_ALLOC_SIZE(args) _GL_ATTRIBUTE_ALLOC_SIZE(args)
+#define ATTRIBUTE_ALWAYS_INLINE _GL_ATTRIBUTE_ALWAYS_INLINE
+#define ATTRIBUTE_ARTIFICIAL _GL_ATTRIBUTE_ARTIFICIAL
+#define ATTRIBUTE_COLD _GL_ATTRIBUTE_COLD
+#define ATTRIBUTE_CONST _GL_ATTRIBUTE_CONST
+#define ATTRIBUTE_DEPRECATED _GL_ATTRIBUTE_DEPRECATED
+#define ATTRIBUTE_ERROR(msg) _GL_ATTRIBUTE_ERROR(msg)
+#define ATTRIBUTE_EXTERNALLY_VISIBLE _GL_ATTRIBUTE_EXTERNALLY_VISIBLE
+#define ATTRIBUTE_FORMAT(spec) _GL_ATTRIBUTE_FORMAT(spec)
+#define ATTRIBUTE_LEAF _GL_ATTRIBUTE_LEAF
+#define ATTRIBUTE_MAY_ALIAS _GL_ATTRIBUTE_MAY_ALIAS
+#define ATTRIBUTE_MALLOC _GL_ATTRIBUTE_MALLOC
+#define ATTRIBUTE_NOINLINE _GL_ATTRIBUTE_NOINLINE
+#define ATTRIBUTE_NONNULL(args) _GL_ATTRIBUTE_NONNULL(args)
+#define ATTRIBUTE_NONSTRING _GL_ATTRIBUTE_NONSTRING
+#define ATTRIBUTE_NOTHROW _GL_ATTRIBUTE_NOTHROW
+#define ATTRIBUTE_PACKED _GL_ATTRIBUTE_PACKED
+#define ATTRIBUTE_PURE _GL_ATTRIBUTE_PURE
+#define ATTRIBUTE_SENTINEL(pos) _GL_ATTRIBUTE_SENTINEL(pos)
+#define ATTRIBUTE_WARNING(msg) _GL_ATTRIBUTE_WARNING(msg)
+
+#endif /* _GL_ATTRIBUTE_H */