X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=gv.c;h=39f4b6ad932372e57f45a74e3b08329c74c372a7;hb=0c5a913da36d66becd2cf3a592f69c87a3e9b51b;hp=b68f2128604e4f67b5f4d9f6a860934b2cddf9a8;hpb=392db708ea3e6ba973f656d139373678acbb4e63;p=p5sagit%2Fp5-mst-13.2.git

diff --git a/gv.c b/gv.c
index b68f212..39f4b6a 100644
--- a/gv.c
+++ b/gv.c
@@ -1,7 +1,7 @@
 /*    gv.c
  *
  *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
- *    2000, 2001, 2002, 2003, 2004, by Larry Wall and others
+ *    2000, 2001, 2002, 2003, 2004, 2005, by Larry Wall and others
  *
  *    You may distribute under the terms of either the GNU General Public
  *    License or the Artistic License, as specified in the README file.
@@ -34,6 +34,22 @@ Perl stores its global variables.
 #define PERL_IN_GV_C
 #include "perl.h"
 
+static const char S_autoload[] = "AUTOLOAD";
+static const STRLEN S_autolen = sizeof(S_autoload)-1;
+
+
+#ifdef PERL_DONT_CREATE_GVSV
+GV *
+Perl_gv_SVadd(pTHX_ GV *gv)
+{
+    if (!gv || SvTYPE((SV*)gv) != SVt_PVGV)
+	Perl_croak(aTHX_ "Bad symbol for scalar");
+    if (!GvSV(gv))
+	GvSV(gv) = NEWSV(72,0);
+    return gv;
+}
+#endif
+
 GV *
 Perl_gv_AVadd(pTHX_ register GV *gv)
 {
@@ -89,11 +105,15 @@ Perl_gv_fetchfile(pTHX_ const char *name)
     /* This is where the debugger's %{"::_<$filename"} hash is created */
     tmpbuf[0] = '_';
     tmpbuf[1] = '<';
-    strcpy(tmpbuf + 2, name);
+    memcpy(tmpbuf + 2, name, tmplen - 1);
     gv = *(GV**)hv_fetch(PL_defstash, tmpbuf, tmplen, TRUE);
     if (!isGV(gv)) {
 	gv_init(gv, PL_defstash, tmpbuf, tmplen, FALSE);
-	sv_setpv(GvSV(gv), name);
+#ifdef PERL_DONT_CREATE_GVSV
+	GvSV(gv) = newSVpvn(name, tmplen - 2);
+#else
+	sv_setpvn(GvSV(gv), name, tmplen - 2);
+#endif
 	if (PERLDB_LINE)
 	    hv_magic(GvHVn(gv_AVadd(gv)), Nullgv, PERL_MAGIC_dbfile);
     }
@@ -105,28 +125,37 @@ Perl_gv_fetchfile(pTHX_ const char *name)
 void
 Perl_gv_init(pTHX_ GV *gv, HV *stash, const char *name, STRLEN len, int multi)
 {
+    dVAR;
     register GP *gp;
-    bool doproto = SvTYPE(gv) > SVt_NULL;
-    char *proto = (doproto && SvPOK(gv)) ? SvPVX(gv) : NULL;
+    const bool doproto = SvTYPE(gv) > SVt_NULL;
+    const char * const proto = (doproto && SvPOK(gv)) ? SvPVX_const(gv) : NULL;
 
     sv_upgrade((SV*)gv, SVt_PVGV);
     if (SvLEN(gv)) {
 	if (proto) {
-	    SvPVX(gv) = NULL;
-	    SvLEN(gv) = 0;
+	    SvPV_set(gv, NULL);
+	    SvLEN_set(gv, 0);
 	    SvPOK_off(gv);
 	} else
-	    Safefree(SvPVX(gv));
+	    Safefree(SvPVX_mutable(gv));
     }
     Newz(602, gp, 1, GP);
     GvGP(gv) = gp_ref(gp);
+#ifdef PERL_DONT_CREATE_GVSV
+    GvSV(gv) = 0;
+#else
     GvSV(gv) = NEWSV(72,0);
+#endif
     GvLINE(gv) = CopLINE(PL_curcop);
-    GvFILE(gv) = CopFILE(PL_curcop) ? CopFILE(PL_curcop) : "";
+    /* XXX Ideally this cast would be replaced with a change to const char*
+       in the struct.  */
+    GvFILE(gv) = CopFILE(PL_curcop) ? CopFILE(PL_curcop) : (char *) "";
     GvCVGEN(gv) = 0;
     GvEGV(gv) = gv;
     sv_magic((SV*)gv, (SV*)gv, PERL_MAGIC_glob, Nullch, 0);
-    GvSTASH(gv) = (HV*)SvREFCNT_inc(stash);
+    GvSTASH(gv) = stash;
+    if (stash)
+	Perl_sv_add_backref(aTHX_ (SV*)stash, (SV*)gv);
     GvNAME(gv) = savepvn(name, len);
     GvNAMELEN(gv) = len;
     if (multi || doproto)              /* doproto means it _was_ mentioned */
@@ -163,6 +192,14 @@ S_gv_init_sv(pTHX_ GV *gv, I32 sv_type)
     case SVt_PVHV:
 	(void)GvHVn(gv);
 	break;
+#ifdef PERL_DONT_CREATE_GVSV
+    case SVt_NULL:
+    case SVt_PVCV:
+    case SVt_PVFM:
+	break;
+    default:
+	(void)GvSVn(gv);
+#endif
     }
 }
 
@@ -195,6 +232,7 @@ Perl_gv_fetchmeth(pTHX_ HV *stash, const char *name, STRLEN len, I32 level)
     GV* gv;
     GV** gvp;
     CV* cv;
+    const char *hvname;
 
     /* UNIVERSAL methods should be callable without a stash */
     if (!stash) {
@@ -203,15 +241,16 @@ Perl_gv_fetchmeth(pTHX_ HV *stash, const char *name, STRLEN len, I32 level)
 	    return 0;
     }
 
-    if (!HvNAME(stash))
+    hvname = HvNAME_get(stash);
+    if (!hvname)
       Perl_croak(aTHX_
 		 "Can't use anonymous symbol table for method lookup");
 
     if ((level > 100) || (level < -100))
 	Perl_croak(aTHX_ "Recursive inheritance detected while looking for method '%s' in package '%s'",
-	      name, HvNAME(stash));
+	      name, hvname);
 
-    DEBUG_o( Perl_deb(aTHX_ "Looking for method %s in package %s\n",name,HvNAME(stash)) );
+    DEBUG_o( Perl_deb(aTHX_ "Looking for method %s in package %s\n",name,hvname) );
 
     gvp = (GV**)hv_fetch(stash, name, len, (level >= 0));
     if (!gvp)
@@ -238,19 +277,18 @@ Perl_gv_fetchmeth(pTHX_ HV *stash, const char *name, STRLEN len, I32 level)
 
     /* create and re-create @.*::SUPER::ISA on demand */
     if (!av || !SvMAGIC(av)) {
-	char* packname = HvNAME(stash);
-	STRLEN packlen = strlen(packname);
+	STRLEN packlen = HvNAMELEN_get(stash);
 
