Re: new C3 MRO patch

[perl5.git] / gv.c

/*    gv.c
 *
 *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
 *    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.
 *
 */

/*
 *   'Mercy!' cried Gandalf.  'If the giving of information is to be the cure
 * of your inquisitiveness, I shall spend all the rest of my days answering
 * you.  What more do you want to know?'
 *   'The names of all the stars, and of all living things, and the whole
 * history of Middle-earth and Over-heaven and of the Sundering Seas,'
 * laughed Pippin.
 */

/*
=head1 GV Functions

A GV is a structure which corresponds to to a Perl typeglob, ie *foo.
It is a structure that holds a pointer to a scalar, an array, a hash etc,
corresponding to $foo, @foo, %foo.

GVs are usually found as values in stashes (symbol table hashes) where
Perl stores its global variables.

=cut
*/

#include "EXTERN.h"
#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(0);
    return gv;
}
#endif

GV *
Perl_gv_AVadd(pTHX_ register GV *gv)
{
    if (!gv || SvTYPE((SV*)gv) != SVt_PVGV)
	Perl_croak(aTHX_ "Bad symbol for array");
    if (!GvAV(gv))
	GvAV(gv) = newAV();
    return gv;
}

GV *
Perl_gv_HVadd(pTHX_ register GV *gv)
{
    if (!gv || SvTYPE((SV*)gv) != SVt_PVGV)
	Perl_croak(aTHX_ "Bad symbol for hash");
    if (!GvHV(gv))
	GvHV(gv) = newHV();
    return gv;
}

GV *
Perl_gv_IOadd(pTHX_ register GV *gv)
{
    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)) {
            Perl_croak(aTHX_ "Bad symbol for filehandle (GV is unique)");
        }
#endif
	GvIOp(gv) = newIO();
    }
    return gv;
}

GV *
Perl_gv_fetchfile(pTHX_ const char *name)
{
    return gv_fetchfile_flags(name, strlen(name), 0);
}

GV *
Perl_gv_fetchfile_flags(pTHX_ const char *const name, const STRLEN namelen,
			const U32 flags)
{
    dVAR;
    char smallbuf[128];
    char *tmpbuf;
    const STRLEN tmplen = namelen + 2;
    GV *gv;

    PERL_UNUSED_ARG(flags);

    if (!PL_defstash)
	return NULL;

    if (tmplen <= sizeof smallbuf)
	tmpbuf = smallbuf;
    else
	Newx(tmpbuf, tmplen, char);
    /* This is where the debugger's %{"::_<$filename"} hash is created */
    tmpbuf[0] = '_';
    tmpbuf[1] = '<';
    memcpy(tmpbuf + 2, name, namelen);
    gv = *(GV**)hv_fetch(PL_defstash, tmpbuf, tmplen, TRUE);
    if (!isGV(gv)) {
	gv_init(gv, PL_defstash, tmpbuf, tmplen, FALSE);
#ifdef PERL_DONT_CREATE_GVSV
	GvSV(gv) = newSVpvn(name, namelen);
#else
	sv_setpvn(GvSV(gv), name, namelen);
#endif
	if (PERLDB_LINE)
	    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->gp_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;
    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);
    }


    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_mutable(gv));
    }
    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. */
	ENTER;
	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 {
	    (void) start_subparse(0,0);	/* Create empty CV in compcv. */
	    GvCV(gv) = PL_compcv;
	}
	LEAVE;

        mro_method_changed_in(GvSTASH(gv)); /* sub Foo::bar($) { (shift) } sub ASDF::baz($); *ASDF::baz = \&Foo::bar */
	CvGV(GvCV(gv)) = gv;
	CvFILE_set_from_cop(GvCV(gv), PL_curcop);
	CvSTASH(GvCV(gv)) = PL_curstash;
	if (proto) {
	    sv_setpv((SV*)GvCV(gv), proto);
	    Safefree(proto);
	}
    }
}

STATIC void
S_gv_init_sv(pTHX_ GV *gv, I32 sv_type)
{
    switch (sv_type) {
    case SVt_PVIO:
	(void)GvIOn(gv);
	break;
    case SVt_PVAV:
	(void)GvAVn(gv);
	break;
    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:
	if(GvSVn(gv)) {
	    /* Work round what appears to be a bug in Sun C++ 5.8 2005/10/13
	       If we just cast GvSVn(gv) to void, it ignores evaluating it for
	       its side effect */
	}
#endif
    }
}

/*
=for apidoc gv_fetchmeth

Returns the glob with the given C<name> and a defined subroutine or
C<NULL>.  The glob lives in the given C<stash>, or in the stashes
accessible via @ISA and UNIVERSAL::.

The argument C<level> should be either 0 or -1.  If C<level==0>, as a
side-effect creates a glob with the given C<name> in the given C<stash>
which in the case of success contains an alias for the subroutine, and sets
up caching info for this glob.

This function grants C<"SUPER"> token as a postfix of the stash name. The
GV returned from C<gv_fetchmeth> may be a method cache entry, which is not
visible to Perl code.  So when calling C<call_sv>, you should not use
the GV directly; instead, you should use the method's CV, which can be
obtained from the GV with the C<GvCV> macro.

=cut
*/

/* NOTE: No support for tied ISA */

GV *
Perl_gv_fetchmeth(pTHX_ HV *stash, const char *name, STRLEN len, I32 level)
{
    dVAR;
    GV** gvp;
    AV* linear_av;
    SV** linear_svp;
    SV* linear_sv;
    HV* cstash;
    GV* candidate = NULL;
    CV* cand_cv = NULL;
    CV* old_cv;
    GV* topgv = NULL;
    const char *hvname;
    I32 create = (level >= 0) ? 1 : 0;
    I32 items;
    STRLEN packlen;
    U32 topgen_cmp;

    /* UNIVERSAL methods should be callable without a stash */
    if (!stash) {
	create = 0;  /* probably appropriate */
	if(!(stash = gv_stashpvs("UNIVERSAL", 0)))
	    return 0;
    }

    assert(stash);

    hvname = HvNAME_get(stash);
    if (!hvname)
      Perl_croak(aTHX_ "Can't use anonymous symbol table for method lookup");

    assert(hvname);
    assert(name);

    DEBUG_o( Perl_deb(aTHX_ "Looking for method %s in package %s\n",name,hvname) );

    topgen_cmp = HvMROMETA(stash)->sub_generation + PL_sub_generation;

