forked from schacon/perl
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pad.c
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pad.c
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/* pad.c
*
* Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008
* 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.
*/
/*
* 'Anyway: there was this Mr. Frodo left an orphan and stranded, as you
* might say, among those queer Bucklanders, being brought up anyhow in
* Brandy Hall. A regular warren, by all accounts. Old Master Gorbadoc
* never had fewer than a couple of hundred relations in the place.
* Mr. Bilbo never did a kinder deed than when he brought the lad back
* to live among decent folk.' --the Gaffer
*
* [p.23 of _The Lord of the Rings_, I/i: "A Long-Expected Party"]
*/
/* XXX DAPM
* As of Sept 2002, this file is new and may be in a state of flux for
* a while. I've marked things I intent to come back and look at further
* with an 'XXX DAPM' comment.
*/
/*
=head1 Pad Data Structures
=for apidoc Amx|PADLIST *|CvPADLIST|CV *cv
CV's can have CvPADLIST(cv) set to point to a PADLIST. This is the CV's
scratchpad, which stores lexical variables and opcode temporary and
per-thread values.
For these purposes "formats" are a kind-of CV; eval""s are too (except they're
not callable at will and are always thrown away after the eval"" is done
executing). Require'd files are simply evals without any outer lexical
scope.
XSUBs don't have CvPADLIST set - dXSTARG fetches values from PL_curpad,
but that is really the callers pad (a slot of which is allocated by
every entersub).
The PADLIST has a C array where pads are stored.
The 0th entry of the PADLIST is a PADNAMELIST (which is actually just an
AV, but that may change) which represents the "names" or rather
the "static type information" for lexicals. The individual elements of a
PADNAMELIST are PADNAMEs (just SVs; but, again, that may change). Future
refactorings might stop the PADNAMELIST from being stored in the PADLIST's
array, so don't rely on it. See L</PadlistNAMES>.
The CvDEPTH'th entry of a PADLIST is a PAD (an AV) which is the stack frame
at that depth of recursion into the CV. The 0th slot of a frame AV is an
AV which is @_. Other entries are storage for variables and op targets.
Iterating over the PADNAMELIST iterates over all possible pad
items. Pad slots that are SVs_PADTMP (targets/GVs/constants) end up having
&PL_sv_undef "names" (see pad_alloc()).
Only my/our variable (SvPADMY/PADNAME_isOUR) slots get valid names.
The rest are op targets/GVs/constants which are statically allocated
or resolved at compile time. These don't have names by which they
can be looked up from Perl code at run time through eval"" the way
my/our variables can be. Since they can't be looked up by "name"
but only by their index allocated at compile time (which is usually
in PL_op->op_targ), wasting a name SV for them doesn't make sense.
The SVs in the names AV have their PV being the name of the variable.
xlow+1..xhigh inclusive in the NV union is a range of cop_seq numbers for
which the name is valid (accessed through the macros COP_SEQ_RANGE_LOW and
_HIGH). During compilation, these fields may hold the special value
PERL_PADSEQ_INTRO to indicate various stages:
COP_SEQ_RANGE_LOW _HIGH
----------------- -----
PERL_PADSEQ_INTRO 0 variable not yet introduced: { my ($x
valid-seq# PERL_PADSEQ_INTRO variable in scope: { my ($x)
valid-seq# valid-seq# compilation of scope complete: { my ($x) }
For typed lexicals name SV is SVt_PVMG and SvSTASH
points at the type. For C<our> lexicals, the type is also SVt_PVMG, with the
SvOURSTASH slot pointing at the stash of the associated global (so that
duplicate C<our> declarations in the same package can be detected). SvUVX is
sometimes hijacked to store the generation number during compilation.
If PADNAME_OUTER (SvFAKE) is set on the
name SV, then that slot in the frame AV is
a REFCNT'ed reference to a lexical from "outside". In this case,
the name SV does not use xlow and xhigh to store a cop_seq range, since it is
in scope throughout. Instead xhigh stores some flags containing info about
the real lexical (is it declared in an anon, and is it capable of being
instantiated multiple times?), and for fake ANONs, xlow contains the index
within the parent's pad where the lexical's value is stored, to make
cloning quicker.
If the 'name' is '&' the corresponding entry in the PAD
is a CV representing a possible closure.
(PADNAME_OUTER and name of '&' is not a
meaningful combination currently but could
become so if C<my sub foo {}> is implemented.)
Note that formats are treated as anon subs, and are cloned each time
write is called (if necessary).