-	if (packlen >= 7 && strEQ(packname + packlen - 7, "::SUPER")) {
+	if (packlen >= 7 && strEQ(hvname + packlen - 7, "::SUPER")) {
 	    HV* basestash;
 
 	    packlen -= 7;
-	    basestash = gv_stashpvn(packname, packlen, TRUE);
+	    basestash = gv_stashpvn(hvname, packlen, TRUE);
 	    gvp = (GV**)hv_fetch(basestash, "ISA", 3, FALSE);
 	    if (gvp && (gv = *gvp) != (GV*)&PL_sv_undef && (av = GvAV(gv))) {
 		gvp = (GV**)hv_fetch(stash, "ISA", 3, TRUE);
 		if (!gvp || !(gv = *gvp))
-		    Perl_croak(aTHX_ "Cannot create %s::ISA", HvNAME(stash));
+		    Perl_croak(aTHX_ "Cannot create %s::ISA", hvname);
 		if (SvTYPE(gv) != SVt_PVGV)
 		    gv_init(gv, stash, "ISA", 3, TRUE);
 		SvREFCNT_dec(GvAV(gv));
@@ -269,7 +307,7 @@ Perl_gv_fetchmeth(pTHX_ HV *stash, const char *name, STRLEN len, I32 level)
 	    if (!basestash) {
 		if (ckWARN(WARN_MISC))
 		    Perl_warner(aTHX_ packWARN(WARN_MISC), "Can't locate package %"SVf" for @%s::ISA",
-			sv, HvNAME(stash));
+			sv, hvname);
 		continue;
 	    }
 	    gv = gv_fetchmeth(basestash, name, len,
@@ -335,16 +373,14 @@ Perl_gv_fetchmeth_autoload(pTHX_ HV *stash, const char *name, STRLEN len, I32 le
     GV *gv = gv_fetchmeth(stash, name, len, level);
 
     if (!gv) {
-	char autoload[] = "AUTOLOAD";
-	STRLEN autolen = sizeof(autoload)-1;
 	CV *cv;
 	GV **gvp;
 
 	if (!stash)
 	    return Nullgv;	/* UNIVERSAL::AUTOLOAD could cause trouble */
-	if (len == autolen && strnEQ(name, autoload, autolen))
+	if (len == S_autolen && strnEQ(name, S_autoload, S_autolen))
 	    return Nullgv;
-	if (!(gv = gv_fetchmeth(stash, autoload, autolen, FALSE)))
+	if (!(gv = gv_fetchmeth(stash, S_autoload, S_autolen, FALSE)))
 	    return Nullgv;
 	cv = GvCV(gv);
 	if (!(CvROOT(cv) || CvXSUB(cv)))
@@ -420,7 +456,7 @@ Perl_gv_fetchmethod_autoload(pTHX_ HV *stash, const char *name, I32 autoload)
 	    nsplit = ++nend;
     }
     if (nsplit) {
-	const char *origname = name;
+	const char * const origname = name;
 	name = nsplit + 1;
 	if (*nsplit == ':')
 	    --nsplit;
@@ -429,9 +465,9 @@ Perl_gv_fetchmethod_autoload(pTHX_ HV *stash, const char *name, I32 autoload)
 	    SV *tmpstr = sv_2mortal(Perl_newSVpvf(aTHX_ "%s::SUPER",
 						  CopSTASHPV(PL_curcop)));
 	    /* __PACKAGE__::SUPER stash should be autovivified */
-	    stash = gv_stashpvn(SvPVX(tmpstr), SvCUR(tmpstr), TRUE);
+	    stash = gv_stashpvn(SvPVX_const(tmpstr), SvCUR(tmpstr), TRUE);
 	    DEBUG_o( Perl_deb(aTHX_ "Treating %s as %s::%s\n",
-			 origname, HvNAME(stash), name) );
+			 origname, HvNAME_get(stash), name) );
 	}
 	else {
             /* don't autovifify if ->NoSuchStash::method */
@@ -455,7 +491,7 @@ Perl_gv_fetchmethod_autoload(pTHX_ HV *stash, const char *name, I32 autoload)
 	    gv = gv_autoload4(ostash, name, nend - name, TRUE);
     }
     else if (autoload) {
-	CV* cv = GvCV(gv);
+	CV* const cv = GvCV(gv);
 	if (!CvROOT(cv) && !CvXSUB(cv)) {
 	    GV* stubgv;
 	    GV* autogv;
@@ -480,27 +516,28 @@ Perl_gv_fetchmethod_autoload(pTHX_ HV *stash, const char *name, I32 autoload)
 GV*
 Perl_gv_autoload4(pTHX_ HV *stash, const char *name, STRLEN len, I32 method)
 {
-    char autoload[] = "AUTOLOAD";
-    STRLEN autolen = sizeof(autoload)-1;
+    dVAR;
     GV* gv;
     CV* cv;
     HV* varstash;
     GV* vargv;
     SV* varsv;
-    char *packname = "";
+    const char *packname = "";
+    STRLEN packname_len;
 
-    if (len == autolen && strnEQ(name, autoload, autolen))
+    if (len == S_autolen && strnEQ(name, S_autoload, S_autolen))
 	return Nullgv;
     if (stash) {
 	if (SvTYPE(stash) < SVt_PVHV) {
-	    packname = SvPV_nolen((SV*)stash);
+	    packname = SvPV_const((SV*)stash, packname_len);
 	    stash = Nullhv;
 	}
 	else {
-	    packname = HvNAME(stash);
+	    packname = HvNAME_get(stash);
+	    packname_len = HvNAMELEN_get(stash);
 	}
     }
-    if (!(gv = gv_fetchmeth(stash, autoload, autolen, FALSE)))
+    if (!(gv = gv_fetchmeth(stash, S_autoload, S_autolen, FALSE)))
 	return Nullgv;
     cv = GvCV(gv);
 
@@ -523,8 +560,8 @@ Perl_gv_autoload4(pTHX_ HV *stash, const char *name, STRLEN len, I32 method)
          * pass along the same data via some unused fields in the CV
          */
         CvSTASH(cv) = stash;
-        SvPVX(cv) = (char *)name; /* cast to lose constness warning */
-        SvCUR(cv) = len;
+        SvPV_set(cv, (char *)name); /* cast to lose constness warning */
+        SvCUR_set(cv, len);
         return gv;
     }
 
@@ -535,14 +572,18 @@ Perl_gv_autoload4(pTHX_ HV *stash, const char *name, STRLEN len, I32 method)
      * original package to look up $AUTOLOAD.
      */
     varstash = GvSTASH(CvGV(cv));
-    vargv = *(GV**)hv_fetch(varstash, autoload, autolen, TRUE);
+    vargv = *(GV**)hv_fetch(varstash, S_autoload, S_autolen, TRUE);
     ENTER;
 
-    if (!isGV(vargv))
-	gv_init(vargv, varstash, autoload, autolen, FALSE);
+    if (!isGV(vargv)) {
+	gv_init(vargv, varstash, S_autoload, S_autolen, FALSE);
+#ifdef PERL_DONT_CREATE_GVSV
+	GvSV(vargv) = NEWSV(72,0);
+#endif
+    }
     LEAVE;
-    varsv = GvSV(vargv);
-    sv_setpv(varsv, packname);
+    varsv = GvSVn(vargv);
+    sv_setpvn(varsv, packname, packname_len);
     sv_catpvn(varsv, "::", 2);
     sv_catpvn(varsv, name, len);
     SvTAINTED_off(varsv);
@@ -555,9 +596,10 @@ Perl_gv_autoload4(pTHX_ HV *stash, const char *name, STRLEN len, I32 method)
 STATIC void
 S_require_errno(pTHX_ GV *gv)
 {
+    dVAR;
     HV* stash = gv_stashpvn("Errno",5,FALSE);
 
