On 03/31/15 08:23 PM, Matt Turner wrote:
I suspect you did most of this with Coccinelle,
That would have been smart, one of these days I should install Coccinelle
and learn to use it. Fortunately, this wasn't an overwhelming number to
change by hand.
but I definitely
noticed an attention to detail that shows that some of this must have
been manual. E.g., transforming malloc(3 * size * sizeof(CARD16)) into
| xallocarray(length, 3 * sizeof(CARD16))
instead of
| xallocarray(3 * length, sizeof(CARD16))
so that the 3 * sizeof(CARD16) can be evaluated at compile time.
Yes, and because I can guarantee that 3 * sizeof(CARD16) will never overflow,
while I can't say the same for 3 * length.
Nice of you to get rid of some useless casts as well.
That's just ingrained habit at this point (though I tried to avoid breaking
Xvnc again by changing any in the headers - I should do a build to check that
though).
It's minorly unfortunate that a lot of these multiplies (that are by
powers of two) can no longer be turned into shifts, but I guess that's
the price of some additional safety.
Since this math leads immediately into the memory allocator, I doubt anyone
will ever measure the performance change of one additional multiply in this
code path compared to the far larger number of instructions used in memory
allocation.
--
-Alan Coopersmith- alan.coopersm...@oracle.com
Oracle Solaris Engineering - http://blogs.oracle.com/alanc
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