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Re: weakref and static
On Dec 11, 2005, Alexandre Oliva <aoliva@redhat.com> wrote:
> On Dec 1, 2005, gkeating@apple.com (Geoffrey Keating) wrote:
>> The easiest solution to this is to require that weakrefs must be
>> 'static', because the name that they define is not visible outside
>> this translation unit.
> While this is true, not all properties of static names hold for
> weakrefs. If the name they refer to is not itself static, none of the
> local-binding analysis properties will apply correctly if the wekaref
> is marked as static. I felt it was safer to keep it extern.
As evidenced by the following testcase:
extern int i;
static int j __attribute__((weakref("i")));
int f() {
return j;
}
whose output assembly for AMD64 is:
[...]
movl j(%rip), %eax
[...]
.weakref j,i
[...]
So you see, j(%rip) is only valid when a symbol is known to be defined
in the same loadable module, but this is definitely not known for the
testcase above.
I thus propose your change to be reverted, and request you to explain
what you were trying to fix with this patch so that I can try to do
something about it.
--
Alexandre Oliva http://www.lsd.ic.unicamp.br/~oliva/
Red Hat Compiler Engineer aoliva@{redhat.com, gcc.gnu.org}
Free Software Evangelist oliva@{lsd.ic.unicamp.br, gnu.org}