regcomp.c: Avoid unnecessary runtime fold checking

[perl5.git] / hv.c

diff --git a/hv.c b/hv.c
index 48f21e9..f166968 100644 (file)
--- a/hv.c
+++ b/hv.c
@@ -19,10 +19,10 @@
 /* 
 =head1 Hash Manipulation Functions
 
-A HV structure represents a Perl hash. It consists mainly of an array
-of pointers, each of which points to a linked list of HE structures. The
+A HV structure represents a Perl hash.  It consists mainly of an array
+of pointers, each of which points to a linked list of HE structures.  The
 array is indexed by the hash function of the key, so each linked list
-represents all the hash entries with the same hash value. Each HE contains
+represents all the hash entries with the same hash value.  Each HE contains
 a pointer to the actual value, plus a pointer to a HEK structure which
 holds the key and hash value.
 
@@ -285,7 +285,8 @@ information on how to use this function on tied hashes.
 
 =for apidoc hv_exists_ent
 
-Returns a boolean indicating whether the specified hash key exists. C<hash>
+Returns a boolean indicating whether
+the specified hash key exists.  C<hash>
 can be a valid precomputed hash value, or 0 to ask for it to be
 computed.
 
@@ -1545,7 +1546,10 @@ Perl_hv_delayfree_ent(pTHX_ HV *hv, register HE *entry)
 =for apidoc hv_clear
 
 Frees the all the elements of a hash, leaving it empty.
-The XS equivalent of %hash = (). See also L</hv_undef>.
+The XS equivalent of C<%hash = ()>.  See also L</hv_undef>.
+
+If any destructors are triggered as a result, the hv itself may
+be freed.
 
 =cut
 */
@@ -1562,6 +1566,8 @@ Perl_hv_clear(pTHX_ HV *hv)
 
     xhv = (XPVHV*)SvANY(hv);
 
+    ENTER;
+    SAVEFREESV(SvREFCNT_inc_simple_NN(hv));
     if (SvREADONLY(hv) && HvARRAY(hv) != NULL) {
        /* restricted hash: convert all keys to placeholders */
        STRLEN i;
@@ -1599,6 +1605,7 @@ Perl_hv_clear(pTHX_ HV *hv)
             mro_isa_changed_in(hv);
        HvEITER_set(hv, NULL);
     }
+    LEAVE;
 }
 
 /*
@@ -1759,10 +1766,14 @@ Perl_hfree_next_entry(pTHX_ HV *hv, STRLEN *indexp)
 /*
 =for apidoc hv_undef
 
-Undefines the hash.  The XS equivalent of undef(%hash).
+Undefines the hash.  The XS equivalent of C<undef(%hash)>.
 
 As well as freeing all the elements of the hash (like hv_clear()), this
 also frees any auxiliary data and storage associated with the hash.
+
+If any destructors are triggered as a result, the hv itself may
+be freed.
+
 See also L</hv_clear>.
 
 =cut
@@ -1774,6 +1785,7 @@ Perl_hv_undef_flags(pTHX_ HV *hv, U32 flags)
     dVAR;
     register XPVHV* xhv;
     const char *name;
+    const bool save = !!SvREFCNT(hv);
 
     if (!hv)
        return;
@@ -1798,6 +1810,10 @@ Perl_hv_undef_flags(pTHX_ HV *hv, U32 flags)
                            );
        hv_name_set(hv, NULL, 0, 0);
     }
+    if (save) {
+       ENTER;
+       SAVEFREESV(SvREFCNT_inc_simple_NN(hv));
+    }
     hfreeentries(hv);
     if (SvOOK(hv)) {
       struct xpvhv_aux * const aux = HvAUX(hv);
@@ -1851,6 +1867,7 @@ Perl_hv_undef_flags(pTHX_ HV *hv, U32 flags)
 
     if (SvRMAGICAL(hv))
        mg_clear(MUTABLE_SV(hv));
+    if (save) LEAVE;
 }
 
 /*
@@ -2120,7 +2137,7 @@ hek_eq_pvn_flags(pTHX_ const HEK *hek, const char* pv, const I32 pvlen, const U3
 /*
 =for apidoc hv_ename_add
 
-Adds a name to a stash's internal list of effective names. See
+Adds a name to a stash's internal list of effective names.  See
 C<hv_ename_delete>.
 
 This is called when a stash is assigned to a new location in the symbol
@@ -2181,7 +2198,7 @@ Perl_hv_ename_add(pTHX_ HV *hv, const char *name, U32 len, U32 flags)
 /*
 =for apidoc hv_ename_delete
 
-Removes a name from a stash's internal list of effective names. If this is
+Removes a name from a stash's internal list of effective names.  If this is
 the name returned by C<HvENAME>, then another name in the list will take
 its place (C<HvENAME> will use it).
 
@@ -2306,7 +2323,7 @@ The C<flags> value will normally be zero; if HV_ITERNEXT_WANTPLACEHOLDERS is
 set the placeholders keys (for restricted hashes) will be returned in addition
 to normal keys. By default placeholders are automatically skipped over.
 Currently a placeholder is implemented with a value that is
-C<&Perl_sv_placeholder>. Note that the implementation of placeholders and
+C<&PL_sv_placeholder>.  Note that the implementation of placeholders and
 restricted hashes may change, and the implementation currently is
 insufficiently abstracted for any change to be tidy.