    /* check locally for a real method or a cache entry */
    gvp = (GV**)hv_fetch(stash, name, len, create);
    if(gvp) {
        topgv = *gvp;
        assert(topgv);
        if (SvTYPE(topgv) != SVt_PVGV)
            gv_init(topgv, stash, name, len, TRUE);
        if ((cand_cv = GvCV(topgv))) {
            /* If genuine method or valid cache entry, use it */
            if (!GvCVGEN(topgv) || GvCVGEN(topgv) == topgen_cmp) {
                return topgv;
            }
            else {
                /* stale cache entry, junk it and move on */
	        SvREFCNT_dec(cand_cv);
	        GvCV(topgv) = cand_cv = NULL;
	        GvCVGEN(topgv) = 0;
            }
        }
        else if (GvCVGEN(topgv) == topgen_cmp) {
            /* cache indicates no such method definitively */
            return 0;
        }
    }

    packlen = HvNAMELEN_get(stash);
    if (packlen >= 7 && strEQ(hvname + packlen - 7, "::SUPER")) {
        HV* basestash;
        packlen -= 7;
        basestash = gv_stashpvn(hvname, packlen, GV_ADD);
        linear_av = mro_get_linear_isa(basestash);
    }
    else {
        linear_av = mro_get_linear_isa(stash); /* has ourselves at the top of the list */
    }

    linear_svp = AvARRAY(linear_av) + 1; /* skip over self */
    items = AvFILLp(linear_av); /* no +1, to skip over self */
    while (items--) {
        linear_sv = *linear_svp++;
        assert(linear_sv);
        cstash = gv_stashsv(linear_sv, 0);

        /* mg.c:Perl_magic_setisa sets the fake flag on packages it had
           to create that the user did not.  The "package" statement
           clears it.  We also check if there's anything in the symbol
           table at all, which would indicate a previously "fake" package
           where someone adding things via $Foo::Bar = 1 without ever
           using a "package" statement.
           This was all neccesary because magic_setisa needs a place to
           keep isarev information on packages that aren't yet defined,
           yet we still need to issue this warning when appropriate.
        */
        if (!cstash || (HvMROMETA(cstash)->fake && !HvFILL(cstash))) {
            if (ckWARN(WARN_MISC))
                Perl_warner(aTHX_ packWARN(WARN_MISC), "Can't locate package %"SVf" for @%s::ISA",
                    SVfARG(linear_sv), hvname);
            continue;
        }

        assert(cstash);

        gvp = (GV**)hv_fetch(cstash, name, len, 0);
        if (!gvp) continue;
        candidate = *gvp;
        assert(candidate);
        if (SvTYPE(candidate) != SVt_PVGV) gv_init(candidate, cstash, name, len, TRUE);
        if (SvTYPE(candidate) == SVt_PVGV && (cand_cv = GvCV(candidate)) && !GvCVGEN(candidate)) {
            /*
             * Found real method, cache method in topgv if:
             *  1. topgv has no synonyms (else inheritance crosses wires)
             *  2. method isn't a stub (else AUTOLOAD fails spectacularly)
             */
            if (topgv && (GvREFCNT(topgv) == 1) && (CvROOT(cand_cv) || CvXSUB(cand_cv))) {
                  if ((old_cv = GvCV(topgv))) SvREFCNT_dec(old_cv);
                  SvREFCNT_inc_simple_void_NN(cand_cv);
                  GvCV(topgv) = cand_cv;
                  GvCVGEN(topgv) = topgen_cmp;
            }
	    return candidate;
        }
    }

    /* Check UNIVERSAL without caching */
    if(level == 0 || level == -1) {
        candidate = gv_fetchmeth(NULL, name, len, 1);
        if(candidate) {
            cand_cv = GvCV(candidate);
            if (topgv && (GvREFCNT(topgv) == 1) && (CvROOT(cand_cv) || CvXSUB(cand_cv))) {
                  if ((old_cv = GvCV(topgv))) SvREFCNT_dec(old_cv);
                  SvREFCNT_inc_simple_void_NN(cand_cv);
                  GvCV(topgv) = cand_cv;
                  GvCVGEN(topgv) = topgen_cmp;
            }
            return candidate;
        }
    }

    if (topgv && GvREFCNT(topgv) == 1) {
        /* cache the fact that the method is not defined */
        GvCVGEN(topgv) = topgen_cmp;
    }

    return 0;
}

/*
=for apidoc gv_fetchmeth_autoload

Same as gv_fetchmeth(), but looks for autoloaded subroutines too.
Returns a glob for the subroutine.

For an autoloaded subroutine without a GV, will create a GV even
if C<level < 0>.  For an autoloaded subroutine without a stub, GvCV()
of the result may be zero.

=cut
*/

GV *
Perl_gv_fetchmeth_autoload(pTHX_ HV *stash, const char *name, STRLEN len, I32 level)
{
    GV *gv = gv_fetchmeth(stash, name, len, level);

    if (!gv) {
	CV *cv;
	GV **gvp;

	if (!stash)
	    return NULL;	/* UNIVERSAL::AUTOLOAD could cause trouble */
	if (len == S_autolen && strnEQ(name, S_autoload, S_autolen))
	    return NULL;
	if (!(gv = gv_fetchmeth(stash, S_autoload, S_autolen, FALSE)))
	    return NULL;
	cv = GvCV(gv);
	if (!(CvROOT(cv) || CvXSUB(cv)))
	    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 NULL;
	return *gvp;
    }
    return gv;
}

/*
=for apidoc gv_fetchmethod_autoload

Returns the glob which contains the subroutine to call to invoke the method
on the C<stash>.  In fact in the presence of autoloading this may be the
glob for "AUTOLOAD".  In this case the corresponding variable $AUTOLOAD is
already setup.

The third parameter of C<gv_fetchmethod_autoload> determines whether
AUTOLOAD lookup is performed if the given method is not present: non-zero
means yes, look for AUTOLOAD; zero means no, don't look for AUTOLOAD.
Calling C<gv_fetchmethod> is equivalent to calling C<gv_fetchmethod_autoload>
with a non-zero C<autoload> parameter.

These functions grant C<"SUPER"> token as a prefix of the method name. Note
that if you want to keep the returned glob for a long time, you need to
check for it being "AUTOLOAD", since at the later time the call may load a
different subroutine due to $AUTOLOAD changing its value. Use the glob
created via a side effect to do this.

These functions have the same side-effects and as C<gv_fetchmeth> with
C<level==0>.  C<name> should be writable if contains C<':'> or C<'
''>. The warning against passing the GV returned by C<gv_fetchmeth> to
C<call_sv> apply equally to these functions.

