Re: Unofficial buildd network has been shut down
Andrew Suffield <asuffield@debian.org> writes:
> I have no idea. That's a script's job - pairing off basic blocks with
> source sequences. If you have any left over, or any that don't match
> the source, something funky is going on, and you go figure it out by
> hand.
Alas, that'll fail with a fancy optimizing compiler (like GCC), which
freely rearranges basic blocks, changing how many there are and the
like.
> All else aside, that's Halting-equivalent in a number of places. It
> can't be done. Even being able to confuse all that code once would be
> difficult to the point of absurdity - and it would *still* break the
> next time some of it was rewritten in a sufficiently different manner.
Well, the strategy isn't about doing so automatically, but is based
upon a knowledge of the tools you would use to catch the trickery.
You are certainly right that it is likely to be eventually caught if
it is tried. You are also certainly right that it is not something
Debian has to worry about. And I have no opinions about the buildd
topic being discussed, except that it seems like both "sides" have
tried to overstate their case in order to prove it, and I doubt that
my contributions would be well received, so I haven't posted them.
But for the more theoretical question raised, about Thompson's style
of trickery, I thought that I would simply point out that "I'll use
tool X to catch it" isn't actually the right strategy.
Thomas
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