-    if (!stash || !(gv_fetchmethod(stash, "TIEHASH"))) { 
+    if (!stash || !(gv_fetchmethod(stash, "TIEHASH"))) {
 	dSP;
 	PUTBACK;
 	ENTER;
@@ -625,8 +667,8 @@ Perl_gv_stashpvn(pTHX_ const char *name, U32 namelen, I32 create)
     if (!GvHV(tmpgv))
 	GvHV(tmpgv) = newHV();
     stash = GvHV(tmpgv);
-    if (!HvNAME(stash))
-	HvNAME(stash) = savepv(name);
+    if (!HvNAME_get(stash))
+	Perl_hv_name_set(aTHX_ stash, name, namelen, 0);
     return stash;
 }
 
@@ -642,15 +684,27 @@ valid UTF-8 string.  See C<gv_stashpv>.
 HV*
 Perl_gv_stashsv(pTHX_ SV *sv, I32 create)
 {
-    register char *ptr;
     STRLEN len;
-    ptr = SvPV(sv,len);
+    const char * const ptr = SvPV_const(sv,len);
     return gv_stashpvn(ptr, len, create);
 }
 
 
 GV *
-Perl_gv_fetchpv(pTHX_ const char *nambeg, I32 add, I32 sv_type)
+Perl_gv_fetchpv(pTHX_ const char *nambeg, I32 add, I32 sv_type) {
+    return gv_fetchpvn_flags(nambeg, strlen(nambeg), add, sv_type);
+}
+
+GV *
+Perl_gv_fetchsv(pTHX_ SV *name, I32 flags, I32 sv_type) {
+    STRLEN len;
+    const char * const nambeg = SvPV_const(name, len);
+    return gv_fetchpvn_flags(nambeg, len, flags | SvUTF8(name), sv_type);
+}
+
+GV *
+Perl_gv_fetchpvn_flags(pTHX_ const char *nambeg, STRLEN full_len, I32 flags,
+		       I32 sv_type)
 {
     register const char *name = nambeg;
     register GV *gv = 0;
@@ -658,6 +712,8 @@ Perl_gv_fetchpv(pTHX_ const char *nambeg, I32 add, I32 sv_type)
     I32 len;
     register const char *namend;
     HV *stash = 0;
+    const I32 add = flags & ~SVf_UTF8;
+    (void)full_len;
 
     if (*name == '*' && isALPHA(name[1])) /* accidental stringify on a GV? */
 	name++;
@@ -700,8 +756,8 @@ Perl_gv_fetchpv(pTHX_ const char *nambeg, I32 add, I32 sv_type)
 		if (!(stash = GvHV(gv)))
 		    stash = GvHV(gv) = newHV();
 
-		if (!HvNAME(stash))
-		    HvNAME(stash) = savepvn(nambeg, namend - nambeg);
+		if (!HvNAME_get(stash))
+		    Perl_hv_name_set(aTHX_ stash, nambeg, namend - nambeg, 0);
 	    }
 
 	    if (*namend == ':')
@@ -790,7 +846,7 @@ Perl_gv_fetchpv(pTHX_ const char *nambeg, I32 add, I32 sv_type)
 
     if (!stash) {
 	if (add) {
-	    register SV *err = Perl_mess(aTHX_
+	    SV * const err = Perl_mess(aTHX_
 		 "Global symbol \"%s%s\" requires explicit package name",
 		 (sv_type == SVt_PV ? "$"
 		  : sv_type == SVt_PVAV ? "@"
@@ -831,19 +887,22 @@ Perl_gv_fetchpv(pTHX_ const char *nambeg, I32 add, I32 sv_type)
     gv_init(gv, stash, name, len, add & GV_ADDMULTI);
     gv_init_sv(gv, sv_type);
 
-    if (isALPHA(name[0]) && ! (isLEXWARN_on ? ckWARN(WARN_ONCE) 
+    if (isALPHA(name[0]) && ! (isLEXWARN_on ? ckWARN(WARN_ONCE)
 			                    : (PL_dowarn & G_WARN_ON ) ) )
         GvMULTI_on(gv) ;
 
     /* set up magic where warranted */
     if (len > 1) {
+#ifndef EBCDIC
 	if (*name > 'V' ) {
 	    /* Nothing else to do.
 	       The compiler will probably turn the switch statement into a
 	       branch table. Make sure we avoid even that small overhead for
 	       the common case of lower case variable names.  */
-	} else {
-	    const char *name2 = name + 1;
+	} else
+#endif
+	{
+	    const char * const name2 = name + 1;
 	    switch (*name) {
 	    case 'A':
 		if (strEQ(name2, "RGV")) {
@@ -856,14 +915,14 @@ Perl_gv_fetchpv(pTHX_ const char *nambeg, I32 add, I32 sv_type)
 		break;
 	    case 'I':
 		if (strEQ(name2, "SA")) {
-		    AV* av = GvAVn(gv);
+		    AV* const av = GvAVn(gv);
 		    GvMULTI_on(gv);
 		    sv_magic((SV*)av, (SV*)gv, PERL_MAGIC_isa, Nullch, 0);
 		    /* NOTE: No support for tied ISA */
 		    if ((add & GV_ADDMULTI) && strEQ(nambeg,"AnyDBM_File::ISA")
 			&& AvFILLp(av) == -1)
 			{
-			    char *pname;
+			    const char *pname;
 			    av_push(av, newSVpvn(pname = "NDBM_File",9));
 			    gv_stashpvn(pname, 9, TRUE);
 			    av_push(av, newSVpvn(pname = "DB_File",7));
@@ -879,7 +938,7 @@ Perl_gv_fetchpv(pTHX_ const char *nambeg, I32 add, I32 sv_type)
 		break;
 	    case 'O':
 		if (strEQ(name2, "VERLOAD")) {
-		    HV* hv = GvHVn(gv);
+		    HV* const hv = GvHVn(gv);
 		    GvMULTI_on(gv);
 		    hv_magic(hv, Nullgv, PERL_MAGIC_overload);
 		}
@@ -897,8 +956,7 @@ Perl_gv_fetchpv(pTHX_ const char *nambeg, I32 add, I32 sv_type)
 		    hv = GvHVn(gv);
 		    hv_magic(hv, Nullgv, PERL_MAGIC_sig);
 		    for (i = 1; i < SIG_SIZE; i++) {
-			SV ** init;
-			init = hv_fetch(hv, PL_sig_name[i], strlen(PL_sig_name[i]), 1);
+			SV ** const init = hv_fetch(hv, PL_sig_name[i], strlen(PL_sig_name[i]), 1);
 			if (init)
 			    sv_setsv(*init, &PL_sv_undef);
 			PL_psig_ptr[i] = 0;
@@ -911,6 +969,10 @@ Perl_gv_fetchpv(pTHX_ const char *nambeg, I32 add, I32 sv_type)
 		if (strEQ(name2, "ERSION"))
 		    GvMULTI_on(gv);
 		break;
+            case '\003':        /* $^CHILD_ERROR_NATIVE */
+		if (strEQ(name2, "HILD_ERROR_NATIVE"))
+		    goto magicalize;
+		break;
 	    case '\005':	/* $^ENCODING */
 		if (strEQ(name2, "NCODING"))
 		    goto magicalize;
@@ -923,8 +985,10 @@ Perl_gv_fetchpv(pTHX_ const char *nambeg, I32 add, I32 sv_type)
 		if (strEQ(name2, "AINT"))
 		    goto ro_magicalize;
 		break;
-	    case '\025':	/* $^UNICODE */
-		if (strEQ(name2, "NICODE")) 
+	    case '\025':	/* ${^UNICODE}, ${^UTF8LOCALE} */
+		if (strEQ(name2, "NICODE"))
+		    goto ro_magicalize;
+		if (strEQ(name2, "TF8LOCALE"))
 		    goto ro_magicalize;
 		break;
 	    case '\027':	/* $^WARNING_BITS */
@@ -970,12 +1034,12 @@ Perl_gv_fetchpv(pTHX_ const char *nambeg, I32 add, I32 sv_type)
 	    goto ro_magicalize;
 
