I shoulda done this a *long* time ago (tm): implement calls properly,

I shoulda done this a *long* time ago (tm): implement calls properly,
i.e. r1/r12/rp are saved/restored regardless of scheduling/luck

TODO: calls to external symbols, indirect (function descriptor) calls,
      performance (we're being paranoid right now)

BUG: the code for handling calls to vararg functions breaks if FP
args are passed (this will make printf() go haywire so a bunch of
tests will fail)

BUG: this seems to trigger some legalize nastiness

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@24942 91177308-0d34-0410-b5e6-96231b3b80d8