Partially pessimise in-place sorting

[perl5.git] / pp_sort.c

diff --git a/pp_sort.c b/pp_sort.c
index 9e0d64c..e171411 100644 (file)
--- a/pp_sort.c
+++ b/pp_sort.c
@@ -1476,13 +1476,12 @@ PP(pp_sort)
     AV* av = NULL;
     GV *gv;
     CV *cv = NULL;
-    I32 gimme = GIMME_V;
+    U8 gimme = GIMME_V;
     OP* const nextop = PL_op->op_next;
     I32 overloading = 0;
     bool hasargs = FALSE;
     bool copytmps;
     I32 is_xsub = 0;
-    I32 sorting_av = 0;
     const U8 priv = PL_op->op_private;
     const U8 flags = PL_op->op_flags;
     U32 sort_flags = 0;
@@ -1563,34 +1562,31 @@ PP(pp_sort)
        PL_sortcop = NULL;
     }
 
-    /* optimiser converts "@a = sort @a" to "sort \@a";
-     * in case of tied @a, pessimise: push (@a) onto stack, then assign
-     * result back to @a at the end of this function */
+    /* optimiser converts "@a = sort @a" to "sort \@a".  In this case,
+     * push (@a) onto stack, then assign result back to @a at the end of
+     * this function */
     if (priv & OPpSORT_INPLACE) {
        assert( MARK+1 == SP && *SP && SvTYPE(*SP) == SVt_PVAV);
        (void)POPMARK; /* remove mark associated with ex-OP_AASSIGN */
        av = MUTABLE_AV((*SP));
+        if (SvREADONLY(av))
+            Perl_croak_no_modify();
        max = AvFILL(av) + 1;
+        MEXTEND(SP, max);
        if (SvMAGICAL(av)) {
-           MEXTEND(SP, max);
            for (i=0; i < max; i++) {
                SV **svp = av_fetch(av, i, FALSE);
                *SP++ = (svp) ? *svp : NULL;
            }
-           SP--;
-           p1 = p2 = SP - (max-1);
        }
-       else {
-           if (SvREADONLY(av))
-               Perl_croak_no_modify();
-           else
-           {
-               SvREADONLY_on(av);
-               save_pushptr((void *)av, SAVEt_READONLY_OFF);
-           }
-           p1 = p2 = AvARRAY(av);
-           sorting_av = 1;
+        else {
+            SV **svp = AvARRAY(av);
+            assert(svp || max == 0);
+           for (i = 0; i < max; i++)
+                *SP++ = *svp++;
        }
+        SP--;
+        p1 = p2 = SP - (max-1);
     }
     else {
        p2 = MARK+1;
@@ -1600,7 +1596,7 @@ PP(pp_sort)
     /* shuffle stack down, removing optional initial cv (p1!=p2), plus
      * any nulls; also stringify or converting to integer or number as
      * required any args */
-    copytmps = !sorting_av && PL_sortcop;
+    copytmps = PL_sortcop;
     for (i=max; i > 0 ; i--) {
        if ((*p1 = *p2++)) {                    /* Weed out nulls. */
            if (copytmps && SvPADTMP(*p1)) {
@@ -1633,9 +1629,6 @@ PP(pp_sort)
        else
            max--;
     }
-    if (sorting_av)
-       AvFILLp(av) = max-1;
-
     if (max > 1) {
        SV **start;
        if (PL_sortcop) {
@@ -1668,10 +1661,10 @@ PP(pp_sort)
            }
 
             gimme = G_SCALAR;
-           PUSHBLOCK(cx, CXt_NULL, PL_stack_base);
+           cx = cx_pushblock(CXt_NULL, gimme, PL_stack_base, old_savestack_ix);
            if (!(flags & OPf_SPECIAL)) {
                cx->cx_type = CXt_SUB|CXp_MULTICALL;
-               PUSHSUB(cx);
+               cx_pushsub(cx, cv, NULL, hasargs);
                if (!is_xsub) {
                    PADLIST * const padlist = CvPADLIST(cv);
 
@@ -1689,7 +1682,6 @@ PP(pp_sort)
 
                }
            }
-            cx->blk_oldsaveix = old_savestack_ix;
 
            start = p1 - max;
            sortsvp(aTHX_ start, max,
@@ -1704,20 +1696,20 @@ PP(pp_sort)
             CX_LEAVE_SCOPE(cx);
            if (!(flags & OPf_SPECIAL)) {
                 assert(CxTYPE(cx) == CXt_SUB);
-                CX_POPSUB(cx);
+                cx_popsub(cx);
            }
             else
                 assert(CxTYPE(cx) == CXt_NULL);
                 /* there isn't a POPNULL ! */
 
-           CX_POPBLOCK(cx);
+           cx_popblock(cx);
             CX_POP(cx);
            POPSTACK;
            CATCH_SET(oldcatch);
        }
        else {
            MEXTEND(SP, 20);    /* Can't afford stack realloc on signal. */
-           start = sorting_av ? AvARRAY(av) : ORIGMARK+1;
+           start = ORIGMARK+1;
            sortsvp(aTHX_ start, max,
                    (priv & OPpSORT_NUMERIC)
                        ? ( ( ( priv & OPpSORT_INTEGER) || all_SIVs)
@@ -1743,27 +1735,45 @@ PP(pp_sort)
            }
        }
     }
-    if (sorting_av)
-       SvREADONLY_off(av);
-    else if (av && !sorting_av) {
-       /* simulate pp_aassign of tied AV */
-       SV** const base = MARK+1;
-       for (i=0; i < max; i++) {
-           base[i] = newSVsv(base[i]);
-       }
-       av_clear(av);
-       av_extend(av, max);
-       for (i=0; i < max; i++) {
-           SV * const sv = base[i];
-           SV ** const didstore = av_store(av, i, sv);
-           if (SvSMAGICAL(sv))
-               mg_set(sv);
-           if (!didstore)
-               sv_2mortal(sv);
-       }
+
+    if (av) {
+        /* copy back result to the array */
+        SV** const base = MARK+1;
+        if (SvMAGICAL(av)) {
+            for (i = 0; i < max; i++)
+                base[i] = newSVsv(base[i]);
+            av_clear(av);
+            av_extend(av, max);
+            for (i=0; i < max; i++) {
+                SV * const sv = base[i];
+                SV ** const didstore = av_store(av, i, sv);
+                if (SvSMAGICAL(sv))
+                    mg_set(sv);
+                if (!didstore)
+                    sv_2mortal(sv);
+            }
+        }
+        else {
+            /* the elements of av are likely to be the same as the
+             * (non-refcounted) elements on the stack, just in a different
+             * order. However, its possible that someone's messed with av
+             * in the meantime. So bump and unbump the relevant refcounts
+             * first.
+             */
+            for (i = 0; i < max; i++)
+                SvREFCNT_inc_void(base[i]);
+            av_clear(av);
+            if (max > 0) {
+                av_extend(av, max);
+                Copy(base, AvARRAY(av), max, SV*);
+            }
+            AvFILLp(av) = max - 1;
+            AvREIFY_off(av);
+            AvREAL_on(av);
+        }
     }
     LEAVE;
-    PL_stack_sp = ORIGMARK + (sorting_av ? 0 : max);
+    PL_stack_sp = ORIGMARK +  max;
     return nextop;
 }