Peter Maydell <peter.mayd...@linaro.org> writes: > This is something clang's -fsanitize=undefined spotted. The > code generated by qapi-commands.py in qmp-marshal.c for > qmp_marshal_* functions where there are some optional > arguments looks like this: > > bool has_force = false; > bool force; > > mi = qmp_input_visitor_new_strict(QOBJECT(args)); > v = qmp_input_get_visitor(mi); > visit_type_str(v, &device, "device", errp); > visit_start_optional(v, &has_force, "force", errp); > if (has_force) { > visit_type_bool(v, &force, "force", errp); > } > visit_end_optional(v, errp); > qmp_input_visitor_cleanup(mi); > > if (error_is_set(errp)) { > goto out; > } > qmp_eject(device, has_force, force, errp); > > In the case where has_force is false, we never initialize > force, but then we use it by passing it to qmp_eject. > I imagine we don't then actually use the value, but clang
Use of FOO when !has_FOO is a bug. > complains in particular for 'bool' variables because the value > that ends up being loaded from memory for 'force' is not either > 0 or 1 (being uninitialized stack contents). > > Anybody understand what the codegenerator is doing well enough > to suggest a fix? I'd guess that just initializing the variable either > at point of declaration or in an else {) clause of the 'if (has_force)' > conditional would suffice, but presumably you need to handle > all the possible data types... I can give it a try. Will probably take a while, though.