public Varnode getStackVarnode() {
		if (stackVarnode != null) {
			return stackVarnode;
		}

		Register stackRegister = getStackRegister();
		if (stackRegister == null) {
			return null;
		}

		stackVarnode = trans.getVarnode(stackRegister);
		return stackVarnode;
	}
@return Varnode that represents the stack register
Ghidra/Features/Base/src/main/java/ghidra/program/util/VarnodeContext.java