The flag SVs_PADSTALE is cleared on lexicals each time the my() is executed,
and set on scope exit. This allows the
'Variable $x is not available' warning
to be generated in evals, such as
{ my $x = 1; sub f { eval '$x'} } f();
For state vars, SVs_PADSTALE is overloaded to mean 'not yet initialised'.
=for apidoc AmxU|PADNAMELIST *|PL_comppad_name
During compilation, this points to the array containing the names part
of the pad for the currently-compiling code.
=for apidoc AmxU|PAD *|PL_comppad
During compilation, this points to the array containing the values
part of the pad for the currently-compiling code. (At runtime a CV may
have many such value arrays; at compile time just one is constructed.)
At runtime, this points to the array containing the currently-relevant
values for the pad for the currently-executing code.
=for apidoc AmxU|SV **|PL_curpad
Points directly to the body of the L</PL_comppad> array.
(I.e., this is C<PAD_ARRAY(PL_comppad)>.)
=cut
*/
#include "EXTERN.h"
#define PERL_IN_PAD_C
#include "perl.h"
#include "keywords.h"
#define COP_SEQ_RANGE_LOW_set(sv,val) \
STMT_START { ((XPVNV*)SvANY(sv))->xnv_u.xpad_cop_seq.xlow = (val); } STMT_END
#define COP_SEQ_RANGE_HIGH_set(sv,val) \
STMT_START { ((XPVNV*)SvANY(sv))->xnv_u.xpad_cop_seq.xhigh = (val); } STMT_END
#define PARENT_PAD_INDEX_set(sv,val) \
STMT_START { ((XPVNV*)SvANY(sv))->xnv_u.xpad_cop_seq.xlow = (val); } STMT_END
#define PARENT_FAKELEX_FLAGS_set(sv,val) \
STMT_START { ((XPVNV*)SvANY(sv))->xnv_u.xpad_cop_seq.xhigh = (val); } STMT_END
/*
=for apidoc mx|void|pad_peg|const char *s
When PERL_MAD is enabled, this is a small no-op function that gets called
at the start of each pad-related function. It can be breakpointed to
track all pad operations. The parameter is a string indicating the type
of pad operation being performed.
=cut
*/
#ifdef PERL_MAD
void pad_peg(const char* s) {
static int pegcnt; /* XXX not threadsafe */
PERL_UNUSED_ARG(s);
PERL_ARGS_ASSERT_PAD_PEG;
pegcnt++;
}
#endif
/*
This is basically sv_eq_flags() in sv.c, but we avoid the magic
and bytes checking.
*/
static bool
sv_eq_pvn_flags(pTHX_ const SV *sv, const char* pv, const STRLEN pvlen, const U32 flags) {
if ( (SvUTF8(sv) & SVf_UTF8 ) != (flags & SVf_UTF8) ) {
const char *pv1 = SvPVX_const(sv);
STRLEN cur1 = SvCUR(sv);
const char *pv2 = pv;
STRLEN cur2 = pvlen;
if (PL_encoding) {
SV* svrecode = NULL;
if (SvUTF8(sv)) {
svrecode = newSVpvn(pv2, cur2);
sv_recode_to_utf8(svrecode, PL_encoding);
pv2 = SvPV_const(svrecode, cur2);
}
else {
svrecode = newSVpvn(pv1, cur1);
sv_recode_to_utf8(svrecode, PL_encoding);
pv1 = SvPV_const(svrecode, cur1);
}
SvREFCNT_dec(svrecode);
}
if (flags & SVf_UTF8)
return (bytes_cmp_utf8(
(const U8*)pv1, cur1,
(const U8*)pv2, cur2) == 0);
else
return (bytes_cmp_utf8(
(const U8*)pv2, cur2,
(const U8*)pv1, cur1) == 0);
}
else
return ((SvPVX_const(sv) == pv)
|| memEQ(SvPVX_const(sv), pv, pvlen));
}
/*
=for apidoc Am|PADLIST *|pad_new|int flags
Create a new padlist, updating the global variables for the
currently-compiling padlist to point to the new padlist. The following
flags can be OR'ed together:
padnew_CLONE this pad is for a cloned CV
padnew_SAVE save old globals on the save stack
padnew_SAVESUB also save extra stuff for start of sub
=cut
*/
PADLIST *
Perl_pad_new(pTHX_ int flags)
{
dVAR;
PADLIST *padlist;
PAD *padname, *pad;
PAD **ary;
ASSERT_CURPAD_LEGAL("pad_new");
/* XXX DAPM really need a new SAVEt_PAD which restores all or most
* vars (based on flags) rather than storing vals + addresses for
* each individually. Also see pad_block_start.
