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Use __sync builtin atomics on all architectures if available

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We can use the __sync builtin atomics also on other architectures than
IA64. GCC 4.7 documentation notes that these builtins are ``legacy'' --
adding support for the newer GCC __atomic atomics should be fairly easy.
This commit is contained in:
Tommi Rantala 2012-09-06 15:42:35 +03:00
parent 9a3565ddc1
commit c2d6f85a0a
2 changed files with 20 additions and 6 deletions
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14
configure.ac
View file

@ -283,6 +283,20 @@ if test x$have__builtin___clear_cache = xyes; then
fi
AC_MSG_RESULT([$have__builtin___clear_cache])
AC_MSG_CHECKING([for __sync atomics])
AC_LINK_IFELSE(
[AC_LANG_PROGRAM([[]], [[
__sync_bool_compare_and_swap((int *)0, 0, 1);
__sync_fetch_and_add((int *)0, 1);
]])],
[have_sync_atomics=yes],
[have_sync_atomics=no])
if test x$have_sync_atomics = xyes; then
AC_DEFINE([HAVE_SYNC_ATOMICS], [1],
[Defined if __sync atomics are available])
fi
AC_MSG_RESULT([$have_sync_atomics])
CCASFLAGS="${CCASFLAGS} ${CPPFLAGS}"
arch="$target_arch"

12
include/libunwind_i.h
View file

@ -116,9 +116,10 @@ cmpxchg_ptr (void *addr, void *old, void *new)
# define HAVE_CMPXCHG
# endif
# define HAVE_FETCH_AND_ADD
#else
#elif defined(HAVE_SYNC_ATOMICS) || defined(HAVE_IA64INTRIN_H)
# ifdef HAVE_IA64INTRIN_H
# include <ia64intrin.h>
# endif
static inline int
cmpxchg_ptr (void *addr, void *old, void *new)
{
@ -132,11 +133,10 @@ cmpxchg_ptr (void *addr, void *old, void *new)
u.vp = addr;
return __sync_bool_compare_and_swap(u.vlp, (long) old, (long) new);
}
# define fetch_and_add1(_ptr) __sync_fetch_and_add(_ptr, 1)
# define fetch_and_add(_ptr, value) __sync_fetch_and_add(_ptr, value)
# define HAVE_CMPXCHG
# define HAVE_FETCH_AND_ADD
# endif
# define fetch_and_add1(_ptr) __sync_fetch_and_add(_ptr, 1)
# define fetch_and_add(_ptr, value) __sync_fetch_and_add(_ptr, value)
# define HAVE_CMPXCHG
# define HAVE_FETCH_AND_ADD
#endif
#define atomic_read(ptr) (*(ptr))