How to get positional information of a variable declaration?

["Sung-taek Lim" <stlim at dynalith dot com>]

In expand_expr(), when I meet a VAR_DECL, I want to do some operation on it

if it was first declared in a given position. For example, I want to determine 

if the integer variable was declared in the second sub-block of the first basic

block of function main(). I illustratd it as follows.

 

int main()

{

        int a;

        {

        }

 

        {

              int b;

              {

                  b;      // I want to do something on b

                  a;      // not a

              }

        }

}

 

Does anybody know easy way to implement the determination?

 

---
Sung-taek Lim