* XXX DAPM Try to see whether all these conditionals are required
*/
/* save existing state, ... */
if (flags & padnew_SAVE) {
SAVECOMPPAD();
if (! (flags & padnew_CLONE)) {
SAVESPTR(PL_comppad_name);
SAVEI32(PL_padix);
SAVEI32(PL_comppad_name_fill);
SAVEI32(PL_min_intro_pending);
SAVEI32(PL_max_intro_pending);
SAVEBOOL(PL_cv_has_eval);
if (flags & padnew_SAVESUB) {
SAVEBOOL(PL_pad_reset_pending);
}
}
}
/* XXX DAPM interestingly, PL_comppad_name_floor never seems to be
* saved - check at some pt that this is okay */
/* ... create new pad ... */
Newxz(padlist, 1, PADLIST);
pad = newAV();
if (flags & padnew_CLONE) {
/* XXX DAPM I dont know why cv_clone needs it
* doing differently yet - perhaps this separate branch can be
* dispensed with eventually ???
*/
AV * const a0 = newAV(); /* will be @_ */
av_store(pad, 0, MUTABLE_SV(a0));
AvREIFY_only(a0);
padname = (PAD *)SvREFCNT_inc_simple_NN(PL_comppad_name);
}
else {
padlist->xpadl_id = PL_padlist_generation++;
av_store(pad, 0, NULL);
padname = newAV();
}
/* Most subroutines never recurse, hence only need 2 entries in the padlist
array - names, and depth=1. The default for av_store() is to allocate
0..3, and even an explicit call to av_extend() with <3 will be rounded
up, so we inline the allocation of the array here. */
Newx(ary, 2, PAD *);
PadlistMAX(padlist) = 1;
PadlistARRAY(padlist) = ary;
ary[0] = padname;
ary[1] = pad;
/* ... then update state variables */
PL_comppad = pad;
PL_curpad = AvARRAY(pad);
if (! (flags & padnew_CLONE)) {
PL_comppad_name = padname;
PL_comppad_name_fill = 0;
PL_min_intro_pending = 0;
PL_padix = 0;
PL_cv_has_eval = 0;
}
DEBUG_X(PerlIO_printf(Perl_debug_log,
"Pad 0x%"UVxf"[0x%"UVxf"] new: compcv=0x%"UVxf
" name=0x%"UVxf" flags=0x%"UVxf"\n",
PTR2UV(PL_comppad), PTR2UV(PL_curpad), PTR2UV(PL_compcv),
PTR2UV(padname), (UV)flags
)
);
return (PADLIST*)padlist;
}
/*
=head1 Embedding Functions
=for apidoc cv_undef
Clear out all the active components of a CV. This can happen either
by an explicit C<undef &foo>, or by the reference count going to zero.
In the former case, we keep the CvOUTSIDE pointer, so that any anonymous
children can still follow the full lexical scope chain.
=cut
*/
void
Perl_cv_undef(pTHX_ CV *cv)
{
dVAR;
const PADLIST *padlist = CvPADLIST(cv);
bool const slabbed = !!CvSLABBED(cv);
PERL_ARGS_ASSERT_CV_UNDEF;
DEBUG_X(PerlIO_printf(Perl_debug_log,
"CV undef: cv=0x%"UVxf" comppad=0x%"UVxf"\n",
PTR2UV(cv), PTR2UV(PL_comppad))
);
if (CvFILE(cv) && CvDYNFILE(cv)) {
Safefree(CvFILE(cv));
}
CvFILE(cv) = NULL;
CvSLABBED_off(cv);
if (!CvISXSUB(cv) && CvROOT(cv)) {
if (SvTYPE(cv) == SVt_PVCV && CvDEPTH(cv))
Perl_croak(aTHX_ "Can't undef active subroutine");
ENTER;
PAD_SAVE_SETNULLPAD();
if (slabbed) OpslabREFCNT_dec_padok(OpSLAB(CvROOT(cv)));
op_free(CvROOT(cv));
CvROOT(cv) = NULL;
CvSTART(cv) = NULL;
LEAVE;
}
else if (slabbed && CvSTART(cv)) {
ENTER;
PAD_SAVE_SETNULLPAD();
/* discard any leaked ops */
opslab_force_free((OPSLAB *)CvSTART(cv));
CvSTART(cv) = NULL;
LEAVE;
}
#ifdef DEBUGGING
else if (slabbed) Perl_warn(aTHX_ "Slab leaked from cv %p", cv);
#endif
SvPOK_off(MUTABLE_SV(cv)); /* forget prototype */
sv_unmagic((SV *)cv, PERL_MAGIC_checkcall);
if (CvNAMED(cv)) CvNAME_HEK_set(cv, NULL);
else CvGV_set(cv, NULL);
/* This statement and the subsequence if block was pad_undef(). */
pad_peg("pad_undef");
if (padlist) {
I32 ix;
/* Free the padlist associated with a CV.