 	case ':':
-	    sv_setpv(GvSV(gv),PL_chopset);
+	    sv_setpv(GvSVn(gv),PL_chopset);
 	    goto magicalize;
 
 	case '?':
 #ifdef COMPLEX_STATUS
-	    (void)SvUPGRADE(GvSV(gv), SVt_PVLV);
+	    SvUPGRADE(GvSVn(gv), SVt_PVLV);
 #endif
 	    goto magicalize;
 
@@ -987,7 +1051,7 @@ Perl_gv_fetchpv(pTHX_ const char *nambeg, I32 add, I32 sv_type)
 	       now (rather than going to magicalize)
 	    */
 
-	    sv_magic(GvSV(gv), (SV*)gv, PERL_MAGIC_sv, name, len);
+	    sv_magic(GvSVn(gv), (SV*)gv, PERL_MAGIC_sv, name, len);
 
 	    if (sv_type == SVt_PVHV)
 		require_errno(gv);
@@ -995,28 +1059,24 @@ Perl_gv_fetchpv(pTHX_ const char *nambeg, I32 add, I32 sv_type)
 	    break;
 	case '-':
 	{
-            AV* av = GvAVn(gv);
+	    AV* const av = GvAVn(gv);
             sv_magic((SV*)av, Nullsv, PERL_MAGIC_regdata, Nullch, 0);
 	    SvREADONLY_on(av);
 	    goto magicalize;
 	}
 	case '*':
-	    if (sv_type == SVt_PV && ckWARN2(WARN_DEPRECATED, WARN_SYNTAX))
-		Perl_warner(aTHX_ packWARN2(WARN_DEPRECATED, WARN_SYNTAX),
-			    "$* is no longer supported");
-	    break;
 	case '#':
 	    if (sv_type == SVt_PV && ckWARN2(WARN_DEPRECATED, WARN_SYNTAX))
 		Perl_warner(aTHX_ packWARN2(WARN_DEPRECATED, WARN_SYNTAX),
-			    "Use of $# is deprecated");
-	    goto magicalize;
+			    "$%c is no longer supported", *name);
+	    break;
 	case '|':
-	    sv_setiv(GvSV(gv), (IV)(IoFLAGS(GvIOp(PL_defoutgv)) & IOf_FLUSH) != 0);
+	    sv_setiv(GvSVn(gv), (IV)(IoFLAGS(GvIOp(PL_defoutgv)) & IOf_FLUSH) != 0);
 	    goto magicalize;
 
 	case '+':
 	{
-	    AV* av = GvAVn(gv);
+	    AV* const av = GvAVn(gv);
             sv_magic((SV*)av, (SV*)av, PERL_MAGIC_regdata, Nullch, 0);
 	    SvREADONLY_on(av);
 	    /* FALL THROUGH */
@@ -1032,7 +1092,7 @@ Perl_gv_fetchpv(pTHX_ const char *nambeg, I32 add, I32 sv_type)
 	case '8':
 	case '9':
 	ro_magicalize:
-	    SvREADONLY_on(GvSV(gv));
+	    SvREADONLY_on(GvSVn(gv));
 	    /* FALL THROUGH */
 	case '[':
 	case '^':
@@ -1060,19 +1120,19 @@ Perl_gv_fetchpv(pTHX_ const char *nambeg, I32 add, I32 sv_type)
 	case '\024':	/* $^T */
 	case '\027':	/* $^W */
 	magicalize:
-	    sv_magic(GvSV(gv), (SV*)gv, PERL_MAGIC_sv, name, len);
+	    sv_magic(GvSVn(gv), (SV*)gv, PERL_MAGIC_sv, name, len);
 	    break;
 
 	case '\014':	/* $^L */
-	    sv_setpv(GvSV(gv),"\f");
-	    PL_formfeed = GvSV(gv);
+	    sv_setpvn(GvSVn(gv),"\f",1);
+	    PL_formfeed = GvSVn(gv);
 	    break;
 	case ';':
-	    sv_setpv(GvSV(gv),"\034");
+	    sv_setpvn(GvSVn(gv),"\034",1);
 	    break;
 	case ']':
 	{
-	    SV *sv = GvSV(gv);
+	    SV * const sv = GvSVn(gv);
 	    if (!sv_derived_from(PL_patchlevel, "version"))
 		(void *)upg_version(PL_patchlevel);
 	    GvSV(gv) = vnumify(PL_patchlevel);
@@ -1082,7 +1142,7 @@ Perl_gv_fetchpv(pTHX_ const char *nambeg, I32 add, I32 sv_type)
 	break;
 	case '\026':	/* $^V */
 	{
-	    SV *sv = GvSV(gv);
+	    SV * const sv = GvSVn(gv);
 	    GvSV(gv) = new_version(PL_patchlevel);
 	    SvREADONLY_on(GvSV(gv));
 	    SvREFCNT_dec(sv);
@@ -1094,95 +1154,98 @@ Perl_gv_fetchpv(pTHX_ const char *nambeg, I32 add, I32 sv_type)
 }
 
 void
-Perl_gv_fullname4(pTHX_ SV *sv, GV *gv, const char *prefix, bool keepmain)
+Perl_gv_fullname4(pTHX_ SV *sv, const GV *gv, const char *prefix, bool keepmain)
 {
-    char *name;
-    HV *hv = GvSTASH(gv);
+    const char *name;
+    STRLEN namelen;
+    const HV * const hv = GvSTASH(gv);
     if (!hv) {
 	SvOK_off(sv);
 	return;
     }
     sv_setpv(sv, prefix ? prefix : "");
-    
-    name = HvNAME(hv);
-    if (!name)
+
+    name = HvNAME_get(hv);
+    if (name) {
+	namelen = HvNAMELEN_get(hv);
+    } else {
 	name = "__ANON__";
-	
+	namelen = 8;
+    }
+
     if (keepmain || strNE(name, "main")) {
-	sv_catpv(sv,name);
+	sv_catpvn(sv,name,namelen);
 	sv_catpvn(sv,"::", 2);
     }
     sv_catpvn(sv,GvNAME(gv),GvNAMELEN(gv));
 }
 
