How to enable font lock for functions called by other functions

[doyoucy]

Hi all,

I noticed that the "Font Lock Function Name Face" just enables the
font lock for function name when I decalare new function. But other
functions called by this outer function don't have any color.

For example:
void foo1()
{
    foo2();
}

The function foo1 has font-lock enabled and function foo2 is just
plain text.
So, is there any options to enable the font lock for inside fuunctions
(foo2)?

I'm using GNU Emacs 22.2.1, thanks!