X-Git-Url: https://perl5.git.perl.org/perl5.git/blobdiff_plain/e62f0680cdecd36f79df8a7dabc61c6a2739f07a..1c321dc6ba82145ce5173a7eb3ec132cf550fc22:/gv.c

diff --git a/gv.c b/gv.c
index 68dbd72..e4c59b5 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, 2005, by Larry Wall and others
+ *    2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 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.
@@ -37,6 +37,19 @@ Perl stores its global variables.
 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(0);
+    return gv;
+}
+#endif
+
 GV *
 Perl_gv_AVadd(pTHX_ register GV *gv)
 {
@@ -60,8 +73,23 @@ Perl_gv_HVadd(pTHX_ register GV *gv)
 GV *
 Perl_gv_IOadd(pTHX_ register GV *gv)
 {
-    if (!gv || SvTYPE((SV*)gv) != SVt_PVGV)
-	Perl_croak(aTHX_ "Bad symbol for filehandle");
+    dVAR;
+    if (!gv || SvTYPE((SV*)gv) != SVt_PVGV) {
+
+        /*
+         * if it walks like a dirhandle, then let's assume that
+         * this is a dirhandle.
+         */
+	const char * const fh =
+			 PL_op->op_type ==  OP_READDIR ||
+                         PL_op->op_type ==  OP_TELLDIR ||
+                         PL_op->op_type ==  OP_SEEKDIR ||
+                         PL_op->op_type ==  OP_REWINDDIR ||
+                         PL_op->op_type ==  OP_CLOSEDIR ?
+                         "dirhandle" : "filehandle";
+        Perl_croak(aTHX_ "Bad symbol for %s", fh);
+    }
+
     if (!GvIOp(gv)) {
 #ifdef GV_UNIQUE_CHECK
         if (GvUNIQUE(gv)) {
@@ -76,73 +104,153 @@ Perl_gv_IOadd(pTHX_ register GV *gv)
 GV *
 Perl_gv_fetchfile(pTHX_ const char *name)
 {
+    dVAR;
     char smallbuf[256];
     char *tmpbuf;
     STRLEN tmplen;
     GV *gv;
 
     if (!PL_defstash)
-	return Nullgv;
+	return NULL;
 
     tmplen = strlen(name) + 2;
     if (tmplen < sizeof smallbuf)
 	tmpbuf = smallbuf;
     else
-	New(603, tmpbuf, tmplen + 1, char);
+	Newx(tmpbuf, tmplen + 1, char);
     /* 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);
+	    hv_magic(GvHVn(gv_AVadd(gv)), NULL, PERL_MAGIC_dbfile);
     }
     if (tmpbuf != smallbuf)
 	Safefree(tmpbuf);
     return gv;
 }
 
+/*
+=for apidoc gv_const_sv
+
+If C<gv> is a typeglob whose subroutine entry is a constant sub eligible for
+inlining, or C<gv> is a placeholder reference that would be promoted to such
+a typeglob, then returns the value returned by the sub.  Otherwise, returns
+NULL.
+
+=cut
+*/
+
+SV *
+Perl_gv_const_sv(pTHX_ GV *gv)
+{
+    if (SvTYPE(gv) == SVt_PVGV)
+	return cv_const_sv(GvCVu(gv));
+    return SvROK(gv) ? SvRV(gv) : NULL;
+}
+
+GP *
+Perl_newGP(pTHX_ GV *const gv)
+{
+    GP *gp;
+    const char *const file
+	= (PL_curcop && CopFILE(PL_curcop)) ? CopFILE(PL_curcop) : "";
+    STRLEN len = strlen(file);
+    U32 hash;
+
+    PERL_HASH(hash, file, len);
+
+    Newxz(gp, 1, GP);
+
+#ifndef PERL_DONT_CREATE_GVSV
+    gp->gv_sv = newSV(0);
+#endif
+
+    gp->gp_line = PL_curcop ? CopLINE(PL_curcop) : 0;
+    /* XXX Ideally this cast would be replaced with a change to const char*
+       in the struct.  */
+    gp->gp_file_hek = share_hek(file, len, hash);
+    gp->gp_egv = gv;
+    gp->gp_refcnt = 1;
+
+    return gp;
+}
+
 void
 Perl_gv_init(pTHX_ GV *gv, HV *stash, const char *name, STRLEN len, int multi)
 {
     dVAR;
-    register GP *gp;
-    const bool doproto = SvTYPE(gv) > SVt_NULL;
+    const U32 old_type = SvTYPE(gv);
+    const bool doproto = old_type > SVt_NULL;
     const char * const proto = (doproto && SvPOK(gv)) ? SvPVX_const(gv) : NULL;
+    SV *const has_constant = doproto && SvROK(gv) ? SvRV(gv) : NULL;
+    const U32 exported_constant = has_constant ? SvPCS_IMPORTED(gv) : 0;
+
+    assert (!(proto && has_constant));
+
+    if (has_constant) {
+	/* The constant has to be a simple scalar type.  */
+	switch (SvTYPE(has_constant)) {
+	case SVt_PVAV:
+	case SVt_PVHV:
+	case SVt_PVCV:
+	case SVt_PVFM:
+	case SVt_PVIO:
+            Perl_croak(aTHX_ "Cannot convert a reference to %s to typeglob",
+		       sv_reftype(has_constant, 0));
+	default: NOOP;
+	}
+	SvRV_set(gv, NULL);
+	SvROK_off(gv);
+    }
 
-    sv_upgrade((SV*)gv, SVt_PVGV);
+
+    if (old_type < SVt_PVGV) {
+	if (old_type >= SVt_PV)
+	    SvCUR_set(gv, 0);
+	sv_upgrade((SV*)gv, SVt_PVGV);
+    }
     if (SvLEN(gv)) {
 	if (proto) {
 	    SvPV_set(gv, NULL);
 	    SvLEN_set(gv, 0);
 	    SvPOK_off(gv);
 	} else
-	    Safefree(SvPVX_const(gv));
+	    Safefree(SvPVX_mutable(gv));
     }
-    Newz(602, gp, 1, GP);
-    GvGP(gv) = gp_ref(gp);
-    GvSV(gv) = NEWSV(72,0);
-    GvLINE(gv) = CopLINE(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);
-    GvNAME(gv) = savepvn(name, len);
-    GvNAMELEN(gv) = len;
+    SvIOK_off(gv);
+    isGV_with_GP_on(gv);
+
+    GvGP(gv) = Perl_newGP(aTHX_ gv);
+    GvSTASH(gv) = stash;
+    if (stash)
+	Perl_sv_add_backref(aTHX_ (SV*)stash, (SV*)gv);
+    gv_name_set(gv, name, len, GV_ADD);
     if (multi || doproto)              /* doproto means it _was_ mentioned */
 	GvMULTI_on(gv);
     if (doproto) {			/* Replicate part of newSUB here. */
-	SvIOK_off(gv);
 	ENTER;
-	/* XXX unsafe for threads if eval_owner isn't held */
-	start_subparse(0,0);		/* Create CV in compcv. */
-	GvCV(gv) = PL_compcv;
+	if (has_constant) {
+	    /* newCONSTSUB takes ownership of the reference from us.  */
+	    GvCV(gv) = newCONSTSUB(stash, name, has_constant);
+	    /* If this reference was a copy of another, then the subroutine
+	       must have been "imported", by a Perl space assignment to a GV
+	       from a reference to CV.  */
+	    if (exported_constant)
+		GvIMPORTED_CV_on(gv);
+	} else {
+	    /* XXX unsafe for threads if eval_owner isn't held */
+	    (void) start_subparse(0,0);	/* Create empty CV in compcv. */
+	    GvCV(gv) = PL_compcv;
+	}
 	LEAVE;
 
