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Re: [whopr] Design/implementation alternatives for the driver and WPA
On Thu, Jun 5, 2008 at 11:09, Jan Hubicka <hubicka@ucw.cz> wrote:
> I think one problem is that both repackaging and cherry picking as
> described is very centric about application on inlining.
No, that's simply the main application for the initial implementation.
Any other summary-based transformation can be supported the same way.
Optimizations that are not summary-based can be done the way they're
done today. All that happens is that they won't be able take
advantage of the partitioning and distribution since WPA and LTRANS
will be executed together.
And of course, even summary-based transformations can be done the same
way they are done today. The scaling aspects of WHOPR should only
kick in via a special option, or even via heuristics.
> I personally always leaned to kind of repackaging scheme. I've hoped
> that with sanely designed LTO dumping scheme, this will be relatively
> straighforward to implement: simply you re-use same serialized functions
> as they are in the original .o files and replace function summaries by
> transformation summaries, so we might pretty much re-use same
> infrastructure. With sane caching mechanizm to keeping unmodified
> function bodies in memory in cooperation in GGC, the repackaging stage
> should be possible to implement as simple pass through the callgraph
> writting the selected functions to the output file.
Sure. All this is possible and we shouldn't break it.
Diego.