meson: Warn when TCI is selected but TCG backend is available

Some new users get confused with 'TCG' and 'TCI', and enable TCI
support expecting to enable TCG.

Emit a warning when native TCG backend is available on the
host architecture, mentioning this is a suboptimal configuration.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Suggested-by: Daniel Berrangé <berrange@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20210125144530.2837481-5-philmd@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/meson.build b/meson.build
index 3a13ba3307c309b83e1c1ed447b693e35a87be4e..4cc3ebb827e10c2d96338257d3a70ec77bd4cb16 100644 (file)
--- a/meson.build
+++ b/meson.build
@@ -231,6 +231,13 @@ if not get_option('tcg').disabled()
     else
       error('Unsupported CPU @0@, try --enable-tcg-interpreter'.format(cpu))
     endif
+  elif get_option('tcg_interpreter')
+    warning('Use of the TCG interpretor is not recommended on this host')
+    warning('architecture. There is a native TCG execution backend available')
+    warning('which provides substantially better performance and reliability.')
+    warning('It is strongly recommended to remove the --enable-tcg-interpreter')
+    warning('configuration option on this architecture to use the native')
+    warning('backend.')
   endif
   if get_option('tcg_interpreter')
     tcg_arch = 'tci'