Re: Display performance degradation

[YAMAMOTO Mitsuharu]

>>>>> On Sat, 19 Dec 2009 11:00:56 +0100, Andreas Schwab <address@hidden> said:

> YAMAMOTO Mitsuharu <address@hidden> writes:
>> 4490             if (XINT (XCAR (val)) == 0)
>> 4491               {
>> 4492                 font_clear_cache (f, XCAR (val), driver_list->driver);
>> 4493                 XSETCDR (cache, XCDR (val));
>> 4494               }
>> 4495           }
>> 
>> At line 4490, XCAR (val) is expected to be of type Lisp integer.  But
>> it is also passed to font_clear_cache at line 4492, which seems to
>> expect the value of `val' as of line 4488 rather than the one assigned
>> at line 4489.

> If the condition is ever true then Emacs crashes.  I've checked in a
> fix.  But then, I don't think this function is ever more than a no-op
> anyway, since as soon as NUM-FRAMES becomes zero the cache is cleared
> automatically anyway.

That's another reason I posted it rather than installing a trivial fix
myself silently.  If the code has never be executed, it might contain
more hidden problems than those can easily be found with simple type
checking by hand.

                                     YAMAMOTO Mitsuharu
                                address@hidden