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SubjectRe: List of all-zero .data variables in linux-2.4.3 available
>> = Adam Richter
> = Ulrich Drepper

>> >Shouldn't a compiler be able to deal with this instead?
>> Yes.

>No. gcc must not do this. There are situations where you must place
>a zero-initialized variable in .data. It is a programmer problem.

I am aware of a couple of cases where code relied on static
variables being allocated contiguously, but, in both cases, those
variables were either all zeros or all non-zeros, so my proposed
change would not break such code. Also, variables being allocated
contiguously is not an assumption supported by any standard that
I am aware of, and the very rare cases where code relies on this
should instead use an array (they've been of the same type in the
examples that I have come across). At the very least, it seems
to me that this should be a compiler optimization flag, preferably
defaulted to "on".

If you have some other scenario in mind, I'd appreciate an
example or a clear reference to some explanation, and I think others
on linux-kernel would probably appreciate that too. It is a topic
that comes up repeatedly on linux-kernel.

Adam J. Richter __ ______________ 4880 Stevens Creek Blvd, Suite 104 \ / San Jose, California 95129-1034
+1 408 261-6630 | g g d r a s i l United States of America
fax +1 408 261-6631 "Free Software For The Rest Of Us."
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