=cut
*/

GV *
Perl_gv_fetchmethod_autoload(pTHX_ HV *stash, const char *name, I32 autoload)
{
    dVAR;
    register const char *nend;
    const char *nsplit = NULL;
    GV* gv;
    HV* ostash = stash;

    if (stash && SvTYPE(stash) < SVt_PVHV)
	stash = NULL;

    for (nend = name; *nend; nend++) {
	if (*nend == '\'')
	    nsplit = nend;
	else if (*nend == ':' && *(nend + 1) == ':')
	    nsplit = ++nend;
    }
    if (nsplit) {
	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 * 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), GV_ADD);
	    DEBUG_o( Perl_deb(aTHX_ "Treating %s as %s::%s\n",
			 origname, HvNAME_get(stash), name) );
	}
	else {
            /* don't autovifify if ->NoSuchStash::method */
            stash = gv_stashpvn(origname, nsplit - origname, 0);

	    /* however, explicit calls to Pkg::SUPER::method may
	       happen, and may require autovivification to work */
	    if (!stash && (nsplit - origname) >= 7 &&
		strnEQ(nsplit - 7, "::SUPER", 7) &&
		gv_stashpvn(origname, nsplit - origname - 7, 0))
	      stash = gv_stashpvn(origname, nsplit - origname, GV_ADD);
	}
	ostash = stash;
    }

    gv = gv_fetchmeth(stash, name, nend - name, 0);
    if (!gv) {
	if (strEQ(name,"import") || strEQ(name,"unimport"))
	    gv = (GV*)&PL_sv_yes;
	else if (autoload)
	    gv = gv_autoload4(ostash, name, nend - name, TRUE);
    }
    else if (autoload) {
	CV* const cv = GvCV(gv);
	if (!CvROOT(cv) && !CvXSUB(cv)) {
	    GV* stubgv;
	    GV* autogv;

	    if (CvANON(cv))
		stubgv = gv;
	    else {
		stubgv = CvGV(cv);
		if (GvCV(stubgv) != cv)		/* orphaned import */
		    stubgv = gv;
	    }
	    autogv = gv_autoload4(GvSTASH(stubgv),
				  GvNAME(stubgv), GvNAMELEN(stubgv), TRUE);
	    if (autogv)
		gv = autogv;
	}
    }

    return gv;
}

GV*
Perl_gv_autoload4(pTHX_ HV *stash, const char *name, STRLEN len, I32 method)
{
    dVAR;
    GV* gv;
    CV* cv;
    HV* varstash;
    GV* vargv;
    SV* varsv;
    const char *packname = "";
    STRLEN packname_len = 0;

    if (len == S_autolen && strnEQ(name, S_autoload, S_autolen))
	return NULL;
    if (stash) {
	if (SvTYPE(stash) < SVt_PVHV) {
	    packname = SvPV_const((SV*)stash, packname_len);
	    stash = NULL;
	}
	else {
	    packname = HvNAME_get(stash);
	    packname_len = HvNAMELEN_get(stash);
	}
    }
    if (!(gv = gv_fetchmeth(stash, S_autoload, S_autolen, FALSE)))
	return NULL;
    cv = GvCV(gv);

    if (!(CvROOT(cv) || CvXSUB(cv)))
	return NULL;

    /*
     * Inheriting AUTOLOAD for non-methods works ... for now.
     */
    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 (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 '::',
         * pass along the same data via some unused fields in the CV
         */
        CvSTASH(cv) = stash;
        SvPV_set(cv, (char *)name); /* cast to lose constness warning */
        SvCUR_set(cv, len);
        return gv;
    }

    /*
     * Given &FOO::AUTOLOAD, set $FOO::AUTOLOAD to desired function name.
     * The subroutine's original name may not be "AUTOLOAD", so we don't
     * use that, but for lack of anything better we will use the sub's
     * original package to look up $AUTOLOAD.
     */
    varstash = GvSTASH(CvGV(cv));
    vargv = *(GV**)hv_fetch(varstash, S_autoload, S_autolen, TRUE);
    ENTER;

    if (!isGV(vargv)) {
	gv_init(vargv, varstash, S_autoload, S_autolen, FALSE);
#ifdef PERL_DONT_CREATE_GVSV
	GvSV(vargv) = newSV(0);
#endif
    }
    LEAVE;
    varsv = GvSVn(vargv);
    sv_setpvn(varsv, packname, packname_len);
    sv_catpvs(varsv, "::");
    sv_catpvn(varsv, name, len);
    return gv;
}


/* 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. Its refcount will be decremented.
 * "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 HV*
S_require_tie_mod(pTHX_ GV *gv, const char *varpv, SV* namesv, const char *methpv,const U32 flags)
{
    dVAR;
    HV* stash = gv_stashsv(namesv, 0);

    if (!stash || !(gv_fetchmethod(stash, methpv))) {
	SV *module = newSVsv(namesv);
	char varname = *varpv; /* varpv might be clobbered by load_module,
				  so save it. For the moment it's always
				  a single char. */
	dSP;
	ENTER;
	if ( flags & 1 )
	    save_scalar(gv);
	PUSHSTACKi(PERLSI_MAGIC);
	Perl_load_module(aTHX_ PERL_LOADMOD_NOIMPORT, module, NULL);
	POPSTACK;
	LEAVE;
	SPAGAIN;
	stash = gv_stashsv(namesv, 0);
	if (!stash)
	    Perl_croak(aTHX_ "panic: Can't use %%%c because %"SVf" is not available",
		    varname, SVfARG(namesv));
	else if (!gv_fetchmethod(stash, methpv))
	    Perl_croak(aTHX_ "panic: Can't use %%%c because %"SVf" does not support method %s",
		    varname, SVfARG(namesv), methpv);
    }
    SvREFCNT_dec(namesv);
    return stash;
}

/*
=for apidoc gv_stashpv

Returns a pointer to the stash for a specified package.  Uses C<strlen> to
determine the length of C<name>, then calls C<gv_stashpvn()>.

=cut
*/

HV*
Perl_gv_stashpv(pTHX_ const char *name, I32 create)
{
    return gv_stashpvn(name, strlen(name), create);
}

/*
=for apidoc gv_stashpvn

Returns a pointer to the stash for a specified package.  The C<namelen>
parameter indicates the length of the C<name>, in bytes.  C<flags> is passed
to C<gv_fetchpvn_flags()>, so if set to C<GV_ADD> then the package will be
created if it does not already exist.  If the package does not exist and
C<flags> is 0 (or any other setting that does not create packages) then NULL
is returned.


