On 2010-02-08, Kaz Kylheku <kkylheku@gmail.com> wrote:
> Here is a gem: they decided that it's okay to generate deliberately broken
> code when the function can detect at compile time that a function pointer
> is being ``misused'' (cast to a different function type, and used to make
> a call).

Specifically, when it's cast to a function type which does not match the
function *being called*.

And it should give you copious warnings when it triggers that, and it's
fixed as of OpenSSH 0.9.8f or so.

I seem to recall being told by someone closer to the code that the reason
is that otherwise the PPC compiler tended to blow up spectacularly trying
to optimize mismatched calls.

BTW, this sounds *eerily* familiar. When I encountered it, it involved
someone using a heavily-hacked OpenSSH 0.9.8 library, rather than the 0.9.8g
we shipped with that version of the product, because it had some specific
other bit of magic going on that was needed. I told the support people to
point the customer at the specific patches (I think that was 0.9.8f) to
openssh which fixed the calls to use the correct types.

But honestly, overall, I like that one. I am quite happy to have the compiler
throw out fierce warnings about something that is known to have a real chance
of blowing up in exciting ways, and to die cleanly rather than executing
garbage.

-s
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