forked from schacon/perl
/
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
This file contains the functions that create and manipulate scratchpads,
which are array-of-array data structures attached to a CV (ie a sub)
and which store lexical variables and opcode temporary and per-thread
values.
=for apidoc m|AV *|CvPADLIST|CV *cv
CV's can have CvPADLIST(cv) set to point to an AV.
For these purposes "forms" 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 CvPADLIST AV has does not have AvREAL set, so REFCNT of component items
is managed "manual" (mostly in pad.c) rather than normal av.c rules.
The items in the AV are not SVs as for a normal AV, but other AVs:
0'th Entry of the CvPADLIST is an AV which represents the "names" or rather
the "static type information" for lexicals.
The CvDEPTH'th entry of CvPADLIST AV is an AV which is the stack frame at that
depth of recursion into the CV.
The 0'th slot of a frame AV is an AV which is @_.
other entries are storage for variables and op targets.
During compilation:
C<PL_comppad_name> is set to the names AV.
C<PL_comppad> is set to the frame AV for the frame CvDEPTH == 1.
C<PL_curpad> is set to the body of the frame AV (i.e. AvARRAY(PL_comppad)).
During execution, C<PL_comppad> and C<PL_curpad> refer to the live
frame of the currently executing sub.
Iterating over the names AV 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 (SVs_PADMY/SVs_PADOUR) 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"" like
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 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 frame AV
is a CV representing a possible closure.
(SvFAKE 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'
=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
#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
/*
=for apidoc pad_new
Create a new compiling padlist, saving and updating the various global
vars at the same time as creating the pad itself. The following flags
can be OR'ed together:
padnew_CLONE this pad is for a cloned CV
padnew_SAVE save old globals
padnew_SAVESUB also save extra stuff for start of sub
=cut
*/
PADLIST *
Perl_pad_new(pTHX_ int flags)
{
dVAR;
AV *padlist, *padname, *pad;
SV **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();
SAVESPTR(PL_comppad_name);
if (! (flags & padnew_CLONE)) {
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 ... */
padlist = newAV();
padname = newAV();
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);
}
else {
av_store(pad, 0, NULL);
}
AvREAL_off(padlist);
/* 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, SV*);
AvFILLp(padlist) = 1;
AvMAX(padlist) = 1;
AvALLOC(padlist) = ary;
AvARRAY(padlist) = ary;
ary[0] = MUTABLE_SV(padname);
ary[1] = MUTABLE_SV(pad);
/* ... then update state variables */
PL_comppad_name = padname;
PL_comppad = pad;
PL_curpad = AvARRAY(pad);
if (! (flags & padnew_CLONE)) {
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);
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))
);
#ifdef USE_ITHREADS
if (CvFILE(cv) && !CvISXSUB(cv)) {
/* for XSUBs CvFILE point directly to static memory; __FILE__ */
Safefree(CvFILE(cv));
}
CvFILE(cv) = NULL;
#endif
if (!CvISXSUB(cv) && CvROOT(cv)) {
if (SvTYPE(cv) == SVt_PVCV && CvDEPTH(cv))
Perl_croak(aTHX_ "Can't undef active subroutine");
ENTER;
PAD_SAVE_SETNULLPAD();
op_free(CvROOT(cv));
CvROOT(cv) = NULL;
CvSTART(cv) = NULL;
LEAVE;
}
SvPOK_off(MUTABLE_SV(cv)); /* forget prototype */
CvGV_set(cv, NULL);
/* This statement and the subsequence if block was pad_undef(). */
pad_peg("pad_undef");
if (padlist && !SvIS_FREED(padlist) /* may be during global destruction */
) {
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);
AV * const comppad_name = MUTABLE_AV(AvARRAY(padlist)[0]);
SV ** const namepad = AvARRAY(comppad_name);
AV * const comppad = MUTABLE_AV(AvARRAY(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);
namepad[ix] = NULL;
SvREFCNT_dec(namesv);
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 = AvFILLp(padlist);
while (ix > 0) {
SV* const sv = AvARRAY(padlist)[ix--];
if (sv) {
if (sv == (const SV *)PL_comppad) {
PL_comppad = NULL;
PL_curpad = NULL;
}
SvREFCNT_dec(sv);
}
}
{
SV *const sv = AvARRAY(padlist)[0];
if (sv == (const SV *)PL_comppad_name)
PL_comppad_name = NULL;
SvREFCNT_dec(sv);
}
SvREFCNT_dec(MUTABLE_SV(CvPADLIST(cv)));
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 */
CvFLAGS(cv) &= (CVf_WEAKOUTSIDE|CVf_CVGV_RC);
}
static PADOFFSET
S_pad_add_name_sv(pTHX_ SV *namesv, const U32 flags, HV *typestash,
HV *ourstash)
{
dVAR;
const PADOFFSET offset = pad_alloc(OP_PADSV, SVs_PADMY);
PERL_ARGS_ASSERT_PAD_ADD_NAME_SV;
ASSERT_CURPAD_ACTIVE("pad_add_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 pad_add_name
Create a new name and associated PADMY SV in the current pad; return the
offset.
