[HarfBuzz] Questionable use of DEBUG

[John Emmas]

On 27/04/2013 18:06, John Emmas wrote:
> Line 568 of 'hb-private.hh looks like this:-
>
>         #define DEBUG(WHAT) (DEBUG_LEVEL (WHAT, 0))
>
> It's making me feel uneasy because DEBUG will be defined, even for a 
> Release build.  Is that the intended behaviour?
>

On 27/04/2013 21:37, Behdad Esfahbod wrote:
>
> The debug is fine.  The if gets optimized out by the compiler.  That's 
> by design.
>

Hi Behdad.  Can I ask how confident you are about this (for example, is 
there something in the Harfbuzz code to guarantee that there won't be a 
DEBUG macro when we're building our Release code?)  I discussed this 
with some colleagues this morning but the consensus was that a compiler 
itself can't be relied upon to optimize away the DEBUG macro.  But if 
Harfbuzz is written to take care of it, that should be fine.  Thanks.

John