RSSA

[Stephen Weeks]

> The solution that I've mostly got working is to copy the returned value to
> a global static location, transfer to the CReturn, and then copy the 
> value to it's final destination. 

That's what I did in the C codegen.

> There is also the C-calling convention which requires the caller to pop
> the c-stack of callee arguments.  Technically, this seems like a CReturn
> type of operation, but we don't know the number and/or size of the
> arguments there.  It seems really messy to pass an args list to each
> CReturn.  It's not a big deal; the pop is trivial (i.e., won't touch
> any registers besides %esp) and can be done before transfering to the
> CReturn.

Fine.  But I don't mind adding it to the CReturn as well.