Two changes:

 1. Functions do not make things incomplete, only variables
 2. Constant global variables no longer need to be marked incomplete, because
    we are guaranteed that the initializer for the global will be in the
    graph we are hacking on now.  This makes resolution of indirect calls happen
    a lot more in the bu pass, supports things like vtables and the C counterparts
    (giant constant arrays of function pointers), etc...

Testcase here: test/Regression/Analysis/DSGraph/constant_globals.ll

llvm-svn: 11852