Re: [Qemu-devel] [PATCH v3 2/2] trace: Avoid implicit bool->integer conversions

["Daniel P. Berrange" <berrange@redhat.com>]

On Thu, Aug 11, 2016 at 06:41:36PM +0200, Lluís Vilanova wrote:
> Daniel P Berrange writes:
> 
> > On Thu, Aug 11, 2016 at 06:11:29PM +0200, Lluís Vilanova wrote:
> >> An explicit if/else is clearer than arithmetic assuming #true is 1,
> >> while the compiler should be able to generate just as optimal code.
> >> 
> >> Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
> >> ---
> >> stubs/trace-control.c  |    9 +++++++--
> >> trace/control-target.c |   18 ++++++++++++++----
> >> 2 files changed, 21 insertions(+), 6 deletions(-)
> >> 
> >> diff --git a/stubs/trace-control.c b/stubs/trace-control.c
> >> index 3740c38..099c2b5 100644
> >> --- a/stubs/trace-control.c
> >> +++ b/stubs/trace-control.c
> >> @@ -21,8 +21,13 @@ void trace_event_set_state_dynamic(TraceEvent *ev, bool state)
> >> TraceEventID id;
> >> assert(trace_event_get_state_static(ev));
> >> id = trace_event_get_id(ev);
> >> -    trace_events_enabled_count += state - trace_events_dstate[id];
> >> -    trace_events_dstate[id] = state;
> >> +    if (state) {
> >> +        trace_events_enabled_count++;
> >> +        trace_events_dstate[id] = 1;
> >> +    } else {
> >> +        trace_events_enabled_count--;
> 
> > SHouldn't this be trace_events_enabled_count -= trace_events_dstate[id];
> > as it is possible to call this method for a trace event that is a per-vcpu
> > event
> 
> The "stub" code will never have vCPUs around, it's used by qemu-img and the like
> (any program without "target" code).

I just picked the first example of that in this file - you've got the same
pattern in the other 2 places you change

Regards,
Daniel
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