Get function declaration on GCC 3.3

[Le Ton Chanh]

Hi all,
I am using GCC 3.3. In macro INIT_CUMULATIVE_ARGS(CUM, FNTYPE, LIBNAME, INDIRECT), I want to know the declaration of callee function (fndecl). I know the function get_callee_fndecl(call_expr) to use in this case, but I don't know how to get call_expr in this step.
I use callee's fndecl to determine whether passing arguments for callee by registers or by stack by initialize CUM perspective.
Can you help me in this situation? Thanks in advance.

Le Ton Chanh 
email:letonchanh at yahoo dot com