free up CvPADLIST slot for XSUBs for future use

CvRESERVED is a placeholder, it will be replaced with a sentinal value
from future revised BOOTCHECK API.

CvPADLIST_set was helpful during development of this patch, so keep it
around for now.

PoisonPADLIST's magic value is from PERL_POISON 0xEF pattern. Some
PoisonPADLIST locations will get code from future BOOTCHECK API.

Make padlist_dup a NN function to avoid overhead of calling it for XSUBs
during closing.

Perl_cv_undef_flags's else if (CvISXSUB(&cvbody)) is to avoid whitespace
changes.

Filed as perl [#123059].

1 files changed, 1 insertions, 0 deletions

diff --git a/gv.c b/gv.c
index 04013a522e..7abc6ccacb 100644
--- a/gv.c
+++ b/gv.c
@@ -568,6 +568,7 @@ S_maybe_add_coresub(pTHX_ HV * const stash, GV *gv,
 	GvCVGEN(gv) = 0;
 	CvISXSUB_on(cv);
 	CvXSUB(cv) = core_xsub;
+	PoisonPADLIST(cv);
     }
     CvGV_set(cv, gv); /* This stops new ATTRSUB from setting CvFILE
                          from PL_curcop. */