GCC added an implicit-fallthrough warning a while back, where it
would complain if you had a nontrivial "case:" block that didn't end
with break, return, or something like that. Clang recently added
the same thing.
GCC, however, would let you annotate a fall-through as intended by
any of various magic "/* fall through */" comments. Clang, however,
only seems to like "__attribute__((fallthrough))". Fortunately, GCC
accepts that too.
A previous commit in this branch defined a FALLTHROUGH macro to do
the right thing if GNUC is defined; here we replace all of our "fall
through" comments with uses of that macro.
This is an automated commit, made with the following perl one-liner:
#!/usr/bin/perl -i -p
s#/\* *falls? ?thr.*?\*/#FALLTHROUGH;#i;
(In order to avoid conflicts, I'm applying this script separately to
each maint branch. This is the 0.4.3 version.)
Coverity has had trouble figuring out our csiphash implementation,
and has given spurious warnings about its behavior.
This patch changes the csiphash implementation when coverity is in
use, so that coverity can figure out that we are not about to read
beyond the provided input.
Closes ticket 31025.
The 64-bit load and store code was generating pretty bad output with
my compiler, so I extracted the code from csiphash and used that instead.
Close ticket 21737
The compiler is allowed to assume that a "uint64_t *" is aligned
correctly, and will inline a version of memcpy that acts as such.
Use "uint8_t *", so the compiler does the right thing.
In digestmap_set/get benchmarks, doing unaligned access on x86
doesn't save more than a percent or so in the fast case. In the
slow case (where we cross a cache line), it could be pretty
expensive. It also makes ubsan unhappy.
siphash is a hash function designed for producing hard-to-predict
64-bit outputs from short inputs and a 128-bit key. It's chosen for
security and speed.
See https://131002.net/siphash/ for more information on siphash.
Source: https://github.com/majek/csiphash/
