Re: [PATCH 01/10] qapi: expose rtc-reset-reinjection command unconditionally

[Pierrick Bouvier <pierrick.bouvier@linaro.org>]

On 5/12/25 11:33 AM, Daniel P. Berrangé wrote:
>>> diff --git a/stubs/monitor-i386-rtc.c b/stubs/monitor-i386-rtc.c
>>> new file mode 100644
>>> index 0000000000..ee2e60d95b
>>> --- /dev/null
>>> +++ b/stubs/monitor-i386-rtc.c
>>> @@ -0,0 +1,10 @@
>>> +/* SPDX-License-Identifier: GPL-2.0-or-later */
>>> +
>>> +#include "qemu/osdep.h"
>>> +#include "qapi/error.h"
>>> +#include "qapi/qapi-commands-misc-i386.h"
>>> +
>>> +void qmp_rtc_reset_reinjection(Error **errp)
>>> +{
>>> +    /* Nothing to do since non-x86 machines lack an RTC */
>>> +}
>>
>> I think I'd create one stub file per qapi/<foo>-<target>.json.
> 
> That's what I started doing but I forgot that doesn't work out well
> with the linker.
> 
> The linker's granularity for dropping stubs is per-file, not per-symbol.
> 
> If /any/ method in a stub/nnn.c file is needed, the linker will pull in
> all methods. This results in duplicate symbol errors if only a subset
> of stub methods were actually needed.
>

Richard mentioned this behaviour as well, but I could not see where it 
is implemented in our build system.

The only thing possibly related is the undefsyms mechanic, but from what 
I understand, it's only for ensuring modules can be linked.

> This forces us to have a separate stub file per build configuration
> scenario that can affect use of stubs.
>
> With regards,
> Daniel