net/sfc: fix broken build with clang 3.4.x
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Commit Message
Old clanng requires libatomic as well as gcc. Avoid compiler name and
version based checks. Add custom test for 16-byte atomic operations
to find out if libatomic is required to build.
Bugzilla ID: 760
Signed-off-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
---
drivers/net/sfc/meson.build | 22 +++++++++++++++-------
1 file changed, 15 insertions(+), 7 deletions(-)
@@ -40,8 +40,20 @@ foreach flag: extra_flags
endif
endforeach
-# for gcc compiles we need -latomic for 128-bit atomic ops
-if cc.get_id() == 'gcc'
+# for gcc and old Clang compiles we need -latomic for 128-bit atomic ops
+atomic_check_code = '''
+int main(void)
+{
+ __int128 a = 0;
+ __int128 b;
+
+ b = __atomic_load_n(&a, __ATOMIC_RELAXED);
+ __atomic_store(&b, &a, __ATOMIC_RELAXED);
+ __atomic_store_n(&b, a, __ATOMIC_RELAXED);
+ return 0;
+}
+'''
+if not cc.links(atomic_check_code)
libatomic_dep = cc.find_library('atomic', required: false)
if not libatomic_dep.found()
build = false
@@ -51,11 +63,7 @@ if cc.get_id() == 'gcc'
# libatomic could be half-installed when above check finds it but
# linkage fails
- atomic_link_code = '''
- #include <stdio.h>
- void main() { printf("libatomic link check\n"); }
- '''
- if not cc.links(atomic_link_code, dependencies: libatomic_dep)
+ if not cc.links(atomic_check_code, dependencies: libatomic_dep)
build = false
reason = 'broken dependency, "libatomic"'
subdir_done()