glibc/sysdeps/x86_64/multiarch/mempcpy.c
Martin Sebor 1626a1cfcd Add support for GCC 9 attribute copy.
GCC 9 has gained an enhancement to help detect attribute mismatches
between alias declarations and their targets.  It consists of a new
warning, -Wattribute-alias, an enhancement to an existing warning,
-Wmissing-attributes, and a new attribute called copy.

The purpose of the warnings is to help identify either possible bugs
(an alias declared with more restrictive attributes than its target
promises) or optimization or diagnostic opportunities (an alias target
missing some attributes that it could be declared with that might
benefit analysis and code generation).  The purpose of the new
attribute is to easily apply (almost) the same set of attributes
to one declaration as those already present on another.

As expected (and intended) the enhancement triggers warnings for
many alias declarations in Glibc code.  This change, tested on
x86_64-linux, avoids all instances of the new warnings by making
use of the attribute where appropriate.  To fully benefit from
the enhancement Glibc will need to be compiled with
 -Wattribute-alias=2 and remaining warnings reviewed and dealt with
(there are a couple of thousand but most should be straightforward
to deal with).

ChangeLog:

	* include/libc-symbols.h (__attribute_copy__): Define macro unless
	it's already defined.
	(_strong_alias): Use __attribute_copy__.
	(_weak_alias,  __hidden_ver1,  __hidden_nolink2): Same.
	* misc/sys/cdefs.h (__attribute_copy__): New macro.
	* sysdeps/x86_64/multiarch/memchr.c (memchr): Use __attribute_copy__.
	* sysdeps/x86_64/multiarch/memcmp.c (memcmp): Same.
	* sysdeps/x86_64/multiarch/mempcpy.c (mempcpy): Same.
	* sysdeps/x86_64/multiarch/memset.c (memset): Same.
	* sysdeps/x86_64/multiarch/stpcpy.c (stpcpy): Same.
	* sysdeps/x86_64/multiarch/strcat.c (strcat): Same.
	* sysdeps/x86_64/multiarch/strchr.c (strchr): Same.
	* sysdeps/x86_64/multiarch/strcmp.c (strcmp): Same.
	* sysdeps/x86_64/multiarch/strcpy.c (strcpy): Same.
	* sysdeps/x86_64/multiarch/strcspn.c (strcspn): Same.
	* sysdeps/x86_64/multiarch/strlen.c (strlen): Same.
	* sysdeps/x86_64/multiarch/strncmp.c (strncmp): Same.
	* sysdeps/x86_64/multiarch/strncpy.c (strncpy): Same.
	* sysdeps/x86_64/multiarch/strnlen.c (strnlen): Same.
	* sysdeps/x86_64/multiarch/strpbrk.c (strpbrk): Same.
	* sysdeps/x86_64/multiarch/strrchr.c (strrchr): Same.
	* sysdeps/x86_64/multiarch/strspn.c (strspn): Same.
2018-11-09 17:24:12 -07:00

43 lines
1.6 KiB
C

/* Multiple versions of mempcpy.
All versions must be listed in ifunc-impl-list.c.
Copyright (C) 2017-2018 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
<http://www.gnu.org/licenses/>. */
/* Define multiple versions only for the definition in libc. */
#if IS_IN (libc)
# define mempcpy __redirect_mempcpy
# define __mempcpy __redirect___mempcpy
# define NO_MEMPCPY_STPCPY_REDIRECT
# define __NO_STRING_INLINES
# include <string.h>
# undef mempcpy
# undef __mempcpy
# define SYMBOL_NAME mempcpy
# include "ifunc-memmove.h"
libc_ifunc_redirected (__redirect_mempcpy, __mempcpy, IFUNC_SELECTOR ());
weak_alias (__mempcpy, mempcpy)
# ifdef SHARED
__hidden_ver1 (__mempcpy, __GI___mempcpy, __redirect___mempcpy)
__attribute__ ((visibility ("hidden"))) __attribute_copy__ (mempcpy);
__hidden_ver1 (mempcpy, __GI_mempcpy, __redirect_mempcpy)
__attribute__ ((visibility ("hidden"))) __attribute_copy__ (mempcpy);
# endif
#endif