 void
-Perl_gv_fullname3(pTHX_ SV *sv, GV *gv, const char *prefix)
+Perl_gv_fullname3(pTHX_ SV *sv, const GV *gv, const char *prefix)
 {
     gv_fullname4(sv, gv, prefix, TRUE);
 }
 
 void
-Perl_gv_efullname4(pTHX_ SV *sv, GV *gv, const char *prefix, bool keepmain)
+Perl_gv_efullname4(pTHX_ SV *sv, const GV *gv, const char *prefix, bool keepmain)
 {
-    GV *egv = GvEGV(gv);
+    const GV *egv = GvEGV(gv);
     if (!egv)
 	egv = gv;
     gv_fullname4(sv, egv, prefix, keepmain);
 }
 
 void
-Perl_gv_efullname3(pTHX_ SV *sv, GV *gv, const char *prefix)
+Perl_gv_efullname3(pTHX_ SV *sv, const GV *gv, const char *prefix)
 {
     gv_efullname4(sv, gv, prefix, TRUE);
 }
 
-/* XXX compatibility with versions <= 5.003. */
+/* compatibility with versions <= 5.003. */
 void
-Perl_gv_fullname(pTHX_ SV *sv, GV *gv)
+Perl_gv_fullname(pTHX_ SV *sv, const GV *gv)
 {
-    gv_fullname3(sv, gv, sv == (SV*)gv ? "*" : "");
+    gv_fullname3(sv, gv, sv == (const SV*)gv ? "*" : "");
 }
 
-/* XXX compatibility with versions <= 5.003. */
+/* compatibility with versions <= 5.003. */
 void
-Perl_gv_efullname(pTHX_ SV *sv, GV *gv)
+Perl_gv_efullname(pTHX_ SV *sv, const GV *gv)
 {
-    gv_efullname3(sv, gv, sv == (SV*)gv ? "*" : "");
+    gv_efullname3(sv, gv, sv == (const SV*)gv ? "*" : "");
 }
 
 IO *
 Perl_newIO(pTHX)
 {
-    IO *io;
     GV *iogv;
+    IO * const io = (IO*)NEWSV(0,0);
 
-    io = (IO*)NEWSV(0,0);
     sv_upgrade((SV *)io,SVt_PVIO);
     SvREFCNT(io) = 1;
     SvOBJECT_on(io);
-    /* Clear the stashcache because a new IO could overrule a 
-       package name */
+    /* Clear the stashcache because a new IO could overrule a package name */
     hv_clear(PL_stashcache);
     iogv = gv_fetchpv("FileHandle::", FALSE, SVt_PVHV);
     /* unless exists($main::{FileHandle}) and defined(%main::FileHandle::) */
     if (!(iogv && GvHV(iogv) && HvARRAY(GvHV(iogv))))
       iogv = gv_fetchpv("IO::Handle::", TRUE, SVt_PVHV);
-    SvSTASH(io) = (HV*)SvREFCNT_inc(GvHV(iogv));
+    SvSTASH_set(io, (HV*)SvREFCNT_inc(GvHV(iogv)));
     return io;
 }
 
 void
 Perl_gv_check(pTHX_ HV *stash)
 {
-    register HE *entry;
     register I32 i;
-    register GV *gv;
-    HV *hv;
 
     if (!HvARRAY(stash))
 	return;
     for (i = 0; i <= (I32) HvMAX(stash); i++) {
+        const HE *entry;
 	for (entry = HvARRAY(stash)[i]; entry; entry = HeNEXT(entry)) {
+            register GV *gv;
+            HV *hv;
 	    if (HeKEY(entry)[HeKLEN(entry)-1] == ':' &&
 		(gv = (GV*)HeVAL(entry)) && isGV(gv) && (hv = GvHV(gv)))
 	    {
@@ -1190,7 +1253,7 @@ Perl_gv_check(pTHX_ HV *stash)
 		     gv_check(hv);              /* nested package */
 	    }
 	    else if (isALPHA(*HeKEY(entry))) {
-		char *file;
+                const char *file;
 		gv = (GV*)HeVAL(entry);
 		if (SvTYPE(gv) != SVt_PVGV || GvMULTI(gv))
 		    continue;
@@ -1210,20 +1273,20 @@ Perl_gv_check(pTHX_ HV *stash)
 		}
 		CopLINE_set(PL_curcop, GvLINE(gv));
 #ifdef USE_ITHREADS
-		CopFILE(PL_curcop) = file;	/* set for warning */
+		CopFILE(PL_curcop) = (char *)file;	/* set for warning */
 #else
 		CopFILEGV(PL_curcop) = gv_fetchfile(file);
 #endif
 		Perl_warner(aTHX_ packWARN(WARN_ONCE),
 			"Name \"%s::%s\" used only once: possible typo",
-			HvNAME(stash), GvNAME(gv));
+			HvNAME_get(stash), GvNAME(gv));
 	    }
 	}
     }
 }
 
 GV *
-Perl_newGVgen(pTHX_ char *pack)
+Perl_newGVgen(pTHX_ const char *pack)
 {
     return gv_fetchpv(Perl_form(aTHX_ "%s::_GEN_%ld", pack, (long)PL_gensym++),
 		      TRUE, SVt_PVGV);
@@ -1278,12 +1341,14 @@ Perl_gp_free(pTHX_ GV *gv)
 
     if (gp->gp_sv) SvREFCNT_dec(gp->gp_sv);
     if (gp->gp_av) SvREFCNT_dec(gp->gp_av);
-    if (gp->gp_hv) {
-	 if (PL_stashcache && HvNAME(gp->gp_hv))
-	      hv_delete(PL_stashcache,
-			HvNAME(gp->gp_hv), strlen(HvNAME(gp->gp_hv)),
-			G_DISCARD);
-	 SvREFCNT_dec(gp->gp_hv);
+    /* FIXME - another reference loop GV -> symtab -> GV ?
+       Somehow gp->gp_hv can end up pointing at freed garbage.  */
+    if (gp->gp_hv && SvTYPE(gp->gp_hv) == SVt_PVHV) {
+	const char *hvname = HvNAME_get(gp->gp_hv);
+	if (PL_stashcache && hvname)
+	    hv_delete(PL_stashcache, hvname, HvNAMELEN_get(gp->gp_hv),
+		      G_DISCARD);
+	SvREFCNT_dec(gp->gp_hv);
     }
     if (gp->gp_io)   SvREFCNT_dec(gp->gp_io);
     if (gp->gp_cv)   SvREFCNT_dec(gp->gp_cv);
@@ -1296,11 +1361,13 @@ Perl_gp_free(pTHX_ GV *gv)
 int
 Perl_magic_freeovrld(pTHX_ SV *sv, MAGIC *mg)
 {
-    AMT *amtp = (AMT*)mg->mg_ptr;
+    AMT * const amtp = (AMT*)mg->mg_ptr;
+    PERL_UNUSED_ARG(sv);
+
     if (amtp && AMT_AMAGIC(amtp)) {
 	int i;
 	for (i = 1; i < NofAMmeth; i++) {
-	    CV *cv = amtp->table[i];
+	    CV * const cv = amtp->table[i];
 	    if (cv != Nullcv) {
 		SvREFCNT_dec((SV *) cv);
 		amtp->table[i] = Nullcv;
@@ -1315,10 +1382,8 @@ Perl_magic_freeovrld(pTHX_ SV *sv, MAGIC *mg)
 bool
 Perl_Gv_AMupdate(pTHX_ HV *stash)
 {
-  GV* gv;
-  CV* cv;
-  MAGIC* mg=mg_find((SV*)stash, PERL_MAGIC_overload_table);
-  AMT *amtp = (mg) ? (AMT*)mg->mg_ptr: (AMT *) NULL;
+  MAGIC* const mg = mg_find((SV*)stash, PERL_MAGIC_overload_table);
+  AMT * const amtp = (mg) ? (AMT*)mg->mg_ptr: (AMT *) NULL;
   AMT amt;
 
