static Function getCalledFunction(Program program, PcodeOp op) {
		if (op.getOpcode() != PcodeOp.CALL) {
			return null;
		}
		Address addr = op.getInput(0).getAddress();
		FunctionManager functionManager = program.getFunctionManager();
		Function function = functionManager.getFunctionAt(addr);
		if (function != null) {
			return function;
		}
		Address opAddr = op.getSeqnum().getTarget();
		Reference[] references = program.getReferenceManager().getFlowReferencesFrom(opAddr);
		for (Reference ref : references) {
			if (ref.getReferenceType().isCall()) {
				function = functionManager.getFunctionAt(ref.getToAddress());
				if (function != null) {
					return function;
				}
			}
		}
		return null;
	}
Try to find the PcodeOp representing the call the user has selected
@param program is the Program
@param tokenAtCursor is the point in the window the user has selected
@return the PcodeOp or null
Ghidra/Features/Decompiler/src/main/java/ghidra/app/plugin/core/decompile/actions/OverridePrototypeAction.java