Exceptions workaround for older systems that don't USE_COLLECT2

Melissa O'Neill oneill@cs.sfu.ca
Tue Sep 8 09:26:00 GMT 1998


I wrote:
>>> That's certainly a possible solution and likely the best compromise.
>>> The downside is that collect2 would do static constructor/destructor
>>> handling when NeXT's ld is happy to handle it.  And, since many C++
>>> programs don't use exceptions at all, the overhead of always using
>>> collect2's double-link strategy for those common cases seems a little
>>> burdensome.

... and Jamie Lokier replied:
>> If collect2 doesn't find anything it needs to handle itself (i.e.,
>> exceptions in this case), can it skip the second link and just use
>> the output of the first?

... leading Jeff Law to write:
> Yes.  If collect2 finds nothing to do, then it will not perform a second
> link.
>
> However, I'm not sure if the compiler & collect2 are set up to know
> that the linker will handle some set of issues (ctors/dtors) and that
> collect2 is supposed to handle another set of issues (EH frames).
>
> I'd certainly prefer to have something that worked without user
> intervention even if it was a little bit slower at link time. Thus, my
> preference would be to enable collect2 on NeXT boxes.

I agree. Doing the right thing every time has to be preferred over saving
a bit of time for a few cases. Although, as I said earlier, it'd be cool
if g++ could skip the double-link/collect2 business when -fno-exceptions
is in effect, but I doubt anyone is going to take the time to implement
that (after all, 'tis better to fix bugs than add features, IMHO).

    Melissa.



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