Now if you want to get these dynamic metrics from the runtime all you
need to do is:
1. Configure Swift with -DSWIFT_RUNTIME_ENABLE_DTRACE=YES
2. Run your routine with the command:
sudo dtrace -s ./utils/runtime_statistics.d -c "$MY_COMMAND_LINE"
After your app finishes running, it will dump out the counts. This is a
much more efficient and low maintenance way to get such statistics than
custom instrumenting the code.
Nothing is changed if -DSWIFT_RUNTIME_ENABLE_DTRACE is not set.
Swift SVN r25264