If parts of it happen to be current, we null the relevant PL_*pad*
global vars so that we don't have any dangling references left.
We also repoint the CvOUTSIDE of any about-to-be-orphaned inner
subs to the outer of this cv. */
DEBUG_X(PerlIO_printf(Perl_debug_log,
"Pad undef: cv=0x%"UVxf" padlist=0x%"UVxf" comppad=0x%"UVxf"\n",
PTR2UV(cv), PTR2UV(padlist), PTR2UV(PL_comppad))
);
/* detach any '&' anon children in the pad; if afterwards they
* are still live, fix up their CvOUTSIDEs to point to our outside,
* bypassing us. */
/* XXX DAPM for efficiency, we should only do this if we know we have
* children, or integrate this loop with general cleanup */
if (PL_phase != PERL_PHASE_DESTRUCT) { /* don't bother during global destruction */
CV * const outercv = CvOUTSIDE(cv);
const U32 seq = CvOUTSIDE_SEQ(cv);
PAD * const comppad_name = PadlistARRAY(padlist)[0];
SV ** const namepad = AvARRAY(comppad_name);
PAD * const comppad = PadlistARRAY(padlist)[1];
SV ** const curpad = AvARRAY(comppad);
for (ix = AvFILLp(comppad_name); ix > 0; ix--) {
SV * const namesv = namepad[ix];
if (namesv && namesv != &PL_sv_undef
&& *SvPVX_const(namesv) == '&')
{
CV * const innercv = MUTABLE_CV(curpad[ix]);
U32 inner_rc = SvREFCNT(innercv);
assert(inner_rc);
assert(SvTYPE(innercv) != SVt_PVFM);
if (SvREFCNT(comppad) < 2) { /* allow for /(?{ sub{} })/ */
curpad[ix] = NULL;
SvREFCNT_dec(innercv);
inner_rc--;
}
/* in use, not just a prototype */
if (inner_rc && (CvOUTSIDE(innercv) == cv)) {
assert(CvWEAKOUTSIDE(innercv));
/* don't relink to grandfather if he's being freed */
if (outercv && SvREFCNT(outercv)) {
CvWEAKOUTSIDE_off(innercv);
CvOUTSIDE(innercv) = outercv;
CvOUTSIDE_SEQ(innercv) = seq;
SvREFCNT_inc_simple_void_NN(outercv);
}
else {
CvOUTSIDE(innercv) = NULL;
}
}
}
}
}
ix = PadlistMAX(padlist);
while (ix > 0) {
PAD * const sv = PadlistARRAY(padlist)[ix--];
if (sv) {
if (sv == PL_comppad) {
PL_comppad = NULL;
PL_curpad = NULL;
}
SvREFCNT_dec(sv);
}
}
{
PAD * const sv = PadlistARRAY(padlist)[0];
if (sv == PL_comppad_name && SvREFCNT(sv) == 1)
PL_comppad_name = NULL;
SvREFCNT_dec(sv);
}
if (PadlistARRAY(padlist)) Safefree(PadlistARRAY(padlist));
Safefree(padlist);
CvPADLIST(cv) = NULL;
}
/* remove CvOUTSIDE unless this is an undef rather than a free */
if (!SvREFCNT(cv) && CvOUTSIDE(cv)) {
if (!CvWEAKOUTSIDE(cv))
SvREFCNT_dec(CvOUTSIDE(cv));
CvOUTSIDE(cv) = NULL;
}
if (CvCONST(cv)) {
SvREFCNT_dec(MUTABLE_SV(CvXSUBANY(cv).any_ptr));
CvCONST_off(cv);
}
if (CvISXSUB(cv) && CvXSUB(cv)) {
CvXSUB(cv) = NULL;
}
/* delete all flags except WEAKOUTSIDE and CVGV_RC, which indicate the
* ref status of CvOUTSIDE and CvGV, and ANON, which pp_entersub uses
* to choose an error message */
CvFLAGS(cv) &= (CVf_WEAKOUTSIDE|CVf_CVGV_RC|CVf_ANON);
}
/*
=for apidoc cv_forget_slab
When a CV has a reference count on its slab (CvSLABBED), it is responsible
for making sure it is freed. (Hence, no two CVs should ever have a
reference count on the same slab.) The CV only needs to reference the slab
during compilation. Once it is compiled and CvROOT attached, it has
finished its job, so it can forget the slab.
