Fix the "PerlIO require leak". Snag was that clean_objs

autoloaded DESTROY (needing IO) after known layers had
been freed. Postpone layer list free to PerlIO_cleanup,
rather than PerlIO_destruct. Tweak sequence in perl_destruct
so that sv_undef is immortal till layer list is done with it.

p4raw-id: //depot/perlio@16335

1 files changed, 12 insertions, 5 deletions

diff --git a/perlio.c b/perlio.c
index ac355274e1..e80c1f0fbf 100644
--- a/perlio.c
+++ b/perlio.c
@@ -601,10 +601,6 @@ PerlIO_destruct(pTHX)
 	    f++;
 	}
     }
-    PerlIO_list_free(aTHX_ PL_known_layers);
-    PL_known_layers = NULL;
-    PerlIO_list_free(aTHX_ PL_def_layerlist);
-    PL_def_layerlist = NULL;
 }
 
 void
@@ -2071,7 +2067,9 @@ PerlIO_cleanup(pTHX)
 {
     int i;
 #ifdef USE_ITHREADS
-    PerlIO_debug("Cleanup %p\n",aTHX);
+    PerlIO_debug("Cleanup layers for %p\n",aTHX);
+#else
+    PerlIO_debug("Cleanup layers\n");
 #endif
     /* Raise STDIN..STDERR refcount so we don't close them */
     for (i=0; i < 3; i++)
@@ -2080,6 +2078,15 @@ PerlIO_cleanup(pTHX)
     /* Restore STDIN..STDERR refcount */
     for (i=0; i < 3; i++)
 	PerlIOUnix_refcnt_dec(i);
+
+    if (PL_known_layers) {
+	PerlIO_list_free(aTHX_ PL_known_layers);
+	PL_known_layers = NULL;
+    }
+    if(PL_def_layerlist) {
+	PerlIO_list_free(aTHX_ PL_def_layerlist);
+	PL_def_layerlist = NULL;
+    }
 }