=cut
*/

HV*
Perl_gv_stashpvn(pTHX_ const char *name, U32 namelen, I32 flags)
{
    char smallbuf[128];
    char *tmpbuf;
    HV *stash;
    GV *tmpgv;

    if (namelen + 2 <= sizeof smallbuf)
	tmpbuf = smallbuf;
    else
	Newx(tmpbuf, namelen + 2, char);
    Copy(name,tmpbuf,namelen,char);
    tmpbuf[namelen++] = ':';
    tmpbuf[namelen++] = ':';
    tmpgv = gv_fetchpvn_flags(tmpbuf, namelen, flags, SVt_PVHV);
    if (tmpbuf != smallbuf)
	Safefree(tmpbuf);
    if (!tmpgv)
	return NULL;
    if (!GvHV(tmpgv))
	GvHV(tmpgv) = newHV();
    stash = GvHV(tmpgv);
    if (!HvNAME_get(stash))
	hv_name_set(stash, name, namelen, 0);
    return stash;
}

/*
=for apidoc gv_stashsv

Returns a pointer to the stash for a specified package.  See C<gv_stashpvn>.

=cut
*/

HV*
Perl_gv_stashsv(pTHX_ SV *sv, I32 flags)
{
    STRLEN len;
    const char * const ptr = SvPV_const(sv,len);
    return gv_stashpvn(ptr, len, flags);
}


GV *
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)
{
    dVAR;
    register const char *name = nambeg;
    register GV *gv = NULL;
    GV**gvp;
    I32 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 & ~GV_NOADD_MASK;
    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 (full_len > 2 && *name == '*' && isALPHA(name[1])) {
	/* accidental stringify on a GV? */
	name++;
    }

    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 NULL;

	    len = name_cursor - name;
	    if (len > 0) {
		char smallbuf[128];
		char *tmpbuf;

		if (len + 2 <= (I32)sizeof (smallbuf))
		    tmpbuf = smallbuf;
		else
		    Newx(tmpbuf, len+2, char);
		Copy(name, tmpbuf, len, char);
		tmpbuf[len++] = ':';
		tmpbuf[len++] = ':';
		gvp = (GV**)hv_fetch(stash,tmpbuf,len,add);
		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));
		    else
			GvMULTI_on(gv);
		}
		if (tmpbuf != smallbuf)
		    Safefree(tmpbuf);
		if (!gv || gv == (GV*)&PL_sv_undef)
		    return NULL;

		if (!(stash = GvHV(gv)))
		    stash = GvHV(gv) = newHV();

		if (!HvNAME_get(stash))
		    hv_name_set(stash, nambeg, name_cursor - nambeg, 0);
	    }

	    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 = name_cursor - name;

    /* No stash in name, so see how we can default */

    if (!stash) {
    no_stash:
	if (len && isIDFIRST_lazy(name)) {
	    bool global = FALSE;

	    switch (len) {
	    case 1:
		if (*name == '_')
		    global = TRUE;
		break;
	    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 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 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 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;
	    }

	    if (global)
		stash = PL_defstash;
	    else if (IN_PERL_COMPILETIME) {
		stash = PL_curstash;
		if (add && (PL_hints & HINT_STRICT_VARS) &&
		    sv_type != SVt_PVCV &&
		    sv_type != SVt_PVGV &&
		    sv_type != SVt_PVFM &&
		    sv_type != SVt_PVIO &&
		    !(len == 1 && sv_type == SVt_PV &&
		      (*name == 'a' || *name == 'b')) )
		{
		    gvp = (GV**)hv_fetch(stash,name,len,0);
		    if (!gvp ||
			*gvp == (GV*)&PL_sv_undef ||
			SvTYPE(*gvp) != SVt_PVGV)
		    {
			stash = NULL;
		    }
		    else if ((sv_type == SVt_PV   && !GvIMPORTED_SV(*gvp)) ||
			     (sv_type == SVt_PVAV && !GvIMPORTED_AV(*gvp)) ||
			     (sv_type == SVt_PVHV && !GvIMPORTED_HV(*gvp)) )
		    {
			Perl_warn(aTHX_ "Variable \"%c%s\" is not imported",
			    sv_type == SVt_PVAV ? '@' :
			    sv_type == SVt_PVHV ? '%' : '$',
			    name);
			if (GvCVu(*gvp))
			    Perl_warn(aTHX_ "\t(Did you mean &%s instead?)\n", name);
			stash = NULL;
		    }
		}
	    }
	    else
		stash = CopSTASH(PL_curcop);
	}
	else
	    stash = PL_defstash;
    }

    /* By this point we should have a stash and a name */

    if (!stash) {
	if (add) {
	    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);
	    gv = gv_fetchpvn_flags("<none>::", 8, GV_ADDMULTI, SVt_PVHV);
	    if(!gv) {
		/* symbol table under destruction */
		return NULL;
	    }	
	    stash = GvHV(gv);
	}
	else
	    return NULL;
    }

    if (!SvREFCNT(stash))	/* symbol table under destruction */
	return NULL;

    gvp = (GV**)hv_fetch(stash,name,len,add);
    if (!gvp || *gvp == (GV*)&PL_sv_undef)
	return NULL;
    gv = *gvp;
    if (SvTYPE(gv) == SVt_PVGV) {
	if (add) {
	    GvMULTI_on(gv);
	    gv_init_sv(gv, sv_type);
	    if (len == 1 && (sv_type == SVt_PVHV || sv_type == SVt_PVGV)) {
	        if (*name == '!')
		    require_tie_mod(gv, "!", newSVpvs("Errno"), "TIEHASH", 1);
		else if (*name == '-' || *name == '+')
		    require_tie_mod(gv, name, newSVpvs("Tie::Hash::NamedCapture"), "FETCH", 0);
	    }
	}
	return gv;
    } else if (no_init) {
	return gv;
    } else if (no_expand && SvROK(gv)) {
	return gv;
    }

    /* Adding a new symbol */

    if (add & GV_ADDWARN && ckWARN_d(WARN_INTERNAL))
	Perl_warner(aTHX_ packWARN(WARN_INTERNAL), "Had to create %s unexpectedly", nambeg);
    gv_init(gv, stash, name, len, add & GV_ADDMULTI);
    gv_init_sv(gv, sv_type);