 	PL_sub_generation++;
@@ -169,6 +277,15 @@ 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:
+    case SVt_PVGV:
+	break;
+    default:
+	(void)GvSVn(gv);
+#endif
     }
 }
 
@@ -196,17 +313,19 @@ obtained from the GV with the C<GvCV> macro.
 GV *
 Perl_gv_fetchmeth(pTHX_ HV *stash, const char *name, STRLEN len, I32 level)
 {
+    dVAR;
     AV* av;
     GV* topgv;
     GV* gv;
     GV** gvp;
     CV* cv;
     const char *hvname;
+    HV* lastchance = NULL;
 
     /* UNIVERSAL methods should be callable without a stash */
     if (!stash) {
 	level = -1;  /* probably appropriate */
-	if(!(stash = gv_stashpvn("UNIVERSAL", 9, FALSE)))
+	if(!(stash = gv_stashpvs("UNIVERSAL", FALSE)))
 	    return 0;
     }
 
@@ -223,7 +342,7 @@ Perl_gv_fetchmeth(pTHX_ HV *stash, const char *name, STRLEN len, I32 level)
 
     gvp = (GV**)hv_fetch(stash, name, len, (level >= 0));
     if (!gvp)
-	topgv = Nullgv;
+	topgv = NULL;
     else {
 	topgv = *gvp;
 	if (SvTYPE(topgv) != SVt_PVGV)
@@ -234,15 +353,15 @@ Perl_gv_fetchmeth(pTHX_ HV *stash, const char *name, STRLEN len, I32 level)
 		return topgv;
 	    /* Stale cached entry: junk it */
 	    SvREFCNT_dec(cv);
-	    GvCV(topgv) = cv = Nullcv;
+	    GvCV(topgv) = cv = NULL;
 	    GvCVGEN(topgv) = 0;
 	}
 	else if (GvCVGEN(topgv) == PL_sub_generation)
 	    return 0;  /* cache indicates sub doesn't exist */
     }
 
-    gvp = (GV**)hv_fetch(stash, "ISA", 3, FALSE);
-    av = (gvp && (gv = *gvp) && gv != (GV*)&PL_sv_undef) ? GvAV(gv) : Nullav;
+    gvp = (GV**)hv_fetchs(stash, "ISA", FALSE);
+    av = (gvp && (gv = *gvp) && gv != (GV*)&PL_sv_undef) ? GvAV(gv) : NULL;
 
     /* create and re-create @.*::SUPER::ISA on demand */
     if (!av || !SvMAGIC(av)) {
@@ -253,15 +372,15 @@ Perl_gv_fetchmeth(pTHX_ HV *stash, const char *name, STRLEN len, I32 level)
 
 	    packlen -= 7;
 	    basestash = gv_stashpvn(hvname, packlen, TRUE);
-	    gvp = (GV**)hv_fetch(basestash, "ISA", 3, FALSE);
+	    gvp = (GV**)hv_fetchs(basestash, "ISA", FALSE);
 	    if (gvp && (gv = *gvp) != (GV*)&PL_sv_undef && (av = GvAV(gv))) {
-		gvp = (GV**)hv_fetch(stash, "ISA", 3, TRUE);
+		gvp = (GV**)hv_fetchs(stash, "ISA", TRUE);
 		if (!gvp || !(gv = *gvp))
 		    Perl_croak(aTHX_ "Cannot create %s::ISA", hvname);
 		if (SvTYPE(gv) != SVt_PVGV)
 		    gv_init(gv, stash, "ISA", 3, TRUE);
 		SvREFCNT_dec(GvAV(gv));
-		GvAV(gv) = (AV*)SvREFCNT_inc(av);
+		GvAV(gv) = (AV*)SvREFCNT_inc_simple(av);
 	    }
 	}
     }
@@ -271,12 +390,12 @@ Perl_gv_fetchmeth(pTHX_ HV *stash, const char *name, STRLEN len, I32 level)
 	/* NOTE: No support for tied ISA */
 	I32 items = AvFILLp(av) + 1;
 	while (items--) {
-	    SV* sv = *svp++;
-	    HV* basestash = gv_stashsv(sv, FALSE);
+	    SV* const sv = *svp++;
+	    HV* const basestash = gv_stashsv(sv, FALSE);
 	    if (!basestash) {
 		if (ckWARN(WARN_MISC))
 		    Perl_warner(aTHX_ packWARN(WARN_MISC), "Can't locate package %"SVf" for @%s::ISA",
-			sv, hvname);
+			SVfARG(sv), hvname);
 		continue;
 	    }
 	    gv = gv_fetchmeth(basestash, name, len,
@@ -289,9 +408,9 @@ Perl_gv_fetchmeth(pTHX_ HV *stash, const char *name, STRLEN len, I32 level)
     /* if at top level, try UNIVERSAL */
 
     if (level == 0 || level == -1) {
-	HV* lastchance;
+	lastchance = gv_stashpvs("UNIVERSAL", FALSE);
 
-	if ((lastchance = gv_stashpvn("UNIVERSAL", 9, FALSE))) {
+	if (lastchance) {
 	    if ((gv = gv_fetchmeth(lastchance, name, len,
 				  (level >= 0) ? level + 1 : level - 1)))
 	    {
@@ -346,40 +465,26 @@ Perl_gv_fetchmeth_autoload(pTHX_ HV *stash, const char *name, STRLEN len, I32 le
 	GV **gvp;
 
 	if (!stash)
-	    return Nullgv;	/* UNIVERSAL::AUTOLOAD could cause trouble */
+	    return NULL;	/* UNIVERSAL::AUTOLOAD could cause trouble */
 	if (len == S_autolen && strnEQ(name, S_autoload, S_autolen))
-	    return Nullgv;
+	    return NULL;
 	if (!(gv = gv_fetchmeth(stash, S_autoload, S_autolen, FALSE)))
-	    return Nullgv;
+	    return NULL;
 	cv = GvCV(gv);
 	if (!(CvROOT(cv) || CvXSUB(cv)))
-	    return Nullgv;
+	    return NULL;
 	/* Have an autoload */
 	if (level < 0)	/* Cannot do without a stub */
 	    gv_fetchmeth(stash, name, len, 0);
 	gvp = (GV**)hv_fetch(stash, name, len, (level >= 0));
 	if (!gvp)
-	    return Nullgv;
+	    return NULL;
 	return *gvp;
     }
     return gv;
 }
 
 /*
-=for apidoc gv_fetchmethod
-
-See L<gv_fetchmethod_autoload>.
-
-=cut
-*/
-
-GV *
-Perl_gv_fetchmethod(pTHX_ HV *stash, const char *name)
-{
-    return gv_fetchmethod_autoload(stash, name, TRUE);
-}
-
-/*
 =for apidoc gv_fetchmethod_autoload
 
