Stop padlists from being AVs

In order to fix a bug, I need to add new fields to padlists.  But I
cannot easily do that as long as they are AVs.

So I have created a new padlist struct.

This not only allows me to extend the padlist struct with new members
as necessary, but also saves memory, as we now have a three-pointer
struct where before we had a whole SV head (3-4 pointers) + XPVAV (5
pointers).

This will unfortunately break half of CPAN, but the pad API docs
clearly say this:

    NOTE: this function is experimental and may change or be
    removed without notice.

This would have broken B::Debug, but a patch sent upstream has already
been integrated into blead with commit 9d2d23d981.

1 files changed, 1 insertions, 1 deletions

diff --git a/sv.c b/sv.c
index 904f4bd29a..77bb664c02 100644
--- a/sv.c
+++ b/sv.c
@@ -13904,7 +13904,7 @@ Perl_varname(pTHX_ const GV *const gv, const char gvtype, PADOFFSET targ,
 
 	if (!cv || !CvPADLIST(cv))
 	    return NULL;
-	av = MUTABLE_AV((*av_fetch(CvPADLIST(cv), 0, FALSE)));
+	av = *PADLIST_ARRAY(CvPADLIST(cv));
 	sv = *av_fetch(av, targ, FALSE);
 	sv_setsv(name, sv);
     }