configure.ac/meson.build: Fix -latomic test

When compiling with LLVM 6.0 on x86 (32-bit) for Android, the test
fails to detect that -latomic is actually required, as the atomic
call is inlined.

In the code itself (src/util/disk_cache.c), we see this pattern:
p_atomic_add(cache->size, - (uint64_t)size);
where cache->size is an uint64_t *, and results in the following
link time error without -latomic:
src/util/disk_cache.c:628: error: undefined reference to '__atomic_fetch_add_8'

Fix the configure/meson test to replicate this pattern, which then
correctly realizes the need for -latomic.

Reviewed-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
This commit is contained in:
Nicolas Boichat 2018-04-05 09:33:09 +08:00 committed by Matt Turner
parent 8b519075ea
commit 54ba73ef10
2 changed files with 8 additions and 4 deletions

View File

@ -445,9 +445,11 @@ if test "x$GCC_ATOMIC_BUILTINS_SUPPORTED" = x1; then
AC_MSG_CHECKING(whether -latomic is needed)
AC_LINK_IFELSE([AC_LANG_SOURCE([[
#include <stdint.h>
uint64_t v;
struct {
uint64_t *v;
} x;
int main() {
return (int)__atomic_load_n(&v, __ATOMIC_ACQUIRE);
return (int)__atomic_load_n(x.v, __ATOMIC_ACQUIRE);
}]])], GCC_ATOMIC_BUILTINS_NEED_LIBATOMIC=no, GCC_ATOMIC_BUILTINS_NEED_LIBATOMIC=yes)
AC_MSG_RESULT($GCC_ATOMIC_BUILTINS_NEED_LIBATOMIC)
if test "x$GCC_ATOMIC_BUILTINS_NEED_LIBATOMIC" = xyes; then

View File

@ -849,8 +849,10 @@ if cc.compiles('int main() { int n; return __atomic_load_n(&n, __ATOMIC_ACQUIRE)
# as ARM.
if not cc.links('''#include <stdint.h>
int main() {
uint64_t n;
return (int)__atomic_load_n(&n, __ATOMIC_ACQUIRE);
struct {
uint64_t *v;
} x;
return (int)__atomic_load_n(x.v, __ATOMIC_ACQUIRE);
}''',
name : 'GCC atomic builtins required -latomic')
dep_atomic = cc.find_library('atomic')