=cut
*/
void
Perl_cv_forget_slab(pTHX_ CV *cv)
{
const bool slabbed = !!CvSLABBED(cv);
OPSLAB *slab = NULL;
PERL_ARGS_ASSERT_CV_FORGET_SLAB;
if (!slabbed) return;
CvSLABBED_off(cv);
if (CvROOT(cv)) slab = OpSLAB(CvROOT(cv));
else if (CvSTART(cv)) slab = (OPSLAB *)CvSTART(cv);
#ifdef DEBUGGING
else if (slabbed) Perl_warn(aTHX_ "Slab leaked from cv %p", cv);
#endif
if (slab) {
#ifdef PERL_DEBUG_READONLY_OPS
const size_t refcnt = slab->opslab_refcnt;
#endif
OpslabREFCNT_dec(slab);
#ifdef PERL_DEBUG_READONLY_OPS
if (refcnt > 1) Slab_to_ro(slab);
#endif
}
}
/*
=for apidoc m|PADOFFSET|pad_alloc_name|SV *namesv|U32 flags|HV *typestash|HV *ourstash
Allocates a place in the currently-compiling
pad (via L<perlapi/pad_alloc>) and
then stores a name for that entry. I<namesv> is adopted and becomes the
name entry; it must already contain the name string and be sufficiently
upgraded. I<typestash> and I<ourstash> and the C<padadd_STATE> flag get
added to I<namesv>. None of the other
processing of L<perlapi/pad_add_name_pvn>
is done. Returns the offset of the allocated pad slot.
=cut
*/
static PADOFFSET
S_pad_alloc_name(pTHX_ SV *namesv, U32 flags, HV *typestash, HV *ourstash)
{
dVAR;
const PADOFFSET offset = pad_alloc(OP_PADSV, SVs_PADMY);
PERL_ARGS_ASSERT_PAD_ALLOC_NAME;
ASSERT_CURPAD_ACTIVE("pad_alloc_name");
if (typestash) {
assert(SvTYPE(namesv) == SVt_PVMG);
SvPAD_TYPED_on(namesv);
SvSTASH_set(namesv, MUTABLE_HV(SvREFCNT_inc_simple_NN(MUTABLE_SV(typestash))));
}
if (ourstash) {
SvPAD_OUR_on(namesv);
SvOURSTASH_set(namesv, ourstash);
SvREFCNT_inc_simple_void_NN(ourstash);
}
else if (flags & padadd_STATE) {
SvPAD_STATE_on(namesv);
}
av_store(PL_comppad_name, offset, namesv);
return offset;
}
/*
=for apidoc Am|PADOFFSET|pad_add_name_pvn|const char *namepv|STRLEN namelen|U32 flags|HV *typestash|HV *ourstash
Allocates a place in the currently-compiling pad for a named lexical
variable. Stores the name and other metadata in the name part of the
pad, and makes preparations to manage the variable's lexical scoping.
Returns the offset of the allocated pad slot.
I<namepv>/I<namelen> specify the variable's name, including leading sigil.
If I<typestash> is non-null, the name is for a typed lexical, and this
identifies the type. If I<ourstash> is non-null, it's a lexical reference
to a package variable, and this identifies the package. The following
flags can be OR'ed together:
padadd_OUR redundantly specifies if it's a package var
padadd_STATE variable will retain value persistently
padadd_NO_DUP_CHECK skip check for lexical shadowing
=cut
*/
PADOFFSET
Perl_pad_add_name_pvn(pTHX_ const char *namepv, STRLEN namelen,
U32 flags, HV *typestash, HV *ourstash)
{
dVAR;
PADOFFSET offset;
SV *namesv;
bool is_utf8;
PERL_ARGS_ASSERT_PAD_ADD_NAME_PVN;
if (flags & ~(padadd_OUR|padadd_STATE|padadd_NO_DUP_CHECK|padadd_UTF8_NAME))
Perl_croak(aTHX_ "panic: pad_add_name_pvn illegal flag bits 0x%" UVxf,
(UV)flags);
namesv = newSV_type((ourstash || typestash) ? SVt_PVMG : SVt_PVNV);
if ((is_utf8 = ((flags & padadd_UTF8_NAME) != 0))) {
namepv = (const char*)bytes_from_utf8((U8*)namepv, &namelen, &is_utf8);
}
sv_setpvn(namesv, namepv, namelen);
if (is_utf8) {
flags |= padadd_UTF8_NAME;
SvUTF8_on(namesv);
}
else
flags &= ~padadd_UTF8_NAME;
if ((flags & padadd_NO_DUP_CHECK) == 0) {
/* check for duplicate declaration */
pad_check_dup(namesv, flags & padadd_OUR, ourstash);
}