If C<typestash> is valid, the name is for a typed lexical; set the
name's stash to that value.
If C<ourstash> is valid, it's an our lexical, set the name's
SvOURSTASH to that value
If fake, it means we're cloning an existing entry
=cut
*/
PADOFFSET
Perl_pad_add_name(pTHX_ const char *name, const STRLEN len, const U32 flags,
HV *typestash, HV *ourstash)
{
dVAR;
PADOFFSET offset;
SV *namesv;
PERL_ARGS_ASSERT_PAD_ADD_NAME;
if (flags & ~(padadd_OUR|padadd_STATE|padadd_NO_DUP_CHECK))
Perl_croak(aTHX_ "panic: pad_add_name illegal flag bits 0x%" UVxf,
(UV)flags);
namesv = newSV_type((ourstash || typestash) ? SVt_PVMG : SVt_PVNV);
/* Until we're using the length for real, cross check that we're being told
the truth. */
PERL_UNUSED_ARG(len);
assert(strlen(name) == len);
sv_setpv(namesv, name);
if ((flags & padadd_NO_DUP_CHECK) == 0) {
/* check for duplicate declaration */
pad_check_dup(namesv, flags & padadd_OUR, ourstash);
}
offset = pad_add_name_sv(namesv, flags, 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 (*name == '@')
sv_upgrade(PL_curpad[offset], SVt_PVAV);
else if (*name == '%')
sv_upgrade(PL_curpad[offset], SVt_PVHV);
assert(SvPADMY(PL_curpad[offset]));
DEBUG_Xv(PerlIO_printf(Perl_debug_log,
"Pad addname: %ld \"%s\" new lex=0x%"UVxf"\n",
(long)offset, name, PTR2UV(PL_curpad[offset])));
return offset;
}
/*
=for apidoc pad_alloc
Allocate a new my or tmp pad entry. For a my, simply push a null SV onto
the end of PL_comppad, but for a tmp, scan the pad from PL_padix upwards
for a slot which has no name and no active value.
=cut
*/
/* XXX DAPM integrate alloc(), add_name() and add_anon(),
* or at least rationalise ??? */
/* And flag whether the incoming name is UTF8 or 8 bit?
Could do this either with the +ve/-ve hack of the HV code, or expanding
the flag bits. Either way, this makes proper Unicode safe pad support.
NWC
*/
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");
if (PL_pad_reset_pending)
pad_reset();
if (tmptype & SVs_PADMY) {
sv = *av_fetch(PL_comppad, AvFILLp(PL_comppad) + 1, TRUE);
retval = AvFILLp(PL_comppad);
}
else {
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 pad_add_anon
Add an anon code entry to the current compiling pad
=cut
*/
PADOFFSET
Perl_pad_add_anon(pTHX_ SV* sv, OPCODE op_type)
{
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(op_type, SVs_PADMY);
av_store(PL_comppad_name, ix, name);
/* XXX DAPM use PL_curpad[] ? */
av_store(PL_comppad, ix, sv);
SvPADMY_on(sv);
/* to avoid ref loops, we never have parent + child referencing each
* other simultaneously */
if (CvOUTSIDE((const CV *)sv)) {
assert(!CvWEAKOUTSIDE((const CV *)sv));
CvWEAKOUTSIDE_on(MUTABLE_CV(sv));
SvREFCNT_dec(CvOUTSIDE(MUTABLE_CV(sv)));
}
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, const 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" */
Perl_warner(aTHX_ packWARN(WARN_MISC),
"\"%s\" variable %"SVf" masks earlier declaration in same %s",
(is_our ? "our" : PL_parser->in_my == KEY_my ? "my" : "state"),
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 pad_findmy
Given a lexical name, try to find its offset, first in the current pad,
or failing that, in the pads of any lexically enclosing subs (including
the complications introduced by eval). If the name is found in an outer pad,
then a fake entry is added to the current pad.
Returns the offset in the current pad, or NOT_IN_PAD on failure.
