Re: [PATCH v2 1/4] meson: hide tsan related warnings

[Thomas Huth <thuth@redhat.com>]

On 15/08/2024 00.41, Pierrick Bouvier wrote:
> When building with gcc-12 -fsanitize=thread, gcc reports some
> constructions not supported with tsan.
> Found on debian stable.
> 
> qemu/include/qemu/atomic.h:36:52: error: ‘atomic_thread_fence’ is not supported with ‘-fsanitize=thread’ [-Werror=tsan]
>     36 | #define smp_mb()                     ({ barrier(); __atomic_thread_fence(__ATOMIC_SEQ_CST); })
>        |                                                    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
> ---
>   meson.build | 10 +++++++++-
>   1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/meson.build b/meson.build
> index 81ecd4bae7c..52e5aa95cc0 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -499,7 +499,15 @@ if get_option('tsan')
>                            prefix: '#include <sanitizer/tsan_interface.h>')
>       error('Cannot enable TSAN due to missing fiber annotation interface')
>     endif
> -  qemu_cflags = ['-fsanitize=thread'] + qemu_cflags
> +  tsan_warn_suppress = []
> +  # gcc (>=11) will report constructions not supported by tsan:
> +  # "error: ‘atomic_thread_fence’ is not supported with ‘-fsanitize=thread’"
> +  # https://gcc.gnu.org/gcc-11/changes.html
> +  # However, clang does not support this warning and this triggers an error.
> +  if cc.has_argument('-Wno-tsan')
> +    tsan_warn_suppress = ['-Wno-tsan']
> +  endif
> +  qemu_cflags = ['-fsanitize=thread'] + tsan_warn_suppress + qemu_cflags
>     qemu_ldflags = ['-fsanitize=thread'] + qemu_ldflags
>   endif
>   

Not sure if we should hide these warnings ... they seem to be there for a 
reason? Paolo, any ideas?

  Thomas