`-Wl,-z,now' works and the GNU-IFUNC resolver is called before `main'.

But RTLD_NOW returns handle and GNU-IFUNC gets called only after `dlsym'.
Even if the executable calling dlopen(, RTLD_NOW) uses -Wl,-z,-now.

The first part of the test below is correct:
+ ./mc
f
main

But this part prints:
+ ./mcd
dlsym
f

while I expect:
+ ./mcd
f
dlsym

This behavior determines how the glibc Bug 2328 should be resolved in GDB.


cat >lc.c <<EOH
#include <stdio.h>
static int
fi (int a)
{
  return a + 1;
}
asm (".type f, @gnu_indirect_function");
int (*
f (void)) (int a)
{
  puts ("f");
  return fi;
}
EOH
cat >mc.c <<EOH
#include <stdio.h>
extern int f (int a);
int
main (void)
{
  puts ("main");
  return f (-1);
}
EOH
cat >mcd.c <<EOH
#include <stdio.h>
#include <dlfcn.h>
int
main (void)
{
  void *h = dlopen ("./lc.so", RTLD_NOW);
  puts ("dlsym");
  int (*fp) (int a) = (int (*) (int a)) dlsym (h, "f");
  return fp (-1);
}
EOH
gcc -o lc.so lc.c -Wall -g -shared -fPIC; gcc -o mc mc.c -Wall -g -Wl,-z,now ./lc.so; gcc -o mcd mcd.c -Wall -g -Wl,-z,now -ldl; (set -x; ./mc; ./mcd)