=cut
*/
PADOFFSET
Perl_pad_findmy(pTHX_ const char *name, STRLEN len, U32 flags)
{
dVAR;
SV *out_sv;
int out_flags;
I32 offset;
const AV *nameav;
SV **name_svp;
PERL_ARGS_ASSERT_PAD_FINDMY;
pad_peg("pad_findmy");
if (flags)
Perl_croak(aTHX_ "panic: pad_findmy illegal flag bits 0x%" UVxf,
(UV)flags);
/* Yes, it is a bug (read work in progress) that we're not really using this
length parameter, and instead relying on strlen() later on. But I'm not
comfortable about changing the pad API piecemeal to use and rely on
lengths. This only exists to avoid an "unused parameter" warning. */
if (len < 2)
return NOT_IN_PAD;
/* But until we're using the length for real, cross check that we're being
told the truth. */
assert(strlen(name) == len);
offset = pad_findlex(name, 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 = MUTABLE_AV(AvARRAY(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))
&& strEQ(SvPVX_const(namesv), name)
&& COP_SEQ_RANGE_LOW(namesv) == PERL_PADSEQ_INTRO
)
return offset;
}
return NOT_IN_PAD;
}
/*
* Returns the offset of a lexical $_, if there is one, at run time.
* Used by the UNDERBAR XS macro.
*/
PADOFFSET
Perl_find_rundefsvoffset(pTHX)
{
dVAR;
SV *out_sv;
int out_flags;
return pad_findlex("$_", find_runcv(NULL), PL_curcop->cop_seq, 1,
NULL, &out_sv, &out_flags);
}
/*
* Returns a lexical $_, if there is one, at run time ; or the global one
* otherwise.
*/
SV *
Perl_find_rundefsv(pTHX)
{
SV *namesv;
int flags;
PADOFFSET po;
po = pad_findlex("$_", find_runcv(NULL), PL_curcop->cop_seq, 1,
NULL, &namesv, &flags);
if (po == NOT_IN_PAD || SvPAD_OUR(namesv))
return DEFSV;
return PAD_SVl(po);
}
/*
=for apidoc pad_findlex
Find a named lexical anywhere in a chain of nested pads. Add fake entries
in the inner pads if it's found in an outer one.
Returns the offset in the bottom pad of the lex or the fake lex.
cv is the CV in which to start the search, and seq is the current cop_seq
to match against. If warn is true, print appropriate warnings. The out_*
vars return values, and so are pointers to where the returned values
should be stored. out_capture, if non-null, requests that the innermost
instance of the lexical is captured; out_name_sv is set to the innermost
matched namesv or fake namesv; out_flags returns the flags normally
associated with the IVX field of a fake namesv.
Note that pad_findlex() is recursive; it recurses up the chain of CVs,
then comes back down, adding fake entries as it goes. It has to be this way
because fake namesvs in anon protoypes have to store in xlow the index into
the parent pad.
=cut
*/
/* the CV has finished being compiled. This is not a sufficient test for
* all CVs (eg XSUBs), but suffices for the CVs found in a lexical chain */
#define CvCOMPILED(cv) CvROOT(cv)
/* the CV does late binding of its lexicals */
#define CvLATE(cv) (CvANON(cv) || SvTYPE(cv) == SVt_PVFM)
STATIC PADOFFSET
S_pad_findlex(pTHX_ const char *name, const CV* cv, U32 seq, int warn,
SV** out_capture, SV** out_name_sv, int *out_flags)
{
dVAR;
I32 offset, new_offset;
SV *new_capture;
SV **new_capturep;
const AV * const padlist = CvPADLIST(cv);
PERL_ARGS_ASSERT_PAD_FINDLEX;
*out_flags = 0;
DEBUG_Xv(PerlIO_printf(Perl_debug_log,
"Pad findlex cv=0x%"UVxf" searching \"%s\" seq=%d%s\n",
PTR2UV(cv), name, (int)seq, out_capture ? " capturing" : "" ));
/* first, search this pad */
if (padlist) { /* not an undef CV */
I32 fake_offset = 0;
const AV * const nameav = MUTABLE_AV(AvARRAY(padlist)[0]);
SV * const * const name_svp = AvARRAY(nameav);
for (offset = AvFILLp(nameav); offset > 0; offset--) {
const SV * const namesv = name_svp[offset];
if (namesv && namesv != &PL_sv_undef
&& strEQ(SvPVX_const(namesv), name))
{
if (SvFAKE(namesv)) {
fake_offset = offset; /* in case we don't find a real one */
continue;
}
/* is seq within the range _LOW to _HIGH ?
