private Map<Address, List<Address>> createMapOfVftableRefs(List<Address> vtableList,
			Map<Address, GccTypeinfoRef> map) throws CancelledException {

		Map<Address, List<Address>> refmap = new HashMap<Address, List<Address>>();
		for (Address vtableAddr : vtableList) {
			monitor.checkCancelled();

			GccTypeinfoRef typeinfoRef = map.get(vtableAddr);
			Address topOfVfunctions = typeinfoRef.getAddress().add(defaultPointerSize);

			// null means no vfunctions for this vtable
			if (!isVirtualFunctionTable(topOfVfunctions)) {
				refmap.put(vtableAddr, null);
				continue;
			}

			refmap.put(vtableAddr, getAllReferencesTo(topOfVfunctions));
		}

		return refmap;
	}
method to find the main vtable for the given typeinfo and if any, add the
construction ones to the passed in list

@param typeinfo
@param map
@param constructionVtables
@param numBaseRefs
@return address of main vtable for this class
@throws CancelledException
Ghidra/Features/Decompiler/ghidra_scripts/classrecovery/RTTIGccClassRecoverer.java