[PATCH] Maintain order of LTO sections

[Andi Kleen]

On Tue, Oct 04, 2011 at 03:08:02PM +0200, Richard Guenther wrote

> Sure, the question is if "-flto" counts as magic and thus
> "don't do it when it hurts" ;))  I suppose with -flto-partition=none
> (or 1to1) it would be reasonable to make -fno-toplevel-reorder work
> (and thus maybe -fno-toplevel-reorder should simply force 1to1 
> partitioning).

At least =none is incredible slow for larger programs. I would really
prefer normal whopr, otherwise at some point LTO becomes unpracticable
due to the extreme compile time penalty. I can use it right now as 
a workaround, but it's not a long term solution.

What I really want is not full -fno-toplevel-reorder anyways, but just
marking a few special variables with a special attribute to not
reorder. But this patch is still needed even for that and likely a good 
idea anyways for the other reasons.

-Andi