pp.c: Refactor some behaviours into helper functions

These two new helper functions will be useful for sharing behaviour with
upcoming code, when adding OP_MULTIPARAM.

Author: leonerd

pp.c

@@ -7635,6 +7635,23 @@ PP(pp_anonconst)
 }
 
 
+/* Helper function for use during signature argument handling from @_.
+ * Replaces elements in an AV with a new SV cloned from the original value
+ * at each position from startix onwards until endix.
+ */
+#define av_refresh_elements_range(av, startix, endix)  S_av_refresh_elements_range(aTHX_ av, startix, endix)
+STATIC void
+S_av_refresh_elements_range(pTHX_ AV *av, IV startix, IV endix)
+{
+    for(IV ix = startix; ix < endix; ix++) {
+        SV **svp = av_fetch(av, ix, FALSE);
+        SV *newsv = newSVsv_flags(svp ? *svp : &PL_sv_undef,
+                (SV_DO_COW_SVSETSV|SV_NOSTEAL));
+        if(!av_store(av, ix, newsv))
+            SvREFCNT_dec_NN(newsv);
+    }
+}
+
 /* process one subroutine argument - typically when the sub has a signature:
  * introduce PL_curpad[op_targ] and assign to it the value
  *  for $:   (OPf_STACKED ? *sp : $_[N])
@@ -7713,13 +7730,7 @@ PP_wrapped(pp_argelem,
              * to avoid the equivalent of @a = ($a[0]) prematurely freeing
              * elements. See similar code in pp_aassign.
              */
-            for (i = 0; i < argc; i++) {
-                SV **svp = av_fetch(defav, ix + i, FALSE);
-                SV *newsv = newSVsv_flags(svp ? *svp : &PL_sv_undef,
-                                (SV_DO_COW_SVSETSV|SV_NOSTEAL));
-                if (!av_store(defav, ix + i, newsv))
-                    SvREFCNT_dec_NN(newsv);
-            }
+            av_refresh_elements_range(defav, ix, ix + argc);
             av_clear((AV*)targ);
         }
 
@@ -7745,13 +7756,7 @@ PP_wrapped(pp_argelem,
 
         if (SvRMAGICAL(targ) || HvUSEDKEYS((HV*)targ)) {
             /* see "target should usually be empty" comment above */
-            for (i = 0; i < argc; i++) {
-                SV **svp = av_fetch(defav, ix + i, FALSE);
-                SV *newsv = newSVsv_flags(svp ? *svp : &PL_sv_undef,
-                                    (SV_DO_COW_SVSETSV|SV_NOSTEAL));
-                if (!av_store(defav, ix + i, newsv))
-                    SvREFCNT_dec_NN(newsv);
-            }
+            av_refresh_elements_range(defav, ix, ix + argc);
             hv_clear((HV*)targ);
         }
 
@@ -7842,20 +7847,10 @@ S_find_runcv_name(void)
  * signatured subs.
  */
 
-PP(pp_argcheck)
+static void
+S_check_argc(pTHX_ UV argc, UV params, UV opt_params, char slurpy)
 {
-    OP * const o       = PL_op;
-    struct op_argcheck_aux *aux = (struct op_argcheck_aux *)cUNOP_AUXo->op_aux;
-    UV   params        = aux->params;
-    UV   opt_params    = aux->opt_params;
-    char slurpy        = aux->slurpy;
-    AV  *defav         = GvAV(PL_defgv); /* @_ */
-    UV   argc;
-    bool too_few;
-
-    assert(!SvMAGICAL(defav));
-    argc = (UV)(AvFILLp(defav) + 1);
-    too_few = (argc < (params - opt_params));
+    bool too_few = (argc < (params - opt_params));
 
     if (UNLIKELY(too_few || (!slurpy && argc > params)))
 
@@ -7874,6 +7869,18 @@ PP(pp_argcheck)
         /* diag_listed_as: Odd name/value argument for subroutine '%s' */
         Perl_croak_caller("Odd name/value argument for subroutine '%" SVf "'",
                           S_find_runcv_name());
+}
+
+PP(pp_argcheck)
+{
+    OP * const o       = PL_op;
+    struct op_argcheck_aux *aux = (struct op_argcheck_aux *)cUNOP_AUXo->op_aux;
+    AV  *defav         = GvAV(PL_defgv); /* @_ */
+
+    assert(!SvMAGICAL(defav));
+    UV argc = (UV)(AvFILLp(defav) + 1);
+
+    S_check_argc(aTHX_ argc, aux->params, aux->opt_params, aux->slurpy);
 
     return NORMAL;
 }