refcounted_he_(new|fetch)_pvn: Don't roll-own code

doio.c

@@ -2215,35 +2215,23 @@ Perl_do_print(pTHX_ SV *sv, PerlIO *fp)
         STRLEN len;
         /* Do this first to trigger any overloading.  */
         const char *tmps = SvPV_const(sv, len);
-        U8 *tmpbuf = NULL;
         bool happy = TRUE;
 
         if (PerlIO_isutf8(fp)) { /* If the stream is utf8 ... */
             if (!SvUTF8(sv)) {	/* Convert to utf8 if necessary */
                 /* We don't modify the original scalar.  */
-                tmpbuf = bytes_to_utf8((const U8*) tmps, &len);
-                tmps = (char *) tmpbuf;
+                tmps = (char *) bytes_to_utf8((const U8*) tmps, &len);
+                SAVEFREEPV(tmps);
             }
             else if (ckWARN4_d(WARN_UTF8, WARN_SURROGATE, WARN_NON_UNICODE, WARN_NONCHAR)) {
                 (void) check_utf8_print((const U8*) tmps, len);
             }
         } /* else stream isn't utf8 */
         else if (DO_UTF8(sv)) { /* But if is utf8 internally, attempt to
                                    convert to bytes */
-            STRLEN tmplen = len;
-            bool utf8 = TRUE;
-            U8 * const result = bytes_from_utf8((const U8*) tmps, &tmplen, &utf8);
-            if (!utf8) {
-
-                /* Here, succeeded in downgrading from utf8.  Set up to below
-                 * output the converted value */
-                tmpbuf = result;
-                tmps = (char *) tmpbuf;
-                len = tmplen;
-            }
-            else {  /* Non-utf8 output stream, but string only representable in
-                       utf8 */
-                assert((char *)result == tmps);
+            if (! utf8_to_bytes_temp_pv((const U8**) &tmps, &len)) {
+                /* Non-utf8 output stream, but string only representable in
+                   utf8 */
                 Perl_ck_warner_d(aTHX_ packWARN(WARN_UTF8),
                                  "Wide character in %s",
                                    PL_op ? OP_DESC(PL_op) : "print"
@@ -2261,7 +2249,6 @@ Perl_do_print(pTHX_ SV *sv, PerlIO *fp)
          * io the write failure can be delayed until the flush/close. --jhi */
         if (len && (PerlIO_write(fp,tmps,len) == 0))
             happy = FALSE;
-        Safefree(tmpbuf);
         return happy ? !PerlIO_error(fp) : FALSE;
     }
 }

embed.fnc

@@ -3697,6 +3697,20 @@ CDbdp	|UV	|utf8n_to_uvuni |NN const U8 *s 			\
 				|U32 flags
 Adpx	|U8 *	|utf8_to_bytes	|NN U8 *s				\
 				|NN STRLEN *lenp
+Cp	|bool	|utf8_to_bytes_ |NN U8 **s_ptr				\
+				|NN STRLEN *lenp			\
+				|NN U8 **free_me			\
+				|Perl_utf8_to_bytes_arg result_as
+Admp	|bool	|utf8_to_bytes_new_pv					\
+				|NN U8 const **s_ptr			\
+				|NN STRLEN *lenp			\
+				|NN U8 *free_me
+Admp	|bool	|utf8_to_bytes_overwrite				\
+				|NN U8 **s_ptr				\
+				|NN STRLEN *lenp
+Admp	|bool	|utf8_to_bytes_temp_pv					\
+				|NN U8 const **s_ptr			\
+				|NN STRLEN *lenp
 EMXp	|U8 *	|utf16_to_utf8	|NN U8 *p				\
 				|NN U8 *d				\
 				|Size_t bytelen 			\

embed.h

@@ -797,6 +797,10 @@
 # define utf8_hop_safe                          Perl_utf8_hop_safe
 # define utf8_length(a,b)                       Perl_utf8_length(aTHX_ a,b)
 # define utf8_to_bytes(a,b)                     Perl_utf8_to_bytes(aTHX_ a,b)
+# define utf8_to_bytes_(a,b,c,d)                Perl_utf8_to_bytes_(aTHX_ a,b,c,d)
+# define utf8_to_bytes_new_pv(a,b,c)            Perl_utf8_to_bytes_new_pv(aTHX,a,b,c)
+# define utf8_to_bytes_overwrite(a,b)           Perl_utf8_to_bytes_overwrite(aTHX,a,b)
+# define utf8_to_bytes_temp_pv(a,b)             Perl_utf8_to_bytes_temp_pv(aTHX,a,b)
 # define utf8_to_uvchr_buf_helper(a,b,c)        Perl_utf8_to_uvchr_buf_helper(aTHX_ a,b,c)
 # define utf8n_to_uvchr_msgs                    Perl_utf8n_to_uvchr_msgs
 # define uvchr_to_utf8(a,b)                     Perl_uvchr_to_utf8(aTHX,a,b)