    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' ) {
	    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
	       the common case of lower case variable names.  */
	} else
#endif
	{
	    const char * const name2 = name + 1;
	    switch (*name) {
	    case 'A':
		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))
		    GvMULTI_on(gv);
		break;
	    case 'I':
		if (strEQ(name2, "SA")) {
		    AV* const av = GvAVn(gv);
		    GvMULTI_on(gv);
		    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)
			{
			    const char *pname;
			    av_push(av, newSVpvn(pname = "NDBM_File",9));
			    gv_stashpvn(pname, 9, GV_ADD);
			    av_push(av, newSVpvn(pname = "DB_File",7));
			    gv_stashpvn(pname, 7, GV_ADD);
			    av_push(av, newSVpvn(pname = "GDBM_File",9));
			    gv_stashpvn(pname, 9, GV_ADD);
			    av_push(av, newSVpvn(pname = "SDBM_File",9));
			    gv_stashpvn(pname, 9, GV_ADD);
			    av_push(av, newSVpvn(pname = "ODBM_File",9));
			    gv_stashpvn(pname, 9, GV_ADD);
			}
		}
		break;
	    case 'O':
		if (strEQ(name2, "VERLOAD")) {
		    HV* const hv = GvHVn(gv);
		    GvMULTI_on(gv);
		    hv_magic(hv, NULL, PERL_MAGIC_overload);
		}
		break;
	    case 'S':
		if (strEQ(name2, "IG")) {
		    HV *hv;
		    I32 i;
		    if (!PL_psig_ptr) {
			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, NULL, PERL_MAGIC_sig);
		    for (i = 1; i < SIG_SIZE; i++) {
			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;
			PL_psig_name[i] = 0;
			PL_psig_pend[i] = 0;
		    }
		}
		break;
	    case 'V':
		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;
		break;
            case '\015':        /* $^MATCH */
                if (strEQ(name2, "ATCH"))
		    goto ro_magicalize;
	    case '\017':	/* $^OPEN */
		if (strEQ(name2, "PEN"))
		    goto magicalize;
		break;
	    case '\020':        /* $^PREMATCH  $^POSTMATCH */
	        if (strEQ(name2, "REMATCH") || strEQ(name2, "OSTMATCH"))
		    goto ro_magicalize;  
	    case '\024':	/* ${^TAINT} */
		if (strEQ(name2, "AINT"))
		    goto ro_magicalize;
		break;
	    case '\025':	/* ${^UNICODE}, ${^UTF8LOCALE} */
		if (strEQ(name2, "NICODE"))
		    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"))
		    goto magicalize;
		break;
	    case '1':
	    case '2':
	    case '3':
	    case '4':
	    case '5':
	    case '6':
	    case '7':
	    case '8':
	    case '9':
	    {
		/* ensures variable is only digits */
		/* ${"1foo"} fails this test (and is thus writeable) */
		/* added by japhy, but borrowed from is_gv_magical */
		const char *end = name + len;
		while (--end > name) {
		    if (!isDIGIT(*end)) return gv;
		}
		goto ro_magicalize;
	    }
	    }
	}
    } else {
	/* Names of length 1.  (Or 0. But name is NUL terminated, so that will
	   be case '\0' in this switch statement (ie a default case)  */
	switch (*name) {
	case '&':
	case '`':
	case '\'':
	    if (
		sv_type == SVt_PVAV ||
		sv_type == SVt_PVHV ||
		sv_type == SVt_PVCV ||
		sv_type == SVt_PVFM ||
		sv_type == SVt_PVIO
		) { break; }
	    PL_sawampersand = TRUE;
	    goto ro_magicalize;

	case ':':
	    sv_setpv(GvSVn(gv),PL_chopset);
	    goto magicalize;

	case '?':
#ifdef COMPLEX_STATUS
	    SvUPGRADE(GvSVn(gv), SVt_PVLV);
#endif
	    goto magicalize;

	case '!':
	    GvMULTI_on(gv);
	    /* If %! has been used, automatically load Errno.pm. */

	    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 || sv_type == SVt_PVGV)
		require_tie_mod(gv, "!", newSVpvs("Errno"), "TIEHASH", 1);

	    break;
	case '-':
	case '+':
	GvMULTI_on(gv); /* no used once warnings here */
        {
            AV* const av = GvAVn(gv);
	    SV* const avc = (*name == '+') ? (SV*)av : NULL;

	    sv_magic((SV*)av, avc, PERL_MAGIC_regdata, NULL, 0);
            sv_magic(GvSVn(gv), (SV*)gv, PERL_MAGIC_sv, name, len);
            if (avc)
                SvREADONLY_on(GvSVn(gv));
            SvREADONLY_on(av);

            if (sv_type == SVt_PVHV || sv_type == SVt_PVGV)
                require_tie_mod(gv, name, newSVpvs("Tie::Hash::NamedCapture"), "FETCH", 0);

            break;
	}
	case '*':
	case '#':
	    if (sv_type == SVt_PV && ckWARN2(WARN_DEPRECATED, WARN_SYNTAX))
		Perl_warner(aTHX_ packWARN2(WARN_DEPRECATED, WARN_SYNTAX),
			    "$%c is no longer supported", *name);
	    break;
	case '|':
	    sv_setiv(GvSVn(gv), (IV)(IoFLAGS(GvIOp(PL_defoutgv)) & IOf_FLUSH) != 0);
	    goto magicalize;

	case '\010':	/* $^H */
	    {
		HV *const hv = GvHVn(gv);
		hv_magic(hv, NULL, PERL_MAGIC_hints);
	    }
	    goto magicalize;
	case '\023':	/* $^S */
	case '1':
	case '2':
	case '3':
	case '4':
	case '5':
	case '6':
	case '7':
	case '8':
	case '9':
	ro_magicalize:
	    SvREADONLY_on(GvSVn(gv));
	    /* FALL THROUGH */
	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 '\011':	/* $^I, NOT \t in EBCDIC */
	case '\016':	/* $^N */
	case '\017':	/* $^O */
	case '\020':	/* $^P */
	case '\024':	/* $^T */
	case '\027':	/* $^W */
	magicalize:
	    sv_magic(GvSVn(gv), (SV*)gv, PERL_MAGIC_sv, name, len);
	    break;

	case '\014':	/* $^L */
	    sv_setpvn(GvSVn(gv),"\f",1);
	    PL_formfeed = GvSVn(gv);
	    break;
	case ';':
	    sv_setpvn(GvSVn(gv),"\034",1);
	    break;
	case ']':
	{
	    SV * const sv = GvSVn(gv);
	    if (!sv_derived_from(PL_patchlevel, "version"))
		upg_version(PL_patchlevel, TRUE);
	    GvSV(gv) = vnumify(PL_patchlevel);
	    SvREADONLY_on(GvSV(gv));
	    SvREFCNT_dec(sv);
	}
	break;
	case '\026':	/* $^V */
	{
	    SV * const sv = GvSVn(gv);
	    GvSV(gv) = new_version(PL_patchlevel);
	    SvREADONLY_on(GvSV(gv));
	    SvREFCNT_dec(sv);
	}
	break;
	}
    }
    return gv;
}