 Returns the glob which contains the subroutine to call to invoke the method
@@ -410,13 +515,14 @@ C<call_sv> apply equally to these functions.
 GV *
 Perl_gv_fetchmethod_autoload(pTHX_ HV *stash, const char *name, I32 autoload)
 {
+    dVAR;
     register const char *nend;
-    const char *nsplit = 0;
+    const char *nsplit = NULL;
     GV* gv;
     HV* ostash = stash;
 
     if (stash && SvTYPE(stash) < SVt_PVHV)
-	stash = Nullhv;
+	stash = NULL;
 
     for (nend = name; *nend; nend++) {
 	if (*nend == '\'')
@@ -425,13 +531,13 @@ 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;
 	if ((nsplit - origname) == 5 && strnEQ(origname, "SUPER", 5)) {
 	    /* ->SUPER::method should really be looked up in original stash */
-	    SV *tmpstr = sv_2mortal(Perl_newSVpvf(aTHX_ "%s::SUPER",
+	    SV * const tmpstr = sv_2mortal(Perl_newSVpvf(aTHX_ "%s::SUPER",
 						  CopSTASHPV(PL_curcop)));
 	    /* __PACKAGE__::SUPER stash should be autovivified */
 	    stash = gv_stashpvn(SvPVX_const(tmpstr), SvCUR(tmpstr), TRUE);
@@ -460,7 +566,7 @@ 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;
@@ -492,14 +598,14 @@ Perl_gv_autoload4(pTHX_ HV *stash, const char *name, STRLEN len, I32 method)
     GV* vargv;
     SV* varsv;
     const char *packname = "";
-    STRLEN packname_len;
+    STRLEN packname_len = 0;
 
     if (len == S_autolen && strnEQ(name, S_autoload, S_autolen))
-	return Nullgv;
+	return NULL;
     if (stash) {
 	if (SvTYPE(stash) < SVt_PVHV) {
 	    packname = SvPV_const((SV*)stash, packname_len);
-	    stash = Nullhv;
+	    stash = NULL;
 	}
 	else {
 	    packname = HvNAME_get(stash);
@@ -507,22 +613,23 @@ Perl_gv_autoload4(pTHX_ HV *stash, const char *name, STRLEN len, I32 method)
 	}
     }
     if (!(gv = gv_fetchmeth(stash, S_autoload, S_autolen, FALSE)))
-	return Nullgv;
+	return NULL;
     cv = GvCV(gv);
 
     if (!(CvROOT(cv) || CvXSUB(cv)))
-	return Nullgv;
+	return NULL;
 
     /*
      * Inheriting AUTOLOAD for non-methods works ... for now.
      */
-    if (ckWARN2(WARN_DEPRECATED, WARN_SYNTAX) && !method &&
-	(GvCVGEN(gv) || GvSTASH(gv) != stash))
+    if (!method && (GvCVGEN(gv) || GvSTASH(gv) != stash)
+	&& ckWARN2(WARN_DEPRECATED, WARN_SYNTAX)
+    )
 	Perl_warner(aTHX_ packWARN2(WARN_DEPRECATED, WARN_SYNTAX),
 	  "Use of inherited AUTOLOAD for non-method %s::%.*s() is deprecated",
 	     packname, (int)len, name);
 
-    if (CvXSUB(cv)) {
+    if (CvISXSUB(cv)) {
         /* rather than lookup/init $AUTOLOAD here
          * only to have the XSUB do another lookup for $AUTOLOAD
          * and split that value on the last '::',
@@ -544,39 +651,58 @@ Perl_gv_autoload4(pTHX_ HV *stash, const char *name, STRLEN len, I32 method)
     vargv = *(GV**)hv_fetch(varstash, S_autoload, S_autolen, TRUE);
     ENTER;
 
-    if (!isGV(vargv))
+    if (!isGV(vargv)) {
 	gv_init(vargv, varstash, S_autoload, S_autolen, FALSE);
+#ifdef PERL_DONT_CREATE_GVSV
+	GvSV(vargv) = newSV(0);
+#endif
+    }
     LEAVE;
-    varsv = GvSV(vargv);
+    varsv = GvSVn(vargv);
     sv_setpvn(varsv, packname, packname_len);
-    sv_catpvn(varsv, "::", 2);
+    sv_catpvs(varsv, "::");
     sv_catpvn(varsv, name, len);
-    SvTAINTED_off(varsv);
     return gv;
 }
 
-/* The "gv" parameter should be the glob known to Perl code as *!
- * The scalar must already have been magicalized.
+
+/* require_tie_mod() internal routine for requiring a module
+ * that implements the logic of automatical ties like %! and %-
+ *
+ * The "gv" parameter should be the glob.
+ * "varpv" holds the name of the var, used for error messages
+ * "namesv" holds the module name
+ * "methpv" holds the method name to test for to check that things
+ *   are working reasonably close to as expected
+ * "flags" if flag & 1 then save the scalar before loading.
+ * For the protection of $! to work (it is set by this routine)
+ * the sv slot must already be magicalized.
  */
-STATIC void
-S_require_errno(pTHX_ GV *gv)
+STATIC HV*
+S_require_tie_mod(pTHX_ GV *gv, const char *varpv, SV* namesv, const char *methpv,const U32 flags)
 {
     dVAR;
-    HV* stash = gv_stashpvn("Errno",5,FALSE);
-
-    if (!stash || !(gv_fetchmethod(stash, "TIEHASH"))) {
+    HV* stash = gv_stashsv(namesv, FALSE);
+    
+    if (!stash || !(gv_fetchmethod(stash, methpv))) {
+        SV *module = newSVsv(namesv);
 	dSP;
 	PUTBACK;
 	ENTER;
-	save_scalar(gv); /* keep the value of $! */
-        Perl_load_module(aTHX_ PERL_LOADMOD_NOIMPORT,
-                         newSVpvn("Errno",5), Nullsv);
+	if ( flags & 1 )
+	    save_scalar(gv); 
+        Perl_load_module(aTHX_ PERL_LOADMOD_NOIMPORT, module, NULL);
 	LEAVE;
 	SPAGAIN;
-	stash = gv_stashpvn("Errno",5,FALSE);
-	if (!stash || !(gv_fetchmethod(stash, "TIEHASH")))
-	    Perl_croak(aTHX_ "Can't use %%! because Errno.pm is not available");
+	stash = gv_stashsv(namesv, FALSE);
+	if (!stash)
+	    Perl_croak( aTHX_ "panic: Can't use %%%s because %"SVf" is not available", 
+	        varpv, module);
+	else if (!gv_fetchmethod(stash, methpv))    
+	    Perl_croak( aTHX_ "panic: Can't use %%%s because %"SVf" does not support method %s", 
+	        varpv, module, methpv);
     }
+    return stash;
 }
 
 /*
@@ -611,7 +737,7 @@ package does not exist then NULL is returned.
 HV*
 Perl_gv_stashpvn(pTHX_ const char *name, U32 namelen, I32 create)
 {
-    char smallbuf[256];
+    char smallbuf[128];
     char *tmpbuf;
     HV *stash;
     GV *tmpgv;
@@ -619,12 +745,12 @@ Perl_gv_stashpvn(pTHX_ const char *name, U32 namelen, I32 create)
     if (namelen + 3 < sizeof smallbuf)
 	tmpbuf = smallbuf;
     else
-	New(606, tmpbuf, namelen + 3, char);
+	Newx(tmpbuf, namelen + 3, char);
     Copy(name,tmpbuf,namelen,char);
     tmpbuf[namelen++] = ':';
     tmpbuf[namelen++] = ':';
     tmpbuf[namelen] = '\0';
-    tmpgv = gv_fetchpv(tmpbuf, create, SVt_PVHV);
+    tmpgv = gv_fetchpvn_flags(tmpbuf, namelen, create, SVt_PVHV);
     if (tmpbuf != smallbuf)
 	Safefree(tmpbuf);
     if (!tmpgv)
@@ -633,7 +759,7 @@ Perl_gv_stashpvn(pTHX_ const char *name, U32 namelen, I32 create)
 	GvHV(tmpgv) = newHV();
     stash = GvHV(tmpgv);
     if (!HvNAME_get(stash))
-	Perl_hv_name_set(aTHX_ stash, name, namelen, 0);
+	hv_name_set(stash, name, namelen, 0);
     return stash;
 }
 
