In the Synergy/DE language on Windows, we have a runtime-bound DLL interface, which uses GetProcAddress to look up DLL routines when they're called. A seemingly reasonable optimization for this would be to hash previously acquired name/address pairs, but when we hacked up a prototype and tested it, we found absolutely no improvement, even over millions of calls. Apparently, GetProcAddress does something like that already internally, so our optimization would have been a complete waste of programmer resources.