void
Perl_gv_fullname4(pTHX_ SV *sv, const GV *gv, const char *prefix, bool keepmain)
{
    const char *name;
    STRLEN namelen;
    const HV * const hv = GvSTASH(gv);
    if (!hv) {
	SvOK_off(sv);
	return;
    }
    sv_setpv(sv, prefix ? prefix : "");

    name = HvNAME_get(hv);
    if (name) {
	namelen = HvNAMELEN_get(hv);
    } else {
	name = "__ANON__";
	namelen = 8;
    }

    if (keepmain || strNE(name, "main")) {
	sv_catpvn(sv,name,namelen);
	sv_catpvs(sv,"::");
    }
    sv_catpvn(sv,GvNAME(gv),GvNAMELEN(gv));
}

void
Perl_gv_efullname4(pTHX_ SV *sv, const GV *gv, const char *prefix, bool keepmain)
{
    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_type(SVt_PVIO);
    /* 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_fetchpvs("FileHandle::", 0, SVt_PVHV);
    /* unless exists($main::{FileHandle}) and defined(%main::FileHandle::) */
    if (!(iogv && GvHV(iogv) && HvARRAY(GvHV(iogv))))
      iogv = gv_fetchpvs("IO::Handle::", GV_ADD, SVt_PVHV);
    SvSTASH_set(io, (HV*)SvREFCNT_inc(GvHV(iogv)));
    return io;
}

void
Perl_gv_check(pTHX_ const HV *stash)
{
    dVAR;
    register I32 i;

    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)))
	    {
		if (hv != PL_defstash && hv != stash)
		     gv_check(hv);              /* nested package */
	    }
	    else if (isALPHA(*HeKEY(entry))) {
                const char *file;
		gv = (GV*)HeVAL(entry);
		if (SvTYPE(gv) != SVt_PVGV || GvMULTI(gv))
		    continue;
		file = GvFILE(gv);
		CopLINE_set(PL_curcop, GvLINE(gv));
#ifdef USE_ITHREADS
		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_get(stash), GvNAME(gv));
	    }
	}
    }
}

GV *
Perl_newGVgen(pTHX_ const char *pack)
{
    dVAR;
    return gv_fetchpv(Perl_form(aTHX_ "%s::_GEN_%ld", pack, (long)PL_gensym++),
		      GV_ADD, SVt_PVGV);
}

/* hopefully this is only called on local symbol table entries */

GP*
Perl_gp_ref(pTHX_ GP *gp)
{
    dVAR;
    if (!gp)
	return NULL;
    gp->gp_refcnt++;
    if (gp->gp_cv) {
	if (gp->gp_cvgen) {
	    /* If the GP they asked for a reference to contains
               a method cache entry, clear it first, so that we
               don't infect them with our cached entry */
	    SvREFCNT_dec(gp->gp_cv);
	    gp->gp_cv = NULL;
	    gp->gp_cvgen = 0;
	}
        /* XXX if anyone finds a method cache regression with
           the "mro" stuff, turning this else block back on
           is probably the first place to look --blblack
        */
        /*
        else {
            PL_sub_generation++;
        }
        */
    }
    return gp;
}

void
Perl_gp_free(pTHX_ GV *gv)
{
    dVAR;
    GP* gp;

    if (!gv || !isGV_with_GP(gv) || !(gp = GvGP(gv)))
	return;
    if (gp->gp_refcnt == 0) {
	if (ckWARN_d(WARN_INTERNAL))
	    Perl_warner(aTHX_ packWARN(WARN_INTERNAL),
			"Attempt to free unreferenced glob pointers"
                        pTHX__FORMAT pTHX__VALUE);
        return;
    }
    if (gp->gp_cv) {
	/* Deleting the name of a subroutine invalidates method cache */
	PL_sub_generation++;
    }
    if (--gp->gp_refcnt > 0) {
	if (gp->gp_egv == gv)
	    gp->gp_egv = 0;
	GvGP(gv) = 0;
        return;
    }

    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) {
	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);
    }
    SvREFCNT_dec(gp->gp_io);
    SvREFCNT_dec(gp->gp_cv);
    SvREFCNT_dec(gp->gp_form);

    Safefree(gp);
    GvGP(gv) = 0;
}

int
Perl_magic_freeovrld(pTHX_ SV *sv, MAGIC *mg)
{
    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 * const cv = amtp->table[i];
	    if (cv) {
		SvREFCNT_dec((SV *) cv);
		amtp->table[i] = NULL;
	    }
	}
    }
 return 0;
}

/* Updates and caches the CV's */

bool
Perl_Gv_AMupdate(pTHX_ HV *stash)
{
  dVAR;
  MAGIC* const mg = mg_find((SV*)stash, PERL_MAGIC_overload_table);
  AMT amt;
  U32 newgen;

  newgen = PL_sub_generation + HvMROMETA(stash)->sub_generation;
  if (mg) {
      const AMT * const amtp = (AMT*)mg->mg_ptr;
      if (amtp->was_ok_am == PL_amagic_generation
	  && amtp->was_ok_sub == newgen) {
	  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)) );

  Zero(&amt,1,AMT);
  amt.was_ok_am = PL_amagic_generation;
  amt.was_ok_sub = newgen;
  amt.fallback = AMGfallNO;
  amt.flags = 0;

  {
    int filled = 0, have_ovl = 0;
    int i, lim = 1;

    /* Work with "fallback" key, which we assume to be first in PL_AMG_names */

    /* Try to find via inheritance. */
    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] = NULL;
    for (; i < NofAMmeth; i++) {
	const char * const cooky = PL_AMG_names[i];
	/* Human-readable form, for debugging: */
	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",
		     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.
	   Indeed, for inheritance A -> B -> C, if C overloads "+0",
	   then we could have created stubs for "(+0" in A and C too.
	   But if B overloads "bool", we may want to use it for
	   numifying instead of C's "+0". */
	if (i >= DESTROY_amg)
	    gv = Perl_gv_fetchmeth_autoload(aTHX_ stash, cooky, l, 0);
	else				/* Autoload taken care of below */
	    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 = 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 = NULL;
		SV *gvsv = GvSV(gv);

