| From df087711cf7be55268a55e7820f4d928cb34c078 Mon Sep 17 00:00:00 2001 |
| From: "Yann E. MORIN" <yann.morin.1998@free.fr> |
| Date: Sat, 9 Jul 2016 20:44:36 +0200 |
| Subject: [PATCH] m4: fix detection of atomics |
| |
| In cross-compilation, it is impossible to run code at configure time to |
| detect the target specifics. |
| |
| As such, AC_TRY_RUN fails miserably to detect reliably that atomic |
| intrisics are present in a toolchain, and decides they are not just |
| because this is cross-compilation. |
| |
| Instead of AC_TRY_RUN, use AC_LINK_IFELSE that does not need to actually |
| run code, since all we're interested in is whether the intrisics are |
| present (or not). Fix both the 32- and 64-bit variants, even if the |
| latter is not used currently. |
| |
| Fixes build failures detected by the Buildroot autobuilders, like: |
| http://autobuild.buildroot.org/results/23a/23ac0e742ed3a70ae4d038f8c9eadc23e708f671/build-end.log |
| http://autobuild.buildroot.org/results/192/1923d0b570adba494f83747a9610ea6ec35f5223/build-end.log |
| |
| and many other cases, espcially on architectures where such intrisics are |
| present, but where the toolchain does not have threads (and anyway, it |
| is much more efficient to use the intrisics rather than use mutexes). |
| |
| Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr> |
| --- |
| Patch sent upstream: |
| https://github.com/rsyslog/libfastjson/pull/109 |
| |
| --- |
| m4/atomic_operations.m4 | 6 ++---- |
| m4/atomic_operations_64bit.m4 | 6 ++---- |
| 2 files changed, 4 insertions(+), 8 deletions(-) |
| |
| diff --git a/m4/atomic_operations.m4 b/m4/atomic_operations.m4 |
| index ad0ee60..7d2bca6 100644 |
| --- a/m4/atomic_operations.m4 |
| +++ b/m4/atomic_operations.m4 |
| @@ -9,9 +9,7 @@ |
| # |
| AC_DEFUN([RS_ATOMIC_OPERATIONS], |
| [AC_CACHE_CHECK([whether the compiler provides atomic builtins], [ap_cv_atomic_builtins], |
| -[AC_TRY_RUN([ |
| -int main() |
| -{ |
| +[AC_LINK_IFELSE([AC_LANG_PROGRAM([], [[ |
| unsigned long val = 1010, tmp, *mem = &val; |
| |
| if (__sync_fetch_and_add(&val, 1010) != 1010 || val != 2020) |
| @@ -44,7 +42,7 @@ int main() |
| return 1; |
| |
| return 0; |
| -}], [ap_cv_atomic_builtins=yes], [ap_cv_atomic_builtins=no], [ap_cv_atomic_builtins=no])]) |
| +]])], [ap_cv_atomic_builtins=yes], [ap_cv_atomic_builtins=no])]) |
| |
| if test "$ap_cv_atomic_builtins" = "yes"; then |
| AC_DEFINE(HAVE_ATOMIC_BUILTINS, 1, [Define if compiler provides atomic builtins]) |
| diff --git a/m4/atomic_operations_64bit.m4 b/m4/atomic_operations_64bit.m4 |
| index 9fbef0a..d01a977 100644 |
| --- a/m4/atomic_operations_64bit.m4 |
| +++ b/m4/atomic_operations_64bit.m4 |
| @@ -9,9 +9,7 @@ |
| # |
| AC_DEFUN([RS_ATOMIC_OPERATIONS_64BIT], |
| [AC_CACHE_CHECK([whether the compiler provides atomic builtins for 64 bit data types], [ap_cv_atomic_builtins_64], |
| -[AC_TRY_RUN([ |
| -int main() |
| -{ |
| +[AC_LINK_IFELSE([AC_LANG_PROGRAM([], [[ |
| unsigned long long val = 1010, tmp, *mem = &val; |
| |
| if (__sync_fetch_and_add(&val, 1010) != 1010 || val != 2020) |
| @@ -44,7 +42,7 @@ int main() |
| return 1; |
| |
| return 0; |
| -}], [ap_cv_atomic_builtins_64=yes], [ap_cv_atomic_builtins_64=no], [ap_cv_atomic_builtins_64=no])]) |
| +]])], [ap_cv_atomic_builtins_64=yes], [ap_cv_atomic_builtins_64=no])]) |
| |
| if test "$ap_cv_atomic_builtins_64" = "yes"; then |
| AC_DEFINE(HAVE_ATOMIC_BUILTINS64, 1, [Define if compiler provides 64 bit atomic builtins]) |
| -- |
| 2.7.4 |
| |