@@ -650,7 +776,7 @@ HV*
 Perl_gv_stashsv(pTHX_ SV *sv, I32 create)
 {
     STRLEN len;
-    const char *ptr = SvPV_const(sv,len);
+    const char * const ptr = SvPV_const(sv,len);
     return gv_stashpvn(ptr, len, create);
 }
 
@@ -663,7 +789,7 @@ Perl_gv_fetchpv(pTHX_ const char *nambeg, I32 add, I32 sv_type) {
 GV *
 Perl_gv_fetchsv(pTHX_ SV *name, I32 flags, I32 sv_type) {
     STRLEN len;
-    const char *nambeg = SvPV_const(name, len);
+    const char * const nambeg = SvPV_const(name, len);
     return gv_fetchpvn_flags(nambeg, len, flags | SvUTF8(name), sv_type);
 }
 
@@ -671,42 +797,56 @@ GV *
 Perl_gv_fetchpvn_flags(pTHX_ const char *nambeg, STRLEN full_len, I32 flags,
 		       I32 sv_type)
 {
+    dVAR;
     register const char *name = nambeg;
-    register GV *gv = 0;
+    register GV *gv = NULL;
     GV**gvp;
     I32 len;
-    register const char *namend;
-    HV *stash = 0;
-    const I32 add = flags & ~SVf_UTF8;
-    (void)full_len;
+    register const char *name_cursor;
+    HV *stash = NULL;
+    const I32 no_init = flags & (GV_NOADD_NOINIT | GV_NOINIT);
+    const I32 no_expand = flags & GV_NOEXPAND;
+    const I32 add =
+	flags & ~SVf_UTF8 & ~GV_NOADD_NOINIT & ~GV_NOEXPAND & ~GV_NOTQUAL;
+    const char *const name_end = nambeg + full_len;
+    const char *const name_em1 = name_end - 1;
+
+    if (flags & GV_NOTQUAL) {
+	/* Caller promised that there is no stash, so we can skip the check. */
+	len = full_len;
+	goto no_stash;
+    }
 
-    if (*name == '*' && isALPHA(name[1])) /* accidental stringify on a GV? */
+    if (full_len > 2 && *name == '*' && isALPHA(name[1])) {
+	/* accidental stringify on a GV? */
 	name++;
+    }
 
-    for (namend = name; *namend; namend++) {
-	if ((*namend == ':' && namend[1] == ':')
-	    || (*namend == '\'' && namend[1]))
+    for (name_cursor = name; name_cursor < name_end; name_cursor++) {
+	if ((*name_cursor == ':' && name_cursor < name_em1
+	     && name_cursor[1] == ':')
+	    || (*name_cursor == '\'' && name_cursor[1]))
 	{
 	    if (!stash)
 		stash = PL_defstash;
 	    if (!stash || !SvREFCNT(stash)) /* symbol table under destruction */
-		return Nullgv;
+		return NULL;
 
-	    len = namend - name;
+	    len = name_cursor - name;
 	    if (len > 0) {
-		char smallbuf[256];
+		char smallbuf[128];
 		char *tmpbuf;
 
-		if (len + 3 < sizeof (smallbuf))
+		if (len + 3 < (I32)sizeof (smallbuf))
 		    tmpbuf = smallbuf;
 		else
-		    New(601, tmpbuf, len+3, char);
+		    Newx(tmpbuf, len+3, char);
 		Copy(name, tmpbuf, len, char);
 		tmpbuf[len++] = ':';
 		tmpbuf[len++] = ':';
 		tmpbuf[len] = '\0';
 		gvp = (GV**)hv_fetch(stash,tmpbuf,len,add);
-		gv = gvp ? *gvp : Nullgv;
+		gv = gvp ? *gvp : NULL;
 		if (gv && gv != (GV*)&PL_sv_undef) {
 		    if (SvTYPE(gv) != SVt_PVGV)
 			gv_init(gv, stash, tmpbuf, len, (add & GV_ADDMULTI));
@@ -716,53 +856,63 @@ Perl_gv_fetchpvn_flags(pTHX_ const char *nambeg, STRLEN full_len, I32 flags,
 		if (tmpbuf != smallbuf)
 		    Safefree(tmpbuf);
 		if (!gv || gv == (GV*)&PL_sv_undef)
-		    return Nullgv;
+		    return NULL;
 
 		if (!(stash = GvHV(gv)))
 		    stash = GvHV(gv) = newHV();
 
 		if (!HvNAME_get(stash))
-		    Perl_hv_name_set(aTHX_ stash, nambeg, namend - nambeg, 0);
+		    hv_name_set(stash, nambeg, name_cursor - nambeg, 0);
 	    }
 
-	    if (*namend == ':')
-		namend++;
-	    namend++;
-	    name = namend;
-	    if (!*name)
-		return gv ? gv : (GV*)*hv_fetch(PL_defstash, "main::", 6, TRUE);
+	    if (*name_cursor == ':')
+		name_cursor++;
+	    name_cursor++;
+	    name = name_cursor;
+	    if (name == name_end)
+		return gv ? gv : (GV*)*hv_fetchs(PL_defstash, "main::", TRUE);
 	}
     }
-    len = namend - name;
+    len = name_cursor - name;
 
     /* No stash in name, so see how we can default */
 
     if (!stash) {
-	if (isIDFIRST_lazy(name)) {
+    no_stash:
+	if (len && isIDFIRST_lazy(name)) {
 	    bool global = FALSE;
 
