Add check for -latomic

Later versions of gcc on some architectures push atomic functions out into a separate atomic library; add a check to see when this is required and add it to LIBS if need be. Specifically the problem was observed on GCC 4.8.2 on powerpc architecture for Ubuntu 14.04: https://launchpadlibrarian.net/155235096/buildlog_ubuntu-trusty-powerpc.openvswitch_2.0.0-0ubuntu1_FAILEDTOBUILD.txt.gz Signed-off-by: James Page <[email protected]> Signed-off-by: Ben Pfaff <[email protected]>
zubryan · Dec 5, 2013 · fd2e50c · fd2e50c
1 parent fabbb97
commit fd2e50c
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diff --git a/configure.ac b/configure.ac
@@ -83,6 +83,7 @@ OVS_CHECK_XENSERVER_VERSION
 OVS_CHECK_GROFF
 OVS_CHECK_GNU_MAKE
 OVS_CHECK_TLS
+OVS_CHECK_ATOMIC_LIBS
 OVS_CHECK_GCC4_ATOMICS
 OVS_CHECK_ATOMIC_ALWAYS_LOCK_FREE(1)
 OVS_CHECK_ATOMIC_ALWAYS_LOCK_FREE(2)

diff --git a/m4/openvswitch.m4 b/m4/openvswitch.m4
@@ -432,6 +432,12 @@ static thread_local int var;], [return var;])],
      fi
    fi])
 
+dnl OVS_CHECK_ATOMIC_LIBS
+dnl
+dnl Check to see if -latomic is need for GCC atomic built-ins.
+AC_DEFUN([OVS_CHECK_ATOMIC_LIBS],
+   [AC_SEARCH_LIBS([__atomic_load_8], [atomic])])
+
 dnl OVS_CHECK_GCC4_ATOMICS
 dnl
 dnl Checks whether the compiler and linker support GCC 4.0+ atomic built-ins.