   if (mg && amtp->was_ok_am == PL_amagic_generation
@@ -1326,7 +1391,7 @@ Perl_Gv_AMupdate(pTHX_ HV *stash)
       return (bool)AMT_OVERLOADED(amtp);
   sv_unmagic((SV*)stash, PERL_MAGIC_overload_table);
 
-  DEBUG_o( Perl_deb(aTHX_ "Recalcing overload magic in package %s\n",HvNAME(stash)) );
+  DEBUG_o( Perl_deb(aTHX_ "Recalcing overload magic in package %s\n",HvNAME_get(stash)) );
 
   Zero(&amt,1,AMT);
   amt.was_ok_am = PL_amagic_generation;
@@ -1337,17 +1402,21 @@ Perl_Gv_AMupdate(pTHX_ HV *stash)
   {
     int filled = 0, have_ovl = 0;
     int i, lim = 1;
-    SV* sv = NULL;
 
     /* Work with "fallback" key, which we assume to be first in PL_AMG_names */
 
     /* Try to find via inheritance. */
-    gv = gv_fetchmeth(stash, PL_AMG_names[0], 2, -1);
-    if (gv)
-	sv = GvSV(gv);
+    GV *gv = gv_fetchmeth(stash, PL_AMG_names[0], 2, -1);
+    SV * const sv = gv ? GvSV(gv) : NULL;
+    CV* cv;
 
     if (!gv)
 	lim = DESTROY_amg;		/* Skip overloading entries. */
+#ifdef PERL_DONT_CREATE_GVSV
+    else if (!sv) {
+	/* Equivalent to !SvTRUE and !SvOK  */
+    }
+#endif
     else if (SvTRUE(sv))
 	amt.fallback=AMGfallYES;
     else if (SvOK(sv))
@@ -1356,13 +1425,13 @@ Perl_Gv_AMupdate(pTHX_ HV *stash)
     for (i = 1; i < lim; i++)
 	amt.table[i] = Nullcv;
     for (; i < NofAMmeth; i++) {
-	char *cooky = (char*)PL_AMG_names[i];
+	const char *cooky = PL_AMG_names[i];
 	/* Human-readable form, for debugging: */
-	char *cp = (i >= DESTROY_amg ? cooky : AMG_id2name(i));
-	STRLEN l = strlen(cooky);
+	const char *cp = (i >= DESTROY_amg ? cooky : AMG_id2name(i));
+	const STRLEN l = strlen(cooky);
 
-	DEBUG_o( Perl_deb(aTHX_ "Checking overloading of `%s' in package `%.256s'\n",
-		     cp, HvNAME(stash)) );
+	DEBUG_o( Perl_deb(aTHX_ "Checking overloading of \"%s\" in package \"%.256s\"\n",
+		     cp, HvNAME_get(stash)) );
 	/* don't fill the cache while looking up!
 	   Creation of inheritance stubs in intermediate packages may
 	   conflict with the logic of runtime method substitution.
@@ -1376,33 +1445,34 @@ Perl_Gv_AMupdate(pTHX_ HV *stash)
 	    gv = Perl_gv_fetchmeth(aTHX_ stash, cooky, l, -1);
         cv = 0;
         if (gv && (cv = GvCV(gv))) {
+	    const char *hvname;
 	    if (GvNAMELEN(CvGV(cv)) == 3 && strEQ(GvNAME(CvGV(cv)), "nil")
-		&& strEQ(HvNAME(GvSTASH(CvGV(cv))), "overload")) {
+		&& strEQ(hvname = HvNAME_get(GvSTASH(CvGV(cv))), "overload")) {
 		/* This is a hack to support autoloading..., while
 		   knowing *which* methods were declared as overloaded. */
 		/* GvSV contains the name of the method. */
 		GV *ngv = Nullgv;
-		
-		DEBUG_o( Perl_deb(aTHX_ "Resolving method `%"SVf256\
-			"' for overloaded `%s' in package `%.256s'\n",
-			     GvSV(gv), cp, HvNAME(stash)) );
-		if (!SvPOK(GvSV(gv))
-		    || !(ngv = gv_fetchmethod_autoload(stash, SvPVX(GvSV(gv)),
+		SV *gvsv = GvSV(gv);
+
+		DEBUG_o( Perl_deb(aTHX_ "Resolving method \"%"SVf256\
+			"\" for overloaded \"%s\" in package \"%.256s\"\n",
+			     GvSV(gv), cp, hvname) );
+		if (!gvsv || !SvPOK(gvsv)
+		    || !(ngv = gv_fetchmethod_autoload(stash, SvPVX_const(gvsv),
 						       FALSE)))
 		{
-		    /* Can be an import stub (created by `can'). */
-		    SV *gvsv = GvSV(gv);
-		    const char *name = SvPOK(gvsv) ?  SvPVX(gvsv) : "???";
-		    Perl_croak(aTHX_ "%s method `%.256s' overloading `%s' "\
-				"in package `%.256s'",
+		    /* Can be an import stub (created by "can"). */
+		    const char * const name = (gvsv && SvPOK(gvsv)) ?  SvPVX_const(gvsv) : "???";
+		    Perl_croak(aTHX_ "%s method \"%.256s\" overloading \"%s\" "\
+				"in package \"%.256s\"",
 			       (GvCVGEN(gv) ? "Stub found while resolving"
 				: "Can't resolve"),
-			       name, cp, HvNAME(stash));
+			       name, cp, hvname);
 		}
 		cv = GvCV(gv = ngv);
 	    }
-	    DEBUG_o( Perl_deb(aTHX_ "Overloading `%s' in package `%.256s' via `%.256s::%.256s' \n",
-			 cp, HvNAME(stash), HvNAME(GvSTASH(CvGV(cv))),
+	    DEBUG_o( Perl_deb(aTHX_ "Overloading \"%s\" in package \"%.256s\" via \"%.256s::%.256s\"\n",
+			 cp, HvNAME_get(stash), HvNAME_get(GvSTASH(CvGV(cv))),
 			 GvNAME(CvGV(cv))) );
 	    filled = 1;
 	    if (i < DESTROY_amg)
@@ -1436,9 +1506,8 @@ Perl_gv_handler(pTHX_ HV *stash, I32 id)
 {
     MAGIC *mg;
     AMT *amtp;
-    CV *ret;
 
