public Varnode[] getKilledByCallList() {
		if (killedbycall == null) {
			killedbycall = new Varnode[0];
		}
		return killedbycall;
	}
@return list of registers definitely affected by called functions
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/model/lang/PrototypeModel.java