-	    /* name is always \0 terminated, and initial \0 wouldn't return
-	       true from isIDFIRST_lazy, so we know that name[1] is defined  */
-	    switch (name[1]) {
-	    case '\0':
+	    switch (len) {
+	    case 1:
 		if (*name == '_')
 		    global = TRUE;
 		break;
-	    case 'N':
-		if (strEQ(name, "INC") || strEQ(name, "ENV"))
+	    case 3:
+		if ((name[0] == 'I' && name[1] == 'N' && name[2] == 'C')
+		    || (name[0] == 'E' && name[1] == 'N' && name[2] == 'V')
+		    || (name[0] == 'S' && name[1] == 'I' && name[2] == 'G'))
 		    global = TRUE;
 		break;
-	    case 'I':
-		if (strEQ(name, "SIG"))
+	    case 4:
+		if (name[0] == 'A' && name[1] == 'R' && name[2] == 'G'
+		    && name[3] == 'V')
+		    global = TRUE;
+		break;
+	    case 5:
+		if (name[0] == 'S' && name[1] == 'T' && name[2] == 'D'
+		    && name[3] == 'I' && name[4] == 'N')
 		    global = TRUE;
 		break;
-	    case 'T':
-		if (strEQ(name, "STDIN") || strEQ(name, "STDOUT") ||
-		    strEQ(name, "STDERR"))
+	    case 6:
+		if ((name[0] == 'S' && name[1] == 'T' && name[2] == 'D')
+		    &&((name[3] == 'O' && name[4] == 'U' && name[5] == 'T')
+		       ||(name[3] == 'E' && name[4] == 'R' && name[5] == 'R')))
 		    global = TRUE;
 		break;
-	    case 'R':
-		if (strEQ(name, "ARGV") || strEQ(name, "ARGVOUT"))
+	    case 7:
+		if (name[0] == 'A' && name[1] == 'R' && name[2] == 'G'
+		    && name[3] == 'V' && name[4] == 'O' && name[5] == 'U'
+		    && name[6] == 'T')
 		    global = TRUE;
 		break;
 	    }
@@ -784,7 +934,7 @@ Perl_gv_fetchpvn_flags(pTHX_ const char *nambeg, STRLEN full_len, I32 flags,
 			*gvp == (GV*)&PL_sv_undef ||
 			SvTYPE(*gvp) != SVt_PVGV)
 		    {
-			stash = 0;
+			stash = NULL;
 		    }
 		    else if ((sv_type == SVt_PV   && !GvIMPORTED_SV(*gvp)) ||
 			     (sv_type == SVt_PVAV && !GvIMPORTED_AV(*gvp)) ||
@@ -796,7 +946,7 @@ Perl_gv_fetchpvn_flags(pTHX_ const char *nambeg, STRLEN full_len, I32 flags,
 			    name);
 			if (GvCVu(*gvp))
 			    Perl_warn(aTHX_ "\t(Did you mean &%s instead?)\n", name);
-			stash = 0;
+			stash = NULL;
 		    }
 		}
 	    }
@@ -811,37 +961,51 @@ Perl_gv_fetchpvn_flags(pTHX_ const char *nambeg, STRLEN full_len, I32 flags,
 
     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 ? "@"
 		  : sv_type == SVt_PVHV ? "%"
 		  : ""), name);
+	    GV *gv;
 	    if (USE_UTF8_IN_NAMES)
 		SvUTF8_on(err);
 	    qerror(err);
-	    stash = GvHV(gv_fetchpv("<none>::", GV_ADDMULTI, SVt_PVHV));
+	    gv = gv_fetchpvn_flags("<none>::", 8, GV_ADDMULTI, SVt_PVHV);
+	    if(!gv) {
+		/* symbol table under destruction */
+		return NULL;
+	    }	
+	    stash = GvHV(gv);
 	}
 	else
-	    return Nullgv;
+	    return NULL;
     }
 
     if (!SvREFCNT(stash))	/* symbol table under destruction */
-	return Nullgv;
+	return NULL;
 
     gvp = (GV**)hv_fetch(stash,name,len,add);
     if (!gvp || *gvp == (GV*)&PL_sv_undef)
-	return Nullgv;
+	return NULL;
     gv = *gvp;
     if (SvTYPE(gv) == SVt_PVGV) {
 	if (add) {
 	    GvMULTI_on(gv);
 	    gv_init_sv(gv, sv_type);
-	    if (*name=='!' && sv_type == SVt_PVHV && len==1)
-		require_errno(gv);
+	    if (sv_type == SVt_PVHV && len == 1 ) {
+	        if (*name == '!')
+		    require_tie_mod(gv, "!", newSVpvs("Errno"), "TIEHASH", 1);
+		else
+		if (*name == '-' || *name == '+') 
+		     require_tie_mod(gv, name, newSVpvs("re::Tie::Hash::NamedCapture"), "FETCH", 0);
+		
+            }		    
 	}
 	return gv;
-    } else if (add & GV_NOINIT) {
+    } else if (no_init) {
+	return gv;
+    } else if (no_expand && SvROK(gv)) {
 	return gv;
     }
 
@@ -860,6 +1024,7 @@ Perl_gv_fetchpvn_flags(pTHX_ const char *nambeg, STRLEN full_len, I32 flags,
     if (len > 1) {
 #ifndef EBCDIC
 	if (*name > 'V' ) {
+	    NOOP;
 	    /* 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
@@ -873,6 +1038,9 @@ Perl_gv_fetchpvn_flags(pTHX_ const char *nambeg, STRLEN full_len, I32 flags,
 		if (strEQ(name2, "RGV")) {
 		    IoFLAGS(GvIOn(gv)) |= IOf_ARGV|IOf_START;
 		}
+		else if (strEQ(name2, "RGVOUT")) {
+		    GvMULTI_on(gv);
+		}
 		break;
 	    case 'E':
 		if (strnEQ(name2, "XPORT", 5))
@@ -880,9 +1048,9 @@ Perl_gv_fetchpvn_flags(pTHX_ const char *nambeg, STRLEN full_len, I32 flags,
 		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);
+		    sv_magic((SV*)av, (SV*)gv, PERL_MAGIC_isa, NULL, 0);
 		    /* NOTE: No support for tied ISA */
 		    if ((add & GV_ADDMULTI) && strEQ(nambeg,"AnyDBM_File::ISA")
 			&& AvFILLp(av) == -1)
@@ -903,9 +1071,9 @@ Perl_gv_fetchpvn_flags(pTHX_ const char *nambeg, STRLEN full_len, I32 flags,
 		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);
+		    hv_magic(hv, NULL, PERL_MAGIC_overload);
 		}
 		break;
 	    case 'S':
@@ -913,16 +1081,15 @@ Perl_gv_fetchpvn_flags(pTHX_ const char *nambeg, STRLEN full_len, I32 flags,
 		    HV *hv;
 		    I32 i;
 		    if (!PL_psig_ptr) {
-			Newz(73, PL_psig_ptr,  SIG_SIZE, SV*);
-			Newz(73, PL_psig_name, SIG_SIZE, SV*);
-			Newz(73, PL_psig_pend, SIG_SIZE, int);
+			Newxz(PL_psig_ptr,  SIG_SIZE, SV*);
+			Newxz(PL_psig_name, SIG_SIZE, SV*);
+			Newxz(PL_psig_pend, SIG_SIZE, int);
 		    }
 		    GvMULTI_on(gv);
 		    hv = GvHVn(gv);
-		    hv_magic(hv, Nullgv, PERL_MAGIC_sig);
+		    hv_magic(hv, NULL, 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 * 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;
@@ -956,6 +1123,8 @@ Perl_gv_fetchpvn_flags(pTHX_ const char *nambeg, STRLEN full_len, I32 flags,
 		    goto ro_magicalize;
 		if (strEQ(name2, "TF8LOCALE"))
 		    goto ro_magicalize;
+		if (strEQ(name2, "TF8CACHE"))
+		    goto magicalize;
 		break;
 	    case '\027':	/* $^WARNING_BITS */
 		if (strEQ(name2, "ARNING_BITS"))
@@ -1000,57 +1169,72 @@ Perl_gv_fetchpvn_flags(pTHX_ const char *nambeg, STRLEN full_len, I32 flags,
 	    goto ro_magicalize;
 
 	case ':':
-	    sv_setpv(GvSV(gv),PL_chopset);
+	    sv_setpv(GvSVn(gv),PL_chopset);
 	    goto magicalize;
 
 	case '?':
 #ifdef COMPLEX_STATUS
-	    SvUPGRADE(GvSV(gv), SVt_PVLV);
+	    SvUPGRADE(GvSVn(gv), SVt_PVLV);
 #endif
 	    goto magicalize;
 
 	case '!':
+	GvMULTI_on(gv);    
+	    /* If %! has been used, automatically load Errno.pm. */
 
