I'm amazed that no one else mentioned the B module to you. All your scalar references will return the REFCNT number from the referenced scalar. I provided an example - this is a dirt easy task.

use B 'svref_2object';
my $something = "this is tadman's cached data";
my $something_obj = svref_2object(\$something);
my $something_refcnt = $something_obj->REFCNT;
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__SIG__
use B;
printf "You are here %08x\n", unpack "L!", unpack "P4", pack
  "L!", B::svref_2object(sub{})->OUTSIDE;
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