Output function name for the "pre-prologue" entry, by stealing
it from the next entry.
Output length of basic-block in bytes and product of executions
and length.
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
