Re: [PATCH v2 2/3] hw/mips/gt64xxx: Remove dynamic field width from trace events

[Eric Blake]

On 11/18/19 1:10 PM, Philippe Mathieu-Daudé wrote:

> > > > -        trace_gt64120_write("INTRCAUSE", size << 1, val);
> > > > +        trace_gt64120_write("INTRCAUSE", size << 3, val);
> > >
> > > Again, this isn't mentioned in the commit message.  Why are you 
> > > changing parameter values?
> > >
> > >
> > > > +++ b/hw/mips/trace-events
> > > > @@ -1,4 +1,4 @@
> > > >   # gt64xxx.c
> > > > -gt64120_read(const char *regname, int width, uint64_t value) 
> > > > "gt64120 read %s value:0x%0*" PRIx64
> > > > -gt64120_write(const char *regname, int width, uint64_t value) 
> > > > "gt64120 write %s value:0x%0*" PRIx64
> > > > +gt64120_read(const char *regname, int width, uint64_t value) 
> > > > "gt64120 read %s width:%d value:0x%08" PRIx64
> > > > +gt64120_write(const char *regname, int width, uint64_t value) 
> > > > "gt64120 write %s width:%d value:0x%08" PRIx64
> > >
> > > Huh, we were really broken - the old code (if passed to printf) would 
> > > try to parse 4 parameters, even though it was only passed 3.  But it 
> > > looks like you still need a v3.
> >
> > Oops. I am surprise the compiler doesn't emit a warning here...
>
> I'm sorry I can't see the 4th parameter.

My fault for chasing a red herring.  I guess I was mixing the three % 
post-patch with the two % and one * pre-patch, and somehow mis-counting 
three % plus one * as four arguments.  But re-reading your confusion, 
yes, there were only three parameters being consumed.

> Before: "gt64120 read %s value:0x%0*" PRIx64
>
> #1 's' for 'const char *regname'
> #2 '0*' for 'int width'
> #3 'x' for 'uint64_t value'
>
> After: "gt64120 read %s width:%d value:0x%08" PRIx64
>
> #1 's' for 'const char *regname'
> #2 'd' for 'int width'
> #3 '08x' for 'uint64_t value'
>
> Am I missing something?

Rather, I was.

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
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