private String getVarnodeKey(VarnodeAST vn) {
		PcodeOp op = vn.getDef();
		String id;
		if (op != null) {
			id = op.getSeqnum().getTarget().toString(true) + " v " +
				Integer.toString(vn.getUniqueId());
		}
		else {
			id = "i v " + Integer.toString(vn.getUniqueId());
		}
		return id;
	}
Task for creating PCode data flow graphs from decompiler output
Ghidra/Features/Decompiler/src/main/java/ghidra/app/plugin/core/decompile/actions/PCodeDfgGraphTask.java