1. Clone the subrefs
2. Remove the ops which create the callframe and set @_ to the params passed in (except for the first one).
3. Add in an op for a label at the end of the tree corresponding to SUB_N: (where N is the sub #.
4. Replace the ops for "return (...)" with ops for "@_ = (...);goto SUB_N;" (except for the last one).
5. String the converted subrefs together.

I'm figuring that the lexical pads don't need to be messed with because the ops should be referring to them by memory address. And, I do want the addresses to remain the same when cloning. The reason being:

{
   my $counter;
   sub inc_counter { $counter++ }
}
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If I chain inc_counter(), I want it to keep incrementing $counter. Maybe it is an option to clone_subref()?

I figured that B::Generate should be able to do this very easily, except I haven't the foggiest where to start. :-)