Used pad name lists for pad ids

I added pad IDs so that a pad could record which pad it closes over,
to avoid problems with closures closing over the wrong pad, resulting
in crashes or bizarre copies.  These pad IDs were shared between
clones of the same pad.

In commit 9ef8d56, for efficiency I made clones of the same closure
share the same pad name list.

It has just occurred to be that each padlist containing the same pad
name list also has the same pad ID, so we can just use the pad name
list itself as the ID.

This makes padlists 32 bits smaller and eliminates PL_pad_generation
from the interpreter struct.

1 files changed, 1 insertions, 2 deletions

diff --git a/pad.h b/pad.h
index f65af17a78..26e183ccd8 100644
--- a/pad.h
+++ b/pad.h
@@ -31,8 +31,7 @@ typedef U64TYPE PADOFFSET;
 struct padlist {
     SSize_t	xpadl_max;	/* max index for which array has space */
     PAD **	xpadl_alloc;	/* pointer to beginning of array of AVs */
-    U32		xpadl_id;	/* Semi-unique ID, shared between clones */
-    U32		xpadl_outid;	/* ID of outer pad */
+    PADNAMELIST*xpadl_outid;	/* Padnamelist of outer pad; used as ID */
 };