private FGVertex getVertex(FGController controller, Map<AddressHasher, FGVertex> vertexMap,
			AddressInfo addressInfo) {

		Program program = controller.getProgram();
		AddressFactory addressFactory = program.getAddressFactory();
		Address minAddress = addressFactory.getAddress(addressInfo.addressRangeStart);
		Address maxAddress = addressFactory.getAddress(addressInfo.addressRangeEnd);
		AddressHasher addressHasher = new AddressHasher(minAddress, maxAddress);
		FGVertex vertex = vertexMap.get(addressHasher);
		if (vertex == null) {
			return null;
		}

		vertex.setLocation(getVertexLocation());

		return vertex;
	}
Finds an existing vertex represented by this info.  Returns null if no vertex exists to 
match this info (this can happen if the code block structure has changed).

@param controller The controller used for the current function graph
@return an existing vertex represented by this info.  Returns null if no vertex exists to 
        match this info
Ghidra/Features/FunctionGraph/src/main/java/ghidra/app/plugin/core/functiongraph/graph/vertex/VertexInfo.java