-    if (!stash || !HvNAME(stash))
+    if (!stash || !HvNAME_get(stash))
         return Nullcv;
     mg = mg_find((SV*)stash, PERL_MAGIC_overload_table);
     if (!mg) {
@@ -1451,20 +1520,20 @@ Perl_gv_handler(pTHX_ HV *stash, I32 id)
 	 || amtp->was_ok_sub != PL_sub_generation )
 	goto do_update;
     if (AMT_AMAGIC(amtp)) {
-	ret = amtp->table[id];
+	CV * const ret = amtp->table[id];
 	if (ret && isGV(ret)) {		/* Autoloading stab */
 	    /* Passing it through may have resulted in a warning
 	       "Inherited AUTOLOAD for a non-method deprecated", since
 	       our caller is going through a function call, not a method call.
 	       So return the CV for AUTOLOAD, setting $AUTOLOAD. */
-	    GV *gv = gv_fetchmethod(stash, (char*)PL_AMG_names[id]);
+	    GV *gv = gv_fetchmethod(stash, PL_AMG_names[id]);
 
 	    if (gv && GvCV(gv))
 		return GvCV(gv);
 	}
 	return ret;
     }
-    
+
     return Nullcv;
 }
 
@@ -1472,12 +1541,15 @@ Perl_gv_handler(pTHX_ HV *stash, I32 id)
 SV*
 Perl_amagic_call(pTHX_ SV *left, SV *right, int method, int flags)
 {
+  dVAR;
   MAGIC *mg;
   CV *cv=NULL;
   CV **cvp=NULL, **ocvp=NULL;
   AMT *amtp=NULL, *oamtp=NULL;
-  int off=0, off1, lr=0, assign=AMGf_assign & flags, notfound=0;
-  int postpr = 0, force_cpy = 0, assignshift = assign ? 1 : 0;
+  int off = 0, off1, lr = 0, notfound = 0;
+  int postpr = 0, force_cpy = 0;
+  int assign = AMGf_assign & flags;
+  const int assignshift = assign ? 1 : 0;
 #ifdef DEBUGGING
   int fl=0;
 #endif
@@ -1494,7 +1566,7 @@ Perl_amagic_call(pTHX_ SV *left, SV *right, int method, int flags)
 		  (
 #ifdef DEBUGGING
 		   fl = 1,
-#endif 
+#endif
 		   cv = cvp[off=method])))) {
     lr = -1;			/* Call method for left argument */
   } else {
@@ -1527,12 +1599,12 @@ Perl_amagic_call(pTHX_ SV *left, SV *right, int method, int flags)
 	 case string_amg:
 	   (void)((cv = cvp[off=numer_amg]) || (cv = cvp[off=bool__amg]));
 	   break;
- case not_amg:
-   (void)((cv = cvp[off=bool__amg])
-	  || (cv = cvp[off=numer_amg])
-	  || (cv = cvp[off=string_amg]));
-   postpr = 1;
-   break;
+         case not_amg:
+           (void)((cv = cvp[off=bool__amg])
+                  || (cv = cvp[off=numer_amg])
+                  || (cv = cvp[off=string_amg]));
+           postpr = 1;
+           break;
 	 case copy_amg:
 	   {
 	     /*
@@ -1547,7 +1619,7 @@ Perl_amagic_call(pTHX_ SV *left, SV *right, int method, int flags)
 		 */
 		SV* newref = newSVsv(tmpRef);
 		SvOBJECT_on(newref);
-		SvSTASH(newref) = (HV*)SvREFCNT_inc(SvSTASH(tmpRef));
+		SvSTASH_set(newref, (HV*)SvREFCNT_inc(SvSTASH(tmpRef)));
 		return newref;
 	     }
 	   }
@@ -1661,14 +1733,14 @@ Perl_amagic_call(pTHX_ SV *left, SV *right, int method, int flags)
 	SV *msg;
 	if (off==-1) off=method;
 	msg = sv_2mortal(Perl_newSVpvf(aTHX_
-		      "Operation `%s': no method found,%sargument %s%s%s%s",
+		      "Operation \"%s\": no method found,%sargument %s%s%s%s",
 		      AMG_id2name(method + assignshift),
 		      (flags & AMGf_unary ? " " : "\n\tleft "),
 		      SvAMAGIC(left)?
 		        "in overloaded package ":
 		        "has no overloaded magic",
 		      SvAMAGIC(left)?
-		        HvNAME(SvSTASH(SvRV(left))):
+		        HvNAME_get(SvSTASH(SvRV(left))):
 		        "",
 		      SvAMAGIC(right)?
 		        ",\n\tright argument in overloaded package ":
@@ -1676,10 +1748,10 @@ Perl_amagic_call(pTHX_ SV *left, SV *right, int method, int flags)
 			 ? ""
 			 : ",\n\tright argument has no overloaded magic"),
 		      SvAMAGIC(right)?
-		        HvNAME(SvSTASH(SvRV(right))):
+		        HvNAME_get(SvSTASH(SvRV(right))):
 		        ""));
 	if (amtp && amtp->fallback >= AMGfallYES) {
-	  DEBUG_o( Perl_deb(aTHX_ "%s", SvPVX(msg)) );
+	  DEBUG_o( Perl_deb(aTHX_ "%s", SvPVX_const(msg)) );
 	} else {
 	  Perl_croak(aTHX_ "%"SVf, msg);
 	}
@@ -1691,17 +1763,17 @@ Perl_amagic_call(pTHX_ SV *left, SV *right, int method, int flags)
 #ifdef DEBUGGING
   if (!notfound) {
     DEBUG_o(Perl_deb(aTHX_
-		     "Overloaded operator `%s'%s%s%s:\n\tmethod%s found%s in package %s%s\n",
+		     "Overloaded operator \"%s\"%s%s%s:\n\tmethod%s found%s in package %s%s\n",
 		     AMG_id2name(off),
 		     method+assignshift==off? "" :
-		     " (initially `",
+		     " (initially \"",
 		     method+assignshift==off? "" :
 		     AMG_id2name(method+assignshift),
-		     method+assignshift==off? "" : "')",
+		     method+assignshift==off? "" : "\")",
 		     flags & AMGf_unary? "" :
 		     lr==1 ? " for right argument": " for left argument",
 		     flags & AMGf_unary? " for argument" : "",
-		     stash ? HvNAME(stash) : "null",
+		     stash ? HvNAME_get(stash) : "null",
 		     fl? ",\n\tassignment variant used": "") );
   }
 #endif
@@ -1735,7 +1807,7 @@ Perl_amagic_call(pTHX_ SV *left, SV *right, int method, int flags)
     dSP;
     BINOP myop;
     SV* res;
-    bool oldcatch = CATCH_GET;
+    const bool oldcatch = CATCH_GET;
 
     CATCH_SET(TRUE);
     Zero(&myop, 1, BINOP);
@@ -1773,7 +1845,7 @@ Perl_amagic_call(pTHX_ SV *left, SV *right, int method, int flags)
     CATCH_SET(oldcatch);
 
     if (postpr) {
-      int ans=0;
+      int ans;
       switch (method) {
       case le_amg:
       case sle_amg:
@@ -1798,6 +1870,8 @@ Perl_amagic_call(pTHX_ SV *left, SV *right, int method, int flags)
 	SvSetSV(left,res); return left;
       case not_amg:
 	ans=!SvTRUE(res); break;
+      default:
+        ans=0; break;
       }
       return boolSV(ans);
     } else if (method==copy_amg) {
@@ -1812,6 +1886,22 @@ Perl_amagic_call(pTHX_ SV *left, SV *right, int method, int flags)
 }
 
