1 files changed, 42 insertions, 6 deletions
diff --git a/meson.build b/meson.build
index f71e1a1468..aef724ad3c 100644
--- a/meson.build
+++ b/meson.build
@@ -1853,21 +1853,57 @@ config_host_data.set('HAVE_BROKEN_SIZE_MAX', not cc.compiles('''
         return printf("%zu", SIZE_MAX);
     }''', args: ['-Werror']))
 
-# See if 64-bit atomic operations are supported.
-# Note that without __atomic builtins, we can only
-# assume atomic loads/stores max at pointer size.
-config_host_data.set('CONFIG_ATOMIC64', cc.links('''
+atomic_test = '''
   #include <stdint.h>
   int main(void)
   {
-    uint64_t x = 0, y = 0;
+    @0@ x = 0, y = 0;
     y = __atomic_load_n(&x, __ATOMIC_RELAXED);
     __atomic_store_n(&x, y, __ATOMIC_RELAXED);
     __atomic_compare_exchange_n(&x, &y, x, 0, __ATOMIC_RELAXED, __ATOMIC_RELAXED);
     __atomic_exchange_n(&x, y, __ATOMIC_RELAXED);
     __atomic_fetch_add(&x, y, __ATOMIC_RELAXED);
     return 0;
-  }'''))
+  }'''
+
+# See if 64-bit atomic operations are supported.
+# Note that without __atomic builtins, we can only
+# assume atomic loads/stores max at pointer size.
+config_host_data.set('CONFIG_ATOMIC64', cc.links(atomic_test.format('uint64_t')))
+
+has_int128 = cc.links('''
+  __int128_t a;
+  __uint128_t b;
+  int main (void) {
+    a = a + b;
+    b = a * b;
+    a = a * a;
+    return 0;
+  }''')
+
+config_host_data.set('CONFIG_INT128', has_int128)
+
+if has_int128
+  # "do we have 128-bit atomics which are handled inline and specifically not
+  # via libatomic". The reason we can't use libatomic is documented in the
+  # comment starting "GCC is a house divided" in include/qemu/atomic128.h.
+  has_atomic128 = cc.links(atomic_test.format('unsigned __int128'))
+
+  config_host_data.set('CONFIG_ATOMIC128', has_atomic128)
+
+  if not has_atomic128
+    has_cmpxchg128 = cc.links('''
+      int main(void)
+      {
+        unsigned __int128 x = 0, y = 0;
+        __sync_val_compare_and_swap_16(&x, y, x);
+        return 0;
+      }
+    ''')
+
+    config_host_data.set('CONFIG_CMPXCHG128', has_cmpxchg128)
+  endif
+endif
 
 config_host_data.set('CONFIG_GETAUXVAL', cc.links(gnu_source_prefix + '''
   #include <sys/auxv.h>