如何检查两个golang函数的调用关系？

I am working on a code static analysis, and I have a challenge now. For example I have two go source file.

a.go

package test1
func Func1() {
    test2.Func2()
    fmt.println("func1")
}

b.go

package test2
func Func2() {
    fmt.println("func2")
}

How to check if func1 ast node has invoke relation with func2 ast node in Golang?