With -DPERL_DEBUG_READONLY_OPS, changing a slab refcnt shouldn't make it r/w.

Perl_op_refcnt_inc() and Perl_op_refcnt_dec() now both take care to leave the
slab in the same state as they found it. Previously both would
unconditionally make the slab read-write.

diff --git a/op.c b/op.c
index 7305ab5..1af16f7 100644 (file)
--- a/op.c
+++ b/op.c
@@ -406,8 +406,14 @@ OP *
 Perl_op_refcnt_inc(pTHX_ OP *o)
 {
     if(o) {
-       Slab_to_rw(o);
-       ++o->op_targ;
+        OPSLAB *const slab = o->op_slabbed ? OpSLAB(o) : NULL;
+        if (slab && slab->opslab_readonly) {
+            Slab_to_rw(o);
+            ++o->op_targ;
+            Slab_to_ro(slab);
+        } else {
+            ++o->op_targ;
+        }
     }
     return o;
 
@@ -416,9 +422,19 @@ Perl_op_refcnt_inc(pTHX_ OP *o)
 PADOFFSET
 Perl_op_refcnt_dec(pTHX_ OP *o)
 {
+    PADOFFSET result;
+    OPSLAB *const slab = o->op_slabbed ? OpSLAB(o) : NULL;
+
     PERL_ARGS_ASSERT_OP_REFCNT_DEC;
-    Slab_to_rw(o);
-    return --o->op_targ;
+
+    if (slab && slab->opslab_readonly) {
+        Slab_to_rw(o);
+        result = --o->op_targ;
+        Slab_to_ro(slab);
+    } else {
+        result = --o->op_targ;
+    }
+    return result;
 }
 #endif
 /*