Binutils and glibc implemented STT_GNU_IFUNC:
http://groups.google.com/group/generic-abi
A new ifunc attribute can provide user access to this
feature at C language level. Several options:
1. Ifunc attribute with argument:
int foo (
);
__typeof (foo) *
__attribute__ ((ifunc ("foo")))
foo_ifunc (void)
{
<return address of foo_{1,2,3}>
}
foo_ifunc is a dummy place holder which isn't necessary.
2. Ifunc attribute without argument:
void *
__attribute__ ((ifunc))
foo (void)
{
<return address of foo_{1,2,3}>
}
We can't call foo in the same file where foo is defined
since we need a different prototype when calling foo.
3. Ifunc attribute with prototype, but without argument:
int
__attribute__ ((ifunc))
foo (...)
{
<return address of foo_{1,2,3}>
}
We can call foo in the same file. Gcc checks the return value for
foo.
--
Summary: Add a new ifunc attribute
Product: gcc
Version: 4.5.0
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: hjl dot tools at gmail dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40528
