On Fri, Mar 24, 2023 at 11:35:52AM +0100, Michal Prívozník wrote:

On 3/24/23 08:33, Martin Kletzander wrote:

...

On Tue, Mar 21, 2023 at 05:47:19PM +0100, Michal Privoznik wrote:

...

There are some CLang versions that do not support -fsemantic-interposition. If that's the case, the code is optimized so much that our mocking no longer works.

Therefore, disable tests and produce a warning.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com> ---

Technically, this is a v2 of:

https://listman.redhat.com/archives/libvir-list/2023-March/238943.html

but a different approach is implemented, so I'm sending it anew.

meson.build | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/meson.build b/meson.build index a0682e8d0b..c15003ce02 100644 --- a/meson.build +++ b/meson.build @@ -2035,8 +2035,18 @@ subdir('src')

subdir('tools')

-build_tests = not get_option('tests').disabled() -if build_tests +build_tests = [ not get_option('tests').disabled() ] +if build_tests[0] and \ +   cc.get_id() == 'clang' and \ +   not supported_cc_flags.contains('-fsemantic-interposition') \ +   and get_option('optimization') != '0' +   # If CLang doesn't support -fsemantic-interposition then our +   # mocking doesn't work. The best we can do is to not run the +   # test suite. +   build_tests = [ false, '!!! Forcibly disabling tests because CLang lacks -fsemantic-interposition. Update CLang or disable optimization !!!' ] +endif +

So at first I wanted to suggest something like:

if cc.get_id() == 'clang' and \    not supported_cc_flags.contains('-fsemantic-interposition') \    and get_option('optimization') != '0'   # If CLang doesn't support -fsemantic-interposition then our   # mocking doesn't work. The best we can do is to not run the   # test suite.   if get_option('tests').enabled()     error('Cannot enable tests because CLang lacks -fsemantic-interposition. Update CLang or disable optimization')   else     build_tests = false   endif else   build_tests = not get_option('tests').disabled() endif

Which would simply error out if you want the tests to be enabled on such system.  However that has the downside that some potential contributor might not notice the tests are being disabled and we would also have to have another place where to track the enablement of tests/optimization, in our CI.  It is possible, but after some tries I think your approach is better and the main thing is that we need something to be pushed in order for us not to get into failing CI fatigue which I've seen in other projects where CI failures are just being dismissed after couple of issues.  So:

Reviewed-by: Martin Kletzander <mkletzan@redhat.com>

Thanks. I think it's important to note that this affects systems with old CLang and I don't expect many developers there (in fact none). Except for our CI which can be easily fixed - just pass -O0 in CFLAGS.

Which is another thing that needs adjustment. I think if you adjust it right now just for macos-12 and then update the CI files in the same commit then we'll get a green pipeline *with* no tests skipped because of clang for a change ;)

Michal