From d2958fb0b6c7bcd8c4e6c0222554ef25d62ecef0 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Date: Mon, 28 Feb 2022 16:03:09 +0400 Subject: [PATCH] meson: fix CONFIG_ATOMIC128 check MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The current testing code isn't correct and matching QEMU usage: testfile.c: In function 'main': testfile.c:5:11: error: incorrect number of arguments to function '__atomic_load' 5 | y = __atomic_load(&x, 0); | ^~~~~~~~~~~~~ testfile.c:6:7: error: argument 2 of '__atomic_store' must be a pointer type 6 | __atomic_store(&x, y, 0); | ^~~~~~~~~~~~~~ testfile.c:7:7: error: argument 3 of '__atomic_compare_exchange' must be a pointer type 7 | __atomic_compare_exchange(&x, &y, x, 0, 0, 0); | ^~~~~~~~~~~~~~~~~~~~~~~~~ Replace the test with common atomics test for u64 and u128 that matches better QEMU needs. Signed-off-by: Marc-André Lureau Reviewed-by: Richard Henderson Reviewed-by: Philippe Mathieu-Daudé --- meson.build | 27 ++++++++++++--------------- 1 file changed, 12 insertions(+), 15 deletions(-) diff --git a/meson.build b/meson.build index 85f3f84ec6..58520aab50 100644 --- a/meson.build +++ b/meson.build @@ -1853,21 +1853,23 @@ 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 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; @@ -1882,15 +1884,10 @@ has_int128 = cc.links(''' config_host_data.set('CONFIG_INT128', has_int128) if has_int128 - has_atomic128 = cc.links(''' - int main(void) - { - unsigned __int128 x = 0, y = 0; - y = __atomic_load(&x, 0); - __atomic_store(&x, y, 0); - __atomic_compare_exchange(&x, &y, x, 0, 0, 0); - return 0; - }''') + # "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)