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Use __sync_add_and_fetch and __sync_sub_and_fetch when they are available

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These functions may be available as inlines or as libgcc functions. In the
former case, a __GCC_HAVE_SYNC_COMPARE_AND_SWAP_n macro is defined. But we
still want to use these functions in the latter case, when we don't have
our own implementation.
This commit is contained in:
Mike Hommey 2012-03-26 17:03:41 +02:00 committed by Jason Evans
parent 1e6138c88c
commit c1e567bda0
3 changed files with 65 additions and 3 deletions
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34
configure.ac
View File

@ -886,6 +886,40 @@ if test "x${je_cv_osatomic}" = "xyes" ; then
AC_DEFINE([JEMALLOC_OSATOMIC], [ ])
fi
dnl ============================================================================
dnl Check whether __sync_{add,sub}_and_fetch() are available despite
dnl __GCC_HAVE_SYNC_COMPARE_AND_SWAP_n macros being undefined.
AC_DEFUN([JE_SYNC_COMPARE_AND_SWAP_CHECK],[
AC_CACHE_CHECK([whether to force $1-bit __sync_{add,sub}_and_fetch()],
[je_cv_sync_compare_and_swap_$2],
[AC_COMPILE_IFELSE([AC_LANG_PROGRAM([
#include <stdint.h>
],
[
#ifndef __GCC_HAVE_SYNC_COMPARE_AND_SWAP_$2
{
uint$1_t x$1 = 0;
__sync_add_and_fetch(&x$1, 42);
__sync_sub_and_fetch(&x$1, 1);
}
#else
#error __GCC_HAVE_SYNC_COMPARE_AND_SWAP_$2 is defined, no need to force
#endif
])],
[je_cv_sync_compare_and_swap_$2=yes],
[je_cv_sync_compare_and_swap_$2=no])])
if test "x${je_cv_sync_compare_and_swap_$2}" = "xyes" ; then
AC_DEFINE([JE_FORCE_SYNC_COMPARE_AND_SWAP_$2], [ ])
fi
])
if test "x${je_cv_osatomic}" != "xyes" ; then
JE_SYNC_COMPARE_AND_SWAP_CHECK(32, 4)
JE_SYNC_COMPARE_AND_SWAP_CHECK(64, 8)
fi
dnl ============================================================================
dnl Check for spinlock(3) operations as provided on Darwin.

18
include/jemalloc/internal/atomic.h
View File

@ -87,6 +87,20 @@ atomic_sub_uint64(uint64_t *p, uint64_t x)
return (x);
}
#elif (defined(JE_FORCE_SYNC_COMPARE_AND_SWAP_8))
JEMALLOC_INLINE uint64_t
atomic_add_uint64(uint64_t *p, uint64_t x)
{
return (__sync_add_and_fetch(p, x));
}
JEMALLOC_INLINE uint64_t
atomic_sub_uint64(uint64_t *p, uint64_t x)
{
return (__sync_sub_and_fetch(p, x));
}
#else
# if (LG_SIZEOF_PTR == 3)
# error "Missing implementation for 64-bit atomic operations"
@ -150,9 +164,7 @@ atomic_sub_uint32(uint32_t *p, uint32_t x)
return (x);
}
#elif (defined __SH4__ || defined __mips__) && (__GNUC__ > 4 || \
(__GNUC__ == 4 && (__GNUC_MINOR__ > 1 || (__GNUC_MINOR__ == 1 && \
__GNUC_PATCHLEVEL__ > 1))))
#elif (defined(JE_FORCE_SYNC_COMPARE_AND_SWAP_4))
JEMALLOC_INLINE uint32_t
atomic_add_uint32(uint32_t *p, uint32_t x)
{

16
include/jemalloc/jemalloc_defs.h.in
View File

@ -53,6 +53,22 @@
*/
#undef JEMALLOC_OSATOMIC
/*
* Defined if __sync_add_and_fetch(uint32_t *, uint32_t) and
* __sync_sub_and_fetch(uint32_t *, uint32_t) are available, despite
* __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4 not being defined (which means the
* functions are defined in libgcc instead of being inlines)
*/
#undef JE_FORCE_SYNC_COMPARE_AND_SWAP_4
/*
* Defined if __sync_add_and_fetch(uint64_t *, uint64_t) and
* __sync_sub_and_fetch(uint64_t *, uint64_t) are available, despite
* __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8 not being defined (which means the
* functions are defined in libgcc instead of being inlines)
*/
#undef JE_FORCE_SYNC_COMPARE_AND_SWAP_8
/*
* Defined if OSSpin*() functions are available, as provided by Darwin, and
* documented in the spinlock(3) manual page.