offset = pad_alloc_name(namesv, flags & ~padadd_UTF8_NAME, typestash, ourstash);
/* not yet introduced */
COP_SEQ_RANGE_LOW_set(namesv, PERL_PADSEQ_INTRO);
COP_SEQ_RANGE_HIGH_set(namesv, 0);
if (!PL_min_intro_pending)
PL_min_intro_pending = offset;
PL_max_intro_pending = offset;
/* if it's not a simple scalar, replace with an AV or HV */
assert(SvTYPE(PL_curpad[offset]) == SVt_NULL);
assert(SvREFCNT(PL_curpad[offset]) == 1);
if (namelen != 0 && *namepv == '@')
sv_upgrade(PL_curpad[offset], SVt_PVAV);
else if (namelen != 0 && *namepv == '%')
sv_upgrade(PL_curpad[offset], SVt_PVHV);
else if (namelen != 0 && *namepv == '&')
sv_upgrade(PL_curpad[offset], SVt_PVCV);
assert(SvPADMY(PL_curpad[offset]));
DEBUG_Xv(PerlIO_printf(Perl_debug_log,
"Pad addname: %ld \"%s\" new lex=0x%"UVxf"\n",
(long)offset, SvPVX(namesv),
PTR2UV(PL_curpad[offset])));
return offset;
}
/*
=for apidoc Am|PADOFFSET|pad_add_name_pv|const char *name|U32 flags|HV *typestash|HV *ourstash
Exactly like L</pad_add_name_pvn>, but takes a nul-terminated string
instead of a string/length pair.
=cut
*/
PADOFFSET
Perl_pad_add_name_pv(pTHX_ const char *name,
const U32 flags, HV *typestash, HV *ourstash)
{
PERL_ARGS_ASSERT_PAD_ADD_NAME_PV;
return pad_add_name_pvn(name, strlen(name), flags, typestash, ourstash);
}
/*
=for apidoc Am|PADOFFSET|pad_add_name_sv|SV *name|U32 flags|HV *typestash|HV *ourstash
Exactly like L</pad_add_name_pvn>, but takes the name string in the form
of an SV instead of a string/length pair.
=cut
*/
PADOFFSET
Perl_pad_add_name_sv(pTHX_ SV *name, U32 flags, HV *typestash, HV *ourstash)
{
char *namepv;
STRLEN namelen;
PERL_ARGS_ASSERT_PAD_ADD_NAME_SV;
namepv = SvPV(name, namelen);
if (SvUTF8(name))
flags |= padadd_UTF8_NAME;
return pad_add_name_pvn(namepv, namelen, flags, typestash, ourstash);
}
/*
=for apidoc Amx|PADOFFSET|pad_alloc|I32 optype|U32 tmptype
Allocates a place in the currently-compiling pad,
returning the offset of the allocated pad slot.
No name is initially attached to the pad slot.
I<tmptype> is a set of flags indicating the kind of pad entry required,
which will be set in the value SV for the allocated pad entry:
SVs_PADMY named lexical variable ("my", "our", "state")
SVs_PADTMP unnamed temporary store
I<optype> should be an opcode indicating the type of operation that the
pad entry is to support. This doesn't affect operational semantics,
but is used for debugging.
=cut
*/
/* XXX DAPM integrate alloc(), add_name() and add_anon(),
* or at least rationalise ??? */
PADOFFSET
Perl_pad_alloc(pTHX_ I32 optype, U32 tmptype)
{
dVAR;
SV *sv;
I32 retval;
PERL_UNUSED_ARG(optype);
ASSERT_CURPAD_ACTIVE("pad_alloc");
if (AvARRAY(PL_comppad) != PL_curpad)
Perl_croak(aTHX_ "panic: pad_alloc, %p!=%p",
AvARRAY(PL_comppad), PL_curpad);
if (PL_pad_reset_pending)
pad_reset();
if (tmptype & SVs_PADMY) {
/* For a my, simply push a null SV onto the end of PL_comppad. */
sv = *av_fetch(PL_comppad, AvFILLp(PL_comppad) + 1, TRUE);
retval = AvFILLp(PL_comppad);
}
else {
/* For a tmp, scan the pad from PL_padix upwards
* for a slot which has no name and no active value.
*/
SV * const * const names = AvARRAY(PL_comppad_name);
const SSize_t names_fill = AvFILLp(PL_comppad_name);
for (;;) {
/*
* "foreach" index vars temporarily become aliases to non-"my"
* values. Thus we must skip, not just pad values that are
* marked as current pad values, but also those with names.
