travis: keep meson version below 0.45.0

[mesa.git] / meson.build

diff --git a/meson.build b/meson.build
index e9928a379313edbfc96a280d869a5a2e43d7803e..bb6a835084fe777813c07d60357f644448c6f2d1 100644 (file)
--- a/meson.build
+++ b/meson.build
@@ -790,9 +790,26 @@ else
 endif
 
 # Check for GCC style atomics
+dep_atomic = declare_dependency()
+
 if cc.compiles('int main() { int n; return __atomic_load_n(&n, __ATOMIC_ACQUIRE); }',
                name : 'GCC atomic builtins')
   pre_args += '-DUSE_GCC_ATOMIC_BUILTINS'
+
+  # Not all atomic calls can be turned into lock-free instructions, in which
+  # GCC will make calls into the libatomic library. Check whether we need to
+  # link with -latomic.
+  #
+  # This can happen for 64-bit atomic operations on 32-bit architectures such
+  # as ARM.
+  if not cc.links('''#include <stdint.h>
+                     int main() {
+                       uint64_t n;
+                       return (int)__atomic_load_n(&n, __ATOMIC_ACQUIRE);
+                     }''',
+                  name : 'GCC atomic builtins required -latomic')
+    dep_atomic = cc.find_library('atomic')
+  endif
 endif
 if not cc.links('''#include <stdint.h>
                    uint64_t v;