API for callgraph and IPA passes for whole program optimization

[Kenneth Zadeck]

>
> Thanks for the detailed plan.  Yes, please add it to the whopr wiki.
> The only aspects that are not too clear to me are what exactly do you
> plan to do in mainline.
>
> One idea would be to do all the basic framework during stage 1 and
> leave it in mainline.   I would suggest doing as much as possible in
> mainline, so that it's then pulled in by the LTO branch.
>
> Kenny, what do you expect we could pull out from the LTO branch for
> stage 1?  Does it make sense to open a new branch inheriting from LTO
> for this work?
>
>
I am a not an expert on branches and merging and such.  I worry about
trying to pull all of these different branch that are touching the same
parts of the compiler, back together at the end. 

I would prefer that honza work on the lto branch and that we selectively
pull patches from that and put them on the mainline. 

Kenny


> Thanks.  Diego.
>