private VirtualBaseTableEntry existing(int tableIndex) throws PdbException {
		VirtualBaseTableEntry entry = entry(tableIndex);
		if (entry == null) {
			throw new PdbException(
				"No entry in Virtual Base Table for table offset: " + tableIndex);
		}
		return entry;
	}
Returns the entry for the table index; the table index is based at 1
@param tableIndex the index location in the table
@return the entry
Ghidra/Features/PDB/src/main/java/ghidra/app/util/pdb/classtype/ProgramVirtualBaseTable.java