*/
/* HVDS why copy to sv here? we don't seem to use it */
if (++PL_padix <= names_fill &&
(sv = names[PL_padix]) && sv != &PL_sv_undef)
continue;
sv = *av_fetch(PL_comppad, PL_padix, TRUE);
if (!(SvFLAGS(sv) & (SVs_PADTMP | SVs_PADMY)) &&
!IS_PADGV(sv) && !IS_PADCONST(sv))
break;
}
retval = PL_padix;
}
SvFLAGS(sv) |= tmptype;
PL_curpad = AvARRAY(PL_comppad);
DEBUG_X(PerlIO_printf(Perl_debug_log,
"Pad 0x%"UVxf"[0x%"UVxf"] alloc: %ld for %s\n",
PTR2UV(PL_comppad), PTR2UV(PL_curpad), (long) retval,
PL_op_name[optype]));
#ifdef DEBUG_LEAKING_SCALARS
sv->sv_debug_optype = optype;
sv->sv_debug_inpad = 1;
#endif
return (PADOFFSET)retval;
}
/*
=for apidoc Am|PADOFFSET|pad_add_anon|CV *func|I32 optype
Allocates a place in the currently-compiling pad (via L</pad_alloc>)
for an anonymous function that is lexically scoped inside the
currently-compiling function.
The function I<func> is linked into the pad, and its C<CvOUTSIDE> link
to the outer scope is weakened to avoid a reference loop.
One reference count is stolen, so you may need to do C<SvREFCNT_inc(func)>.
I<optype> should be an opcode indicating the type of operation that the
pad entry is to support. This doesn't affect operational semantics,
but is used for debugging.
=cut
*/
PADOFFSET
Perl_pad_add_anon(pTHX_ CV* func, I32 optype)
{
dVAR;
PADOFFSET ix;
SV* const name = newSV_type(SVt_PVNV);
PERL_ARGS_ASSERT_PAD_ADD_ANON;
pad_peg("add_anon");
sv_setpvs(name, "&");
/* These two aren't used; just make sure they're not equal to
* PERL_PADSEQ_INTRO */
COP_SEQ_RANGE_LOW_set(name, 0);
COP_SEQ_RANGE_HIGH_set(name, 0);
ix = pad_alloc(optype, SVs_PADMY);
av_store(PL_comppad_name, ix, name);
/* XXX DAPM use PL_curpad[] ? */
if (SvTYPE(func) == SVt_PVCV || !CvOUTSIDE(func))
av_store(PL_comppad, ix, (SV*)func);
else {
SV *rv = newRV_noinc((SV *)func);
sv_rvweaken(rv);
assert (SvTYPE(func) == SVt_PVFM);
av_store(PL_comppad, ix, rv);
}
SvPADMY_on((SV*)func);
/* to avoid ref loops, we never have parent + child referencing each
* other simultaneously */
if (CvOUTSIDE(func) && SvTYPE(func) == SVt_PVCV) {
assert(!CvWEAKOUTSIDE(func));
CvWEAKOUTSIDE_on(func);
SvREFCNT_dec(CvOUTSIDE(func));
}
return ix;
}
/*
=for apidoc pad_check_dup
Check for duplicate declarations: report any of:
* a my in the current scope with the same name;
* an our (anywhere in the pad) with the same name and the
same stash as C<ourstash>
C<is_our> indicates that the name to check is an 'our' declaration.