		DEBUG_o( Perl_deb(aTHX_ "Resolving method \"%"SVf256\
			"\" for overloaded \"%s\" in package \"%.256s\"\n",
			     (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"). */
		    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);
		}
		cv = GvCV(gv = ngv);
	    }
	    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)
		have_ovl = 1;
	} else if (gv) {		/* Autoloaded... */
	    cv = (CV*)gv;
	    filled = 1;
	}
	amt.table[i]=(CV*)SvREFCNT_inc_simple(cv);
    }
    if (filled) {
      AMT_AMAGIC_on(&amt);
      if (have_ovl)
	  AMT_OVERLOADED_on(&amt);
      sv_magic((SV*)stash, 0, PERL_MAGIC_overload_table,
						(char*)&amt, sizeof(AMT));
      return have_ovl;
    }
  }
  /* Here we have no table: */
  /* no_table: */
  AMT_AMAGIC_off(&amt);
  sv_magic((SV*)stash, 0, PERL_MAGIC_overload_table,
						(char*)&amt, sizeof(AMTS));
  return FALSE;
}


CV*
Perl_gv_handler(pTHX_ HV *stash, I32 id)
{
    dVAR;
    MAGIC *mg;
    AMT *amtp;
    U32 newgen;

    if (!stash || !HvNAME_get(stash))
        return NULL;

    newgen = PL_sub_generation + HvMROMETA(stash)->sub_generation;

    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 != newgen )
	goto do_update;
    if (AMT_AMAGIC(amtp)) {
	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 * const gv = gv_fetchmethod(stash, PL_AMG_names[id]);

	    if (gv && GvCV(gv))
		return GvCV(gv);
	}
	return ret;
    }

    return NULL;
}


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, 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
  HV* stash=NULL;
  if (!(AMGf_noleft & flags) && SvAMAGIC(left)
      && (stash = SvSTASH(SvRV(left)))
      && (mg = mg_find((SV*)stash, PERL_MAGIC_overload_table))
      && (ocvp = cvp = (AMT_AMAGIC((AMT*)mg->mg_ptr)
			? (oamtp = amtp = (AMT*)mg->mg_ptr)->table
			: NULL))
      && ((cv = cvp[off=method+assignshift])
	  || (assign && amtp->fallback > AMGfallNEVER && /* fallback to
						          * usual method */
		  (
#ifdef DEBUGGING
		   fl = 1,
#endif
		   cv = cvp[off=method])))) {
    lr = -1;			/* Call method for left argument */
  } else {
    if (cvp && amtp->fallback > AMGfallNEVER && flags & AMGf_unary) {
      int logic;

      /* look for substituted methods */
      /* In all the covered cases we should be called with assign==0. */
	 switch (method) {
	 case inc_amg:
	   force_cpy = 1;
	   if ((cv = cvp[off=add_ass_amg])
	       || ((cv = cvp[off = add_amg]) && (force_cpy = 0, postpr = 1))) {
	     right = &PL_sv_yes; lr = -1; assign = 1;
	   }
	   break;
	 case dec_amg:
	   force_cpy = 1;
	   if ((cv = cvp[off = subtr_ass_amg])
	       || ((cv = cvp[off = subtr_amg]) && (force_cpy = 0, postpr=1))) {
	     right = &PL_sv_yes; lr = -1; assign = 1;
	   }
	   break;
	 case bool__amg:
	   (void)((cv = cvp[off=numer_amg]) || (cv = cvp[off=string_amg]));
	   break;
	 case numer_amg:
	   (void)((cv = cvp[off=string_amg]) || (cv = cvp[off=bool__amg]));
	   break;
	 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 copy_amg:
	   {
	     /*
		  * SV* ref causes confusion with the interpreter variable of
		  * the same name
		  */
	     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* 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;
	     }
	   }
	   break;
	 case abs_amg:
	   if ((cvp[off1=lt_amg] || cvp[off1=ncmp_amg])
	       && ((cv = cvp[off=neg_amg]) || (cv = cvp[off=subtr_amg]))) {
	     SV* const nullsv=sv_2mortal(newSViv(0));
	     if (off1==lt_amg) {
	       SV* const lessp = amagic_call(left,nullsv,
				       lt_amg,AMGf_noright);
	       logic = SvTRUE(lessp);
	     } else {
	       SV* const lessp = amagic_call(left,nullsv,
				       ncmp_amg,AMGf_noright);
	       logic = (SvNV(lessp) < 0);
	     }
	     if (logic) {
	       if (off==subtr_amg) {
		 right = left;
		 left = nullsv;
		 lr = 1;
	       }
	     } else {
	       return left;
	     }
	   }
	   break;
	 case neg_amg:
	   if ((cv = cvp[off=subtr_amg])) {
	     right = left;
	     left = sv_2mortal(newSViv(0));
	     lr = 1;
	   }
	   break;
	 case int_amg:
	 case iter_amg:			/* XXXX Eventually should do to_gv. */
	     /* FAIL safe */
	     return NULL;	/* Delegate operation to standard mechanisms. */
	     break;
	 case to_sv_amg:
	 case to_av_amg:
	 case to_hv_amg:
	 case to_gv_amg:
	 case to_cv_amg:
	     /* FAIL safe */
	     return left;	/* Delegate operation to standard mechanisms. */
	     break;
	 default:
	   goto not_found;
	 }
	 if (!cv) goto not_found;
    } else if (!(AMGf_noright & flags) && SvAMAGIC(right)
	       && (stash = SvSTASH(SvRV(right)))
	       && (mg = mg_find((SV*)stash, PERL_MAGIC_overload_table))
	       && (cvp = (AMT_AMAGIC((AMT*)mg->mg_ptr)
			  ? (amtp = (AMT*)mg->mg_ptr)->table
			  : NULL))
	       && (cv = cvp[off=method])) { /* Method for right
					     * argument found */
      lr=1;
    } else if (((ocvp && oamtp->fallback > AMGfallNEVER
		 && (cvp=ocvp) && (lr = -1))
		|| (cvp && amtp->fallback > AMGfallNEVER && (lr=1)))
	       && !(flags & AMGf_unary)) {
				/* We look for substitution for
				 * comparison operations and
				 * concatenation */
      if (method==concat_amg || method==concat_ass_amg
	  || method==repeat_amg || method==repeat_ass_amg) {
	return NULL;		/* Delegate operation to string conversion */
      }
      off = -1;
      switch (method) {
	 case lt_amg:
	 case le_amg:
	 case gt_amg:
	 case ge_amg:
	 case eq_amg:
	 case ne_amg:
	   postpr = 1; off=ncmp_amg; break;
	 case slt_amg:
	 case sle_amg:
	 case sgt_amg:
	 case sge_amg:
	 case seq_amg:
	 case sne_amg:
	   postpr = 1; off=scmp_amg; break;
	 }
      if (off != -1) cv = cvp[off];
      if (!cv) {
	goto not_found;
      }
    } else {
    not_found:			/* No method found, either report or croak */
      switch (method) {
	 case lt_amg:
	 case le_amg:
	 case gt_amg:
	 case ge_amg:
	 case eq_amg:
	 case ne_amg:
	 case slt_amg:
	 case sle_amg:
	 case sgt_amg:
	 case sge_amg:
	 case seq_amg:
	 case sne_amg:
	   postpr = 0; break;
	 case to_sv_amg:
	 case to_av_amg:
	 case to_hv_amg:
	 case to_gv_amg:
	 case to_cv_amg:
	     /* FAIL safe */
	     return left;	/* Delegate operation to standard mechanisms. */
	     break;
      }
      if (ocvp && (cv=ocvp[nomethod_amg])) { /* Call report method */
	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;
	msg = sv_2mortal(Perl_newSVpvf(aTHX_
		      "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_get(SvSTASH(SvRV(left))):
		        "",
		      SvAMAGIC(right)?
		        ",\n\tright argument in overloaded package ":
		        (flags & AMGf_unary
			 ? ""
			 : ",\n\tright argument has no overloaded magic"),
		      SvAMAGIC(right)?
		        HvNAME_get(SvSTASH(SvRV(right))):
		        ""));
	if (amtp && amtp->fallback >= AMGfallYES) {
	  DEBUG_o( Perl_deb(aTHX_ "%s", SvPVX_const(msg)) );
	} else {
	  Perl_croak(aTHX_ "%"SVf, SVfARG(msg));
	}
	return NULL;
      }
      force_cpy = force_cpy || assign;
    }
  }
#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",
		     AMG_id2name(off),
		     method+assignshift==off? "" :
		     " (initially \"",
		     method+assignshift==off? "" :
		     AMG_id2name(method+assignshift),
		     method+assignshift==off? "" : "\")",
		     flags & AMGf_unary? "" :
		     lr==1 ? " for right argument": " for left argument",
		     flags & AMGf_unary? " for argument" : "",
		     stash ? HvNAME_get(stash) : "null",
		     fl? ",\n\tassignment variant used": "") );
  }
#endif
    /* Since we use shallow copy during assignment, we need
     * to dublicate the contents, probably calling user-supplied
     * version of copy operator
     */
    /* We need to copy in following cases:
     * a) Assignment form was called.
     * 		assignshift==1,  assign==T, method + 1 == off
     * b) Increment or decrement, called directly.
     * 		assignshift==0,  assign==0, method + 0 == off
     * c) Increment or decrement, translated to assignment add/subtr.
     * 		assignshift==0,  assign==T,
     *		force_cpy == T
     * d) Increment or decrement, translated to nomethod.
     * 		assignshift==0,  assign==0,
     *		force_cpy == T
     * e) Assignment form translated to nomethod.
     * 		assignshift==1,  assign==T, method + 1 != off
     *		force_cpy == T
     */
    /*	off is method, method+assignshift, or a result of opcode substitution.
     *	In the latter case assignshift==0, so only notfound case is important.
     */
  if (( (method + assignshift == off)
	&& (assign || (method == inc_amg) || (method == dec_amg)))
      || force_cpy)
    RvDEEPCP(left);
  {
    dSP;
    BINOP myop;
    SV* res;
    const bool oldcatch = CATCH_GET;

