@Override
	public synchronized long getKey(Address addr, boolean create) {
		if (useOldAddrMap) {
			return oldAddrMap.getKey(addr, create);
		}
		try {
			return encodeRelative(addr, false, create ? INDEX_CREATE : INDEX_MATCH);
		}
		catch (IllegalArgumentException e) {
			return INVALID_ADDRESS_KEY;
		}
	}
Returns an address map which may be used during the upgrade of old address
encodings.  If the address map is up-to-date, then this method will return
this instance of AddressMapDB.
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/map/AddressMapDB.java