-	    /* If %! has been used, automatically load Errno.pm.
-	       The require will itself set errno, so in order to
-	       preserve its value we have to set up the magic
-	       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);
 
+            /* magicalization must be done before require_tie_mod is called */
 	    if (sv_type == SVt_PVHV)
-		require_errno(gv);
+		require_tie_mod(gv, "!", newSVpvs("Errno"), "TIEHASH", 1);
 
 	    break;
 	case '-':
-	{
-            AV* av = GvAVn(gv);
-            sv_magic((SV*)av, Nullsv, PERL_MAGIC_regdata, Nullch, 0);
-	    SvREADONLY_on(av);
-	    goto magicalize;
+	case '+':
+	GvMULTI_on(gv); /* no used once warnings here */
+        {
+            bool plus = (*name == '+');
+            SV *stashname = newSVpvs("re::Tie::Hash::NamedCapture");
+            AV* const av = GvAVn(gv);
+    	    HV *const hv = GvHVn(gv);
+    	    HV *const hv_tie = newHV();
+            SV *tie = newRV_noinc((SV*)hv_tie);
+
+            sv_bless(tie, gv_stashsv(stashname,1));
+            hv_magic(hv, (GV*)tie, PERL_MAGIC_tied);    
+            sv_magic((SV*)av, (plus ? (SV*)av : NULL), PERL_MAGIC_regdata, NULL, 0);
+            sv_magic(GvSVn(gv), (SV*)gv, PERL_MAGIC_sv, name, len);
+
+            if (plus)
+                SvREADONLY_on(GvSVn(gv));
+            else
+                Perl_hv_store(aTHX_ hv_tie, STR_WITH_LEN("all"), newSViv(1), 0);
+            
+            SvREADONLY_on(hv);
+            SvREADONLY_on(tie);
+            SvREADONLY_on(av);
+                
+            if (sv_type == SVt_PVHV) 
+                require_tie_mod(gv, name, stashname, "FETCH", 0);
+
+	    break;
 	}
 	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);
-            sv_magic((SV*)av, (SV*)av, PERL_MAGIC_regdata, Nullch, 0);
-	    SvREADONLY_on(av);
-	    /* FALL THROUGH */
-	}
+	case '\010':	/* $^H */
+	    {
+		HV *const hv = GvHVn(gv);
+		hv_magic(hv, NULL, PERL_MAGIC_hints);
+	    }
+	    goto magicalize;
 	case '\023':	/* $^S */
 	case '1':
 	case '2':
@@ -1062,7 +1246,7 @@ Perl_gv_fetchpvn_flags(pTHX_ const char *nambeg, STRLEN full_len, I32 flags,
 	case '8':
 	case '9':
 	ro_magicalize:
-	    SvREADONLY_on(GvSV(gv));
+	    SvREADONLY_on(GvSVn(gv));
 	    /* FALL THROUGH */
 	case '[':
 	case '^':
@@ -1082,7 +1266,6 @@ Perl_gv_fetchpvn_flags(pTHX_ const char *nambeg, STRLEN full_len, I32 flags,
 	case '\004':	/* $^D */
 	case '\005':	/* $^E */
 	case '\006':	/* $^F */
-	case '\010':	/* $^H */
 	case '\011':	/* $^I, NOT \t in EBCDIC */
 	case '\016':	/* $^N */
 	case '\017':	/* $^O */
@@ -1090,21 +1273,21 @@ Perl_gv_fetchpvn_flags(pTHX_ const char *nambeg, STRLEN full_len, I32 flags,
 	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_setpvn(GvSV(gv),"\f",1);
-	    PL_formfeed = GvSV(gv);
+	    sv_setpvn(GvSVn(gv),"\f",1);
+	    PL_formfeed = GvSVn(gv);
 	    break;
 	case ';':
-	    sv_setpvn(GvSV(gv),"\034",1);
+	    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);
+		upg_version(PL_patchlevel);
 	    GvSV(gv) = vnumify(PL_patchlevel);
 	    SvREADONLY_on(GvSV(gv));
 	    SvREFCNT_dec(sv);
@@ -1112,7 +1295,7 @@ Perl_gv_fetchpvn_flags(pTHX_ const char *nambeg, STRLEN full_len, I32 flags,
 	break;
 	case '\026':	/* $^V */
 	{
-	    SV * const sv = GvSV(gv);
+	    SV * const sv = GvSVn(gv);
 	    GvSV(gv) = new_version(PL_patchlevel);
 	    SvREADONLY_on(GvSV(gv));
 	    SvREFCNT_dec(sv);
@@ -1145,68 +1328,45 @@ Perl_gv_fullname4(pTHX_ SV *sv, const GV *gv, const char *prefix, bool keepmain)
 
     if (keepmain || strNE(name, "main")) {
 	sv_catpvn(sv,name,namelen);
-	sv_catpvn(sv,"::", 2);
+	sv_catpvs(sv,"::");
     }
     sv_catpvn(sv,GvNAME(gv),GvNAMELEN(gv));
 }
 
 void
-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, const GV *gv, const char *prefix, bool keepmain)
 {
-    const GV *egv = GvEGV(gv);
-    if (!egv)
-	egv = gv;
-    gv_fullname4(sv, egv, prefix, keepmain);
-}
-
-void
-Perl_gv_efullname3(pTHX_ SV *sv, const GV *gv, const char *prefix)
-{
-    gv_efullname4(sv, gv, prefix, TRUE);
-}
-
-/* compatibility with versions <= 5.003. */
-void
-Perl_gv_fullname(pTHX_ SV *sv, const GV *gv)
-{
-    gv_fullname3(sv, gv, sv == (const SV*)gv ? "*" : "");
-}
-
-/* compatibility with versions <= 5.003. */
-void
-Perl_gv_efullname(pTHX_ SV *sv, const GV *gv)
-{
-    gv_efullname3(sv, gv, sv == (const SV*)gv ? "*" : "");
+    const GV * const egv = GvEGV(gv);
+    gv_fullname4(sv, egv ? egv : gv, prefix, keepmain);
 }
 