 /*
+=for apidoc is_gv_magical_sv
+
+Returns C<TRUE> if given the name of a magical GV. Calls is_gv_magical.
+
+=cut
+*/
+
+bool
+Perl_is_gv_magical_sv(pTHX_ SV *name, U32 flags)
+{
+    STRLEN len;
+    const char *temp = SvPV_const(name, len);
+    return is_gv_magical(temp, len, flags);
+}
+
+/*
 =for apidoc is_gv_magical
 
 Returns C<TRUE> if given the name of a magical GV.
@@ -1822,110 +1912,139 @@ created even in rvalue contexts.
 C<flags> is not used at present but available for future extension to
 allow selecting particular classes of magical variable.
 
+Currently assumes that C<name> is NUL terminated (as well as len being valid).
+This assumption is met by all callers within the perl core, which all pass
+pointers returned by SvPV.
+
 =cut
 */
 bool
-Perl_is_gv_magical(pTHX_ char *name, STRLEN len, U32 flags)
+Perl_is_gv_magical(pTHX_ const char *name, STRLEN len, U32 flags)
 {
-    if (!len)
-	return FALSE;
+    PERL_UNUSED_ARG(flags);
 
-    switch (*name) {
-    case 'I':
-	if (len == 3 && strEQ(name, "ISA"))
-	    goto yes;
-	break;
-    case 'O':
-	if (len == 8 && strEQ(name, "OVERLOAD"))
-	    goto yes;
-	break;
-    case 'S':
-	if (len == 3 && strEQ(name, "SIG"))
-	    goto yes;
-	break;
-    case '\017':   /* $^O & $^OPEN */
-	if (len == 1
-	    || (len == 4 && strEQ(name, "\017PEN")))
-	{
-	    goto yes;
-	}
-	break;
-    case '\025':
-        if (len > 1 && strEQ(name, "\025NICODE"))
-	    goto yes;
-    case '\027':   /* $^W & $^WARNING_BITS */
-	if (len == 1
-	    || (len == 12 && strEQ(name, "\027ARNING_BITS"))
-	    )
+    if (len > 1) {
+	const char * const name1 = name + 1;
+	switch (*name) {
+	case 'I':
+	    if (len == 3 && name1[1] == 'S' && name[2] == 'A')
+		goto yes;
+	    break;
+	case 'O':
+	    if (len == 8 && strEQ(name1, "VERLOAD"))
+		goto yes;
+	    break;
+	case 'S':
+	    if (len == 3 && name[1] == 'I' && name[2] == 'G')
+		goto yes;
+	    break;
+	    /* Using ${^...} variables is likely to be sufficiently rare that
+	       it seems sensible to avoid the space hit of also checking the
+	       length.  */
+	case '\017':   /* ${^OPEN} */
+	    if (strEQ(name1, "PEN"))
+		goto yes;
+	    break;
+	case '\024':   /* ${^TAINT} */
+	    if (strEQ(name1, "AINT"))
+		goto yes;
+	    break;
+	case '\025':	/* ${^UNICODE} */
+	    if (strEQ(name1, "NICODE"))
+		goto yes;
+	    if (strEQ(name1, "TF8LOCALE"))
+		goto yes;
+	    break;
+	case '\027':   /* ${^WARNING_BITS} */
+	    if (strEQ(name1, "ARNING_BITS"))
+		goto yes;
+	    break;
+	case '1':
+	case '2':
+	case '3':
+	case '4':
+	case '5':
+	case '6':
+	case '7':
+	case '8':
+	case '9':
 	{
-	    goto yes;
-	}
-	break;
-
-    case '&':
-    case '`':
-    case '\'':
-    case ':':
-    case '?':
-    case '!':
-    case '-':
-    case '#':
-    case '[':
-    case '^':
-    case '~':
-    case '=':
-    case '%':
-    case '.':
-    case '(':
-    case ')':
-    case '<':
-    case '>':
-    case ',':
-    case '\\':
-    case '/':
-    case '|':
-    case '+':
-    case ';':
-    case ']':
-    case '\001':   /* $^A */
-    case '\003':   /* $^C */
-    case '\004':   /* $^D */
-    case '\005':   /* $^E */
-    case '\006':   /* $^F */
-    case '\010':   /* $^H */
-    case '\011':   /* $^I, NOT \t in EBCDIC */
-    case '\014':   /* $^L */
-    case '\016':   /* $^N */
-    case '\020':   /* $^P */
-    case '\023':   /* $^S */
-    case '\026':   /* $^V */
-	if (len == 1)
-	    goto yes;
-	break;
-    case '\024':   /* $^T, ${^TAINT} */
-        if (len == 1 || strEQ(name, "\024AINT"))
-            goto yes;
-        break;
-    case '1':
-    case '2':
-    case '3':
-    case '4':
-    case '5':
-    case '6':
-    case '7':
-    case '8':
-    case '9':
-	if (len > 1) {
-	    char *end = name + len;
+	    const char *end = name + len;
 	    while (--end > name) {
 		if (!isDIGIT(*end))
 		    return FALSE;
 	    }
+	    goto yes;
+	}
+	}
+    } else {
+	/* Because we're already assuming that name is NUL terminated
+	   below, we can treat an empty name as "\0"  */
+	switch (*name) {
+	case '&':
+	case '`':
+	case '\'':
+	case ':':
+	case '?':
+	case '!':
+	case '-':
+	case '#':
+	case '[':
+	case '^':
+	case '~':
+	case '=':
+	case '%':
+	case '.':
+	case '(':
+	case ')':
+	case '<':
+	case '>':
+	case ',':
+	case '\\':
+	case '/':
+	case '|':
+	case '+':
+	case ';':
+	case ']':
+	case '\001':   /* $^A */
+	case '\003':   /* $^C */
+	case '\004':   /* $^D */
+	case '\005':   /* $^E */
+	case '\006':   /* $^F */
+	case '\010':   /* $^H */
+	case '\011':   /* $^I, NOT \t in EBCDIC */
+	case '\014':   /* $^L */
+	case '\016':   /* $^N */
+	case '\017':   /* $^O */
+	case '\020':   /* $^P */
+	case '\023':   /* $^S */
+	case '\024':   /* $^T */
+	case '\026':   /* $^V */
+	case '\027':   /* $^W */
+	case '1':
+	case '2':
+	case '3':
+	case '4':
+	case '5':
+	case '6':
+	case '7':
+	case '8':
+	case '9':
+	yes:
+	    return TRUE;
+	default:
+	    break;
 	}
-    yes:
-	return TRUE;
-    default:
-	break;
     }
     return FALSE;
 }
+
+/*
+ * Local variables:
+ * c-indentation-style: bsd
+ * c-basic-offset: 4
+ * indent-tabs-mode: t
+ * End:
+ *
+ * ex: set ts=8 sts=4 sw=4 noet:
+ */