For this to happen, the incrementally loaded code must use the perl stack, look at sample.c to get a better idea. All functions and non-static variables become visible from within perl. This function returns a pointer to an internal hash table corresponding to the symbol table of the newly loaded code. There is very little documentation, maybe something to do for a future release. The files sample.o, and sample2.o contain code to be incrementally loaded, test.pl is the test perl script.
Comments are welcome.
I submit this code for public consumption and, basically, am not responsible for it in any way. The undump program comes from the TeX distribution. If you have TeX, then you may have a working undump. You'll have to add unexec.o to the objects line in the Makefile. If you succeed, post to comp.lang.perl.misc about your experience so others can benefit from it.