=cut
*/
STATIC void
S_pad_check_dup(pTHX_ SV *name, U32 flags, const HV *ourstash)
{
dVAR;
SV **svp;
PADOFFSET top, off;
const U32 is_our = flags & padadd_OUR;
PERL_ARGS_ASSERT_PAD_CHECK_DUP;
ASSERT_CURPAD_ACTIVE("pad_check_dup");
assert((flags & ~padadd_OUR) == 0);
if (AvFILLp(PL_comppad_name) < 0 || !ckWARN(WARN_MISC))
return; /* nothing to check */
svp = AvARRAY(PL_comppad_name);
top = AvFILLp(PL_comppad_name);
/* check the current scope */
/* XXX DAPM - why the (I32) cast - shouldn't we ensure they're the same
* type ? */
for (off = top; (I32)off > PL_comppad_name_floor; off--) {
SV * const sv = svp[off];
if (sv
&& sv != &PL_sv_undef
&& !SvFAKE(sv)
&& ( COP_SEQ_RANGE_LOW(sv) == PERL_PADSEQ_INTRO
|| COP_SEQ_RANGE_HIGH(sv) == PERL_PADSEQ_INTRO)
&& sv_eq(name, sv))
{
if (is_our && (SvPAD_OUR(sv)))
break; /* "our" masking "our" */
/* diag_listed_as: "%s" variable %s masks earlier declaration in same %s */
Perl_warner(aTHX_ packWARN(WARN_MISC),
"\"%s\" %s %"SVf" masks earlier declaration in same %s",
(is_our ? "our" : PL_parser->in_my == KEY_my ? "my" : "state"),
*SvPVX(sv) == '&' ? "subroutine" : "variable",
sv,
(COP_SEQ_RANGE_HIGH(sv) == PERL_PADSEQ_INTRO
? "scope" : "statement"));
--off;
break;
}
}
/* check the rest of the pad */
if (is_our) {
while (off > 0) {
SV * const sv = svp[off];
if (sv
&& sv != &PL_sv_undef
&& !SvFAKE(sv)
&& ( COP_SEQ_RANGE_LOW(sv) == PERL_PADSEQ_INTRO
|| COP_SEQ_RANGE_HIGH(sv) == PERL_PADSEQ_INTRO)
&& SvOURSTASH(sv) == ourstash
&& sv_eq(name, sv))
{
Perl_warner(aTHX_ packWARN(WARN_MISC),
"\"our\" variable %"SVf" redeclared", sv);
if ((I32)off <= PL_comppad_name_floor)
Perl_warner(aTHX_ packWARN(WARN_MISC),
"\t(Did you mean \"local\" instead of \"our\"?)\n");
break;
}
--off;
}
}
}
/*
=for apidoc Am|PADOFFSET|pad_findmy_pvn|const char *namepv|STRLEN namelen|U32 flags
Given the name of a lexical variable, find its position in the
currently-compiling pad.
I<namepv>/I<namelen> specify the variable's name, including leading sigil.
I<flags> is reserved and must be zero.
If it is not in the current pad but appears in the pad of any lexically
enclosing scope, then a pseudo-entry for it is added in the current pad.
Returns the offset in the current pad,
or C<NOT_IN_PAD> if no such lexical is in scope.
=cut
*/
PADOFFSET
Perl_pad_findmy_pvn(pTHX_ const char *namepv, STRLEN namelen, U32 flags)
{
dVAR;
SV *out_sv;
int out_flags;
I32 offset;
const AV *nameav;
SV **name_svp;
PERL_ARGS_ASSERT_PAD_FINDMY_PVN;
pad_peg("pad_findmy_pvn");
if (flags & ~padadd_UTF8_NAME)
Perl_croak(aTHX_ "panic: pad_findmy_pvn illegal flag bits 0x%" UVxf,
(UV)flags);
if (flags & padadd_UTF8_NAME) {
bool is_utf8 = TRUE;
namepv = (const char*)bytes_from_utf8((U8*)namepv, &namelen, &is_utf8);
if (is_utf8)
flags |= padadd_UTF8_NAME;
else
flags &= ~padadd_UTF8_NAME;
}
offset = pad_findlex(namepv, namelen, flags,
PL_compcv, PL_cop_seqmax, 1, NULL, &out_sv, &out_flags);
if ((PADOFFSET)offset != NOT_IN_PAD)
return offset;
/* look for an our that's being introduced; this allows
* our $foo = 0 unless defined $foo;
* to not give a warning. (Yes, this is a hack) */
nameav = PadlistARRAY(CvPADLIST(PL_compcv))[0];
name_svp = AvARRAY(nameav);
for (offset = AvFILLp(nameav); offset > 0; offset--) {
const SV * const namesv = name_svp[offset];
if (namesv && namesv != &PL_sv_undef
&& !SvFAKE(namesv)
&& (SvPAD_OUR(namesv))
&& SvCUR(namesv) == namelen
&& sv_eq_pvn_flags(aTHX_ namesv, namepv, namelen,
flags & padadd_UTF8_NAME ? SVf_UTF8 : 0 )
&& COP_SEQ_RANGE_LOW(namesv) == PERL_PADSEQ_INTRO
)
return offset;
}
return NOT_IN_PAD;
}
/*
=for apidoc Am|PADOFFSET|pad_findmy_pv|const char *name|U32 flags
Exactly like L</pad_findmy_pvn>, but takes a nul-terminated string
instead of a string/length pair.
=cut
*/
PADOFFSET
Perl_pad_findmy_pv(pTHX_ const char *name, U32 flags)
{
PERL_ARGS_ASSERT_PAD_FINDMY_PV;
return pad_findmy_pvn(name, strlen(name), flags);
}