    CATCH_SET(TRUE);
    Zero(&myop, 1, BINOP);
    myop.op_last = (OP *) &myop;
    myop.op_next = NULL;
    myop.op_flags = OPf_WANT_SCALAR | OPf_STACKED;

    PUSHSTACKi(PERLSI_OVERLOAD);
    ENTER;
    SAVEOP();
    PL_op = (OP *) &myop;
    if (PERLDB_SUB && PL_curstash != PL_debstash)
	PL_op->op_private |= OPpENTERSUB_DB;
    PUTBACK;
    pp_pushmark();

    EXTEND(SP, notfound + 5);
    PUSHs(lr>0? right: left);
    PUSHs(lr>0? left: right);
    PUSHs( lr > 0 ? &PL_sv_yes : ( assign ? &PL_sv_undef : &PL_sv_no ));
    if (notfound) {
      PUSHs( sv_2mortal(newSVpv(AMG_id2name(method + assignshift),0)));
    }
    PUSHs((SV*)cv);
    PUTBACK;

    if ((PL_op = Perl_pp_entersub(aTHX)))
      CALLRUNOPS(aTHX);
    LEAVE;
    SPAGAIN;

    res=POPs;
    PUTBACK;
    POPSTACK;
    CATCH_SET(oldcatch);

    if (postpr) {
      int ans;
      switch (method) {
      case le_amg:
      case sle_amg:
	ans=SvIV(res)<=0; break;
      case lt_amg:
      case slt_amg:
	ans=SvIV(res)<0; break;
      case ge_amg:
      case sge_amg:
	ans=SvIV(res)>=0; break;
      case gt_amg:
      case sgt_amg:
	ans=SvIV(res)>0; break;
      case eq_amg:
      case seq_amg:
	ans=SvIV(res)==0; break;
      case ne_amg:
      case sne_amg:
	ans=SvIV(res)!=0; break;
      case inc_amg:
      case dec_amg:
	SvSetSV(left,res); return left;
      case not_amg:
	ans=!SvTRUE(res); break;
      default:
        ans=0; break;
      }
      return boolSV(ans);
    } else if (method==copy_amg) {
      if (!SvROK(res)) {
	Perl_croak(aTHX_ "Copy method did not return a reference");
      }
      return SvREFCNT_inc(SvRV(res));
    } else {
      return res;
    }
  }
}

/*
=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 * const 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.

Currently only useful internally when determining if a GV should be
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_ const char *name, STRLEN len, U32 flags)
{
    PERL_UNUSED_CONTEXT;
    PERL_UNUSED_ARG(flags);

    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':
	{
	    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;
	}
    }
    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
 * c-basic-offset: 4
 * indent-tabs-mode: t
 * End:
 *
 * ex: set ts=8 sts=4 sw=4 noet:
 */