 IO *
 Perl_newIO(pTHX)
 {
+    dVAR;
     GV *iogv;
-    IO * const io = (IO*)NEWSV(0,0);
+    IO * const io = (IO*)newSV(0);
 
     sv_upgrade((SV *)io,SVt_PVIO);
-    SvREFCNT(io) = 1;
+    /* This used to read SvREFCNT(io) = 1;
+       It's not clear why the reference count needed an explicit reset. NWC
+    */
+    assert (SvREFCNT(io) == 1);
     SvOBJECT_on(io);
     /* Clear the stashcache because a new IO could overrule a package name */
     hv_clear(PL_stashcache);
-    iogv = gv_fetchpv("FileHandle::", FALSE, SVt_PVHV);
+    iogv = gv_fetchpvs("FileHandle::", 0, 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);
+      iogv = gv_fetchpvs("IO::Handle::", GV_ADD, SVt_PVHV);
     SvSTASH_set(io, (HV*)SvREFCNT_inc(GvHV(iogv)));
     return io;
 }
 
 void
-Perl_gv_check(pTHX_ HV *stash)
+Perl_gv_check(pTHX_ const HV *stash)
 {
+    dVAR;
     register I32 i;
 
     if (!HvARRAY(stash))
@@ -1230,14 +1390,14 @@ Perl_gv_check(pTHX_ HV *stash)
 		file = GvFILE(gv);
 		/* performance hack: if filename is absolute and it's a standard
 		 * module, don't bother warning */
-		if (file
-		    && PERL_FILE_IS_ABSOLUTE(file)
 #ifdef MACOS_TRADITIONAL
-		    && (instr(file, ":lib:")
+#   define LIB_COMPONENT ":lib:"
 #else
-		    && (instr(file, "/lib/")
+#   define LIB_COMPONENT "/lib/"
 #endif
-		    || instr(file, ".pm")))
+		if (file
+		    && PERL_FILE_IS_ABSOLUTE(file)
+		    && (instr(file, LIB_COMPONENT) || instr(file, ".pm")))
 		{
 		    continue;
 		}
@@ -1258,8 +1418,9 @@ Perl_gv_check(pTHX_ HV *stash)
 GV *
 Perl_newGVgen(pTHX_ const char *pack)
 {
+    dVAR;
     return gv_fetchpv(Perl_form(aTHX_ "%s::_GEN_%ld", pack, (long)PL_gensym++),
-		      TRUE, SVt_PVGV);
+		      GV_ADD, SVt_PVGV);
 }
 
 /* hopefully this is only called on local symbol table entries */
@@ -1267,14 +1428,15 @@ Perl_newGVgen(pTHX_ const char *pack)
 GP*
 Perl_gp_ref(pTHX_ GP *gp)
 {
+    dVAR;
     if (!gp)
-	return (GP*)NULL;
+	return NULL;
     gp->gp_refcnt++;
     if (gp->gp_cv) {
 	if (gp->gp_cvgen) {
 	    /* multi-named GPs cannot be used for method cache */
 	    SvREFCNT_dec(gp->gp_cv);
-	    gp->gp_cv = Nullcv;
+	    gp->gp_cv = NULL;
 	    gp->gp_cvgen = 0;
 	}
 	else {
@@ -1288,9 +1450,10 @@ Perl_gp_ref(pTHX_ GP *gp)
 void
 Perl_gp_free(pTHX_ GV *gv)
 {
+    dVAR;
     GP* gp;
 
-    if (!gv || !(gp = GvGP(gv)))
+    if (!gv || !isGV_with_GP(gv) || !(gp = GvGP(gv)))
 	return;
     if (gp->gp_refcnt == 0) {
 	if (ckWARN_d(WARN_INTERNAL))
@@ -1306,11 +1469,14 @@ Perl_gp_free(pTHX_ GV *gv)
     if (--gp->gp_refcnt > 0) {
 	if (gp->gp_egv == gv)
 	    gp->gp_egv = 0;
+	GvGP(gv) = 0;
         return;
     }
 
-    if (gp->gp_sv) SvREFCNT_dec(gp->gp_sv);
-    if (gp->gp_av) SvREFCNT_dec(gp->gp_av);
+    if (gp->gp_file_hek)
+	unshare_hek(gp->gp_file_hek);
+    SvREFCNT_dec(gp->gp_sv);
+    SvREFCNT_dec(gp->gp_av);
     /* 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) {
@@ -1320,9 +1486,9 @@ Perl_gp_free(pTHX_ GV *gv)
 		      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);
-    if (gp->gp_form) SvREFCNT_dec(gp->gp_form);
+    SvREFCNT_dec(gp->gp_io);
+    SvREFCNT_dec(gp->gp_cv);
+    SvREFCNT_dec(gp->gp_form);
 
     Safefree(gp);
     GvGP(gv) = 0;
@@ -1331,16 +1497,16 @@ Perl_gp_free(pTHX_ GV *gv)
 int
 Perl_magic_freeovrld(pTHX_ SV *sv, MAGIC *mg)
 {
-    AMT *amtp = (AMT*)mg->mg_ptr;
-    (void)sv;
+    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];
-	    if (cv != Nullcv) {
+	    CV * const cv = amtp->table[i];
+	    if (cv) {
 		SvREFCNT_dec((SV *) cv);
-		amtp->table[i] = Nullcv;
+		amtp->table[i] = NULL;
 	    }
 	}
     }
@@ -1352,16 +1518,18 @@ 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;
+  dVAR;
+  MAGIC* const mg = mg_find((SV*)stash, PERL_MAGIC_overload_table);
   AMT amt;
 
-  if (mg && amtp->was_ok_am == PL_amagic_generation
-      && amtp->was_ok_sub == PL_sub_generation)
-      return (bool)AMT_OVERLOADED(amtp);
-  sv_unmagic((SV*)stash, PERL_MAGIC_overload_table);
+  if (mg) {
+      const AMT * const amtp = (AMT*)mg->mg_ptr;
+      if (amtp->was_ok_am == PL_amagic_generation
+	  && amtp->was_ok_sub == PL_sub_generation) {
+	  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_get(stash)) );
 
@@ -1374,28 +1542,32 @@ 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) {
+	NOOP;   /* Equivalent to !SvTRUE and !SvOK  */
+    }
+#endif
     else if (SvTRUE(sv))
 	amt.fallback=AMGfallYES;
     else if (SvOK(sv))
 	amt.fallback=AMGfallNEVER;
 
     for (i = 1; i < lim; i++)
-	amt.table[i] = Nullcv;
+	amt.table[i] = NULL;
     for (; i < NofAMmeth; i++) {
-	const char *cooky = PL_AMG_names[i];
+	const char * const cooky = PL_AMG_names[i];
 	/* Human-readable form, for debugging: */
-	const char *cp = (i >= DESTROY_amg ? cooky : AMG_id2name(i));
+	const char * const 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",
@@ -1419,18 +1591,18 @@ Perl_Gv_AMupdate(pTHX_ HV *stash)
 		/* 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;
+		GV *ngv = NULL;
+		SV *gvsv = GvSV(gv);
 
 		DEBUG_o( Perl_deb(aTHX_ "Resolving method \"%"SVf256\
 			"\" for overloaded \"%s\" in package \"%.256s\"\n",
-			     GvSV(gv), cp, hvname) );
-		if (!SvPOK(GvSV(gv))
-		    || !(ngv = gv_fetchmethod_autoload(stash, SvPVX_const(GvSV(gv)),
+			     (void*)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 * const name = SvPOK(gvsv) ?  SvPVX_const(gvsv) : "???";
+		    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"
@@ -1449,7 +1621,7 @@ Perl_Gv_AMupdate(pTHX_ HV *stash)
 	    cv = (CV*)gv;
 	    filled = 1;
 	}
-	amt.table[i]=(CV*)SvREFCNT_inc(cv);
+	amt.table[i]=(CV*)SvREFCNT_inc_simple(cv);
     }
     if (filled) {
       AMT_AMAGIC_on(&amt);
@@ -1472,17 +1644,19 @@ Perl_Gv_AMupdate(pTHX_ HV *stash)
 CV*
 Perl_gv_handler(pTHX_ HV *stash, I32 id)
 {
+    dVAR;
     MAGIC *mg;
     AMT *amtp;
 
     if (!stash || !HvNAME_get(stash))
-        return Nullcv;
+        return NULL;
     mg = mg_find((SV*)stash, PERL_MAGIC_overload_table);
     if (!mg) {
       do_update:
 	Gv_AMupdate(stash);
 	mg = mg_find((SV*)stash, PERL_MAGIC_overload_table);
     }
+    assert(mg);
     amtp = (AMT*)mg->mg_ptr;
     if ( amtp->was_ok_am != PL_amagic_generation
 	 || amtp->was_ok_sub != PL_sub_generation )
@@ -1494,7 +1668,7 @@ Perl_gv_handler(pTHX_ HV *stash, I32 id)
 	       "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, PL_AMG_names[id]);
+	    GV * const gv = gv_fetchmethod(stash, PL_AMG_names[id]);
 
 	    if (gv && GvCV(gv))
 		return GvCV(gv);
@@ -1502,7 +1676,7 @@ Perl_gv_handler(pTHX_ HV *stash, I32 id)
 	return ret;
     }
 
