It looks like fields were added to apl_vm_spec to allow for bytecode caching on the actual spec. I think this is a bad idea. Specs are short-lived, typically stack-allocated, structs which exist to group a bunch of arguments together.
If we choose to re-enable bytecode caching in mod_lua, it should be done as a hook on source code loading where the cache is managed by the bytecode caching module (which may be mod_lua, or may not be) and if the cache hook doesn't fill in the sources, the fallback one loads the file an compiles them. -Brian