-    return Nullcv;
+    return NULL;
 }
 
 
@@ -1527,7 +1701,7 @@ Perl_amagic_call(pTHX_ SV *left, SV *right, int method, int flags)
       && (mg = mg_find((SV*)stash, PERL_MAGIC_overload_table))
       && (ocvp = cvp = (AMT_AMAGIC((AMT*)mg->mg_ptr)
 			? (oamtp = amtp = (AMT*)mg->mg_ptr)->table
-			: (CV **) NULL))
+			: NULL))
       && ((cv = cvp[off=method+assignshift])
 	  || (assign && amtp->fallback > AMGfallNEVER && /* fallback to
 						          * usual method */
@@ -1579,14 +1753,20 @@ Perl_amagic_call(pTHX_ SV *left, SV *right, int method, int flags)
 		  * SV* ref causes confusion with the interpreter variable of
 		  * the same name
 		  */
-	     SV* tmpRef=SvRV(left);
+	     SV* const tmpRef=SvRV(left);
 	     if (!SvROK(tmpRef) && SvTYPE(tmpRef) <= SVt_PVMG) {
 		/*
 		 * Just to be extra cautious.  Maybe in some
 		 * additional cases sv_setsv is safe, too.
 		 */
-		SV* newref = newSVsv(tmpRef);
+		SV* const newref = newSVsv(tmpRef);
 		SvOBJECT_on(newref);
+		/* As a bit of a source compatibility hack, SvAMAGIC() and
+		   friends dereference an RV, to behave the same was as when
+		   overloading was stored on the reference, not the referant.
+		   Hence we can't use SvAMAGIC_on()
+		*/
+		SvFLAGS(newref) |= SVf_AMAGIC;
 		SvSTASH_set(newref, (HV*)SvREFCNT_inc(SvSTASH(tmpRef)));
 		return newref;
 	     }
@@ -1595,13 +1775,13 @@ Perl_amagic_call(pTHX_ SV *left, SV *right, int method, int flags)
 	 case abs_amg:
 	   if ((cvp[off1=lt_amg] || cvp[off1=ncmp_amg])
 	       && ((cv = cvp[off=neg_amg]) || (cv = cvp[off=subtr_amg]))) {
-	     SV* nullsv=sv_2mortal(newSViv(0));
+	     SV* const nullsv=sv_2mortal(newSViv(0));
 	     if (off1==lt_amg) {
-	       SV* lessp = amagic_call(left,nullsv,
+	       SV* const lessp = amagic_call(left,nullsv,
 				       lt_amg,AMGf_noright);
 	       logic = SvTRUE(lessp);
 	     } else {
-	       SV* lessp = amagic_call(left,nullsv,
+	       SV* const lessp = amagic_call(left,nullsv,
 				       ncmp_amg,AMGf_noright);
 	       logic = (SvNV(lessp) < 0);
 	     }
@@ -1645,7 +1825,7 @@ Perl_amagic_call(pTHX_ SV *left, SV *right, int method, int flags)
 	       && (mg = mg_find((SV*)stash, PERL_MAGIC_overload_table))
 	       && (cvp = (AMT_AMAGIC((AMT*)mg->mg_ptr)
 			  ? (amtp = (AMT*)mg->mg_ptr)->table
-			  : (CV **) NULL))
+			  : NULL))
 	       && (cv = cvp[off=method])) { /* Method for right
 					     * argument found */
       lr=1;
@@ -1697,6 +1877,9 @@ Perl_amagic_call(pTHX_ SV *left, SV *right, int method, int flags)
 	notfound = 1; lr = -1;
       } else if (cvp && (cv=cvp[nomethod_amg])) {
 	notfound = 1; lr = 1;
+      } else if ((amtp && amtp->fallback >= AMGfallYES) && !DEBUG_o_TEST) {
+	/* Skip generating the "no method found" message.  */
+	return NULL;
       } else {
 	SV *msg;
 	if (off==-1) off=method;
@@ -1721,7 +1904,7 @@ Perl_amagic_call(pTHX_ SV *left, SV *right, int method, int flags)
 	if (amtp && amtp->fallback >= AMGfallYES) {
 	  DEBUG_o( Perl_deb(aTHX_ "%s", SvPVX_const(msg)) );
 	} else {
-	  Perl_croak(aTHX_ "%"SVf, msg);
+	  Perl_croak(aTHX_ "%"SVf, SVfARG(msg));
 	}
 	return NULL;
       }
@@ -1780,7 +1963,7 @@ Perl_amagic_call(pTHX_ SV *left, SV *right, int method, int flags)
     CATCH_SET(TRUE);
     Zero(&myop, 1, BINOP);
     myop.op_last = (OP *) &myop;
-    myop.op_next = Nullop;
+    myop.op_next = NULL;
     myop.op_flags = OPf_WANT_SCALAR | OPf_STACKED;
 
     PUSHSTACKi(PERLSI_OVERLOAD);
@@ -1865,7 +2048,7 @@ bool
 Perl_is_gv_magical_sv(pTHX_ SV *name, U32 flags)
 {
     STRLEN len;
-    const char *temp = SvPV_const(name, len);
+    const char * const temp = SvPV_const(name, len);
     return is_gv_magical(temp, len, flags);
 }
 
@@ -1889,7 +2072,9 @@ pointers returned by SvPV.
 bool
 Perl_is_gv_magical(pTHX_ const char *name, STRLEN len, U32 flags)
 {
-    (void)flags;
+    PERL_UNUSED_CONTEXT;
+    PERL_UNUSED_ARG(flags);
+
     if (len > 1) {
 	const char * const name1 = name + 1;
 	switch (*name) {
@@ -2006,6 +2191,26 @@ Perl_is_gv_magical(pTHX_ const char *name, STRLEN len, U32 flags)
     return FALSE;
 }
 
+void
+Perl_gv_name_set(pTHX_ GV *gv, const char *name, U32 len, U32 flags)
+{
+    dVAR;
+    U32 hash;
+
+    assert(name);
+    PERL_UNUSED_ARG(flags);
+
+    if (len > I32_MAX)
+	Perl_croak(aTHX_ "panic: gv name too long (%"UVuf")", (UV) len);
+
+    if (!(flags & GV_ADD) && GvNAME_HEK(gv)) {
+	unshare_hek(GvNAME_HEK(gv));
+    }
+
+    PERL_HASH(hash, name, len);
+    GvNAME_HEK(gv) = share_hek(name, len, hash);
+}
+
 /*
  * Local variables:
  * c-indentation-style: bsd