* This is complicated by the fact that PL_cop_seqmax
* may have wrapped around at some point */
if (COP_SEQ_RANGE_LOW(namesv) == PERL_PADSEQ_INTRO)
continue; /* not yet introduced */
if (COP_SEQ_RANGE_HIGH(namesv) == PERL_PADSEQ_INTRO) {
/* in compiling scope */
if (
(seq > COP_SEQ_RANGE_LOW(namesv))
? (seq - COP_SEQ_RANGE_LOW(namesv) < (U32_MAX >> 1))
: (COP_SEQ_RANGE_LOW(namesv) - seq > (U32_MAX >> 1))
)
break;
}
else if (
(COP_SEQ_RANGE_LOW(namesv) > COP_SEQ_RANGE_HIGH(namesv))
?
( seq > COP_SEQ_RANGE_LOW(namesv)
|| seq <= COP_SEQ_RANGE_HIGH(namesv))
: ( seq > COP_SEQ_RANGE_LOW(namesv)
&& seq <= COP_SEQ_RANGE_HIGH(namesv))
)
break;
}
}
if (offset > 0 || fake_offset > 0 ) { /* a match! */
if (offset > 0) { /* not fake */
fake_offset = 0;
*out_name_sv = name_svp[offset]; /* return the namesv */
/* set PAD_FAKELEX_MULTI if this lex can have multiple
* instances. For now, we just test !CvUNIQUE(cv), but
* ideally, we should detect my's declared within loops
* etc - this would allow a wider range of 'not stayed
* shared' warnings. We also treated already-compiled
* lexes as not multi as viewed from evals. */
*out_flags = CvANON(cv) ?
PAD_FAKELEX_ANON :
(!CvUNIQUE(cv) && ! CvCOMPILED(cv))
? PAD_FAKELEX_MULTI : 0;
DEBUG_Xv(PerlIO_printf(Perl_debug_log,
"Pad findlex cv=0x%"UVxf" matched: offset=%ld (%lu,%lu)\n",
PTR2UV(cv), (long)offset,
(unsigned long)COP_SEQ_RANGE_LOW(*out_name_sv),
(unsigned long)COP_SEQ_RANGE_HIGH(*out_name_sv)));
}
else { /* fake match */
offset = fake_offset;
*out_name_sv = name_svp[offset]; /* return the namesv */
*out_flags = PARENT_FAKELEX_FLAGS(*out_name_sv);
DEBUG_Xv(PerlIO_printf(Perl_debug_log,
"Pad findlex cv=0x%"UVxf" matched: offset=%ld flags=0x%lx index=%lu\n",
PTR2UV(cv), (long)offset, (unsigned long)*out_flags,
(unsigned long) PARENT_PAD_INDEX(*out_name_sv)
));
}
/* return the lex? */
if (out_capture) {
/* our ? */
if (SvPAD_OUR(*out_name_sv)) {
*out_capture = NULL;
return offset;
}
/* trying to capture from an anon prototype? */
if (CvCOMPILED(cv)
? CvANON(cv) && CvCLONE(cv) && !CvCLONED(cv)
: *out_flags & PAD_FAKELEX_ANON)
{
if (warn)
Perl_ck_warner(aTHX_ packWARN(WARN_CLOSURE),
"Variable \"%s\" is not available", name);
*out_capture = NULL;
}
/* real value */
else {
int newwarn = warn;
if (!CvCOMPILED(cv) && (*out_flags & PAD_FAKELEX_MULTI)
&& !SvPAD_STATE(name_svp[offset])
&& warn && ckWARN(WARN_CLOSURE)) {
newwarn = 0;
Perl_warner(aTHX_ packWARN(WARN_CLOSURE),
"Variable \"%s\" will not stay shared", name);
}
if (fake_offset && CvANON(cv)
&& CvCLONE(cv) &&!CvCLONED(cv))
{
SV *n;
/* not yet caught - look further up */
DEBUG_Xv(PerlIO_printf(Perl_debug_log,
"Pad findlex cv=0x%"UVxf" chasing lex in outer pad\n",
PTR2UV(cv)));
n = *out_name_sv;
(void) pad_findlex(name, CvOUTSIDE(cv),
CvOUTSIDE_SEQ(cv),
newwarn, out_capture, out_name_sv, out_flags);
*out_name_sv = n;
return offset;
}
*out_capture = AvARRAY(MUTABLE_AV(AvARRAY(padlist)[
CvDEPTH(cv) ? CvDEPTH(cv) : 1]))[offset];
DEBUG_Xv(PerlIO_printf(Perl_debug_log,
"Pad findlex cv=0x%"UVxf" found lex=0x%"UVxf"\n",
PTR2UV(cv), PTR2UV(*out_capture)));
if (SvPADSTALE(*out_capture)
&& !SvPAD_STATE(name_svp[offset]))
{
Perl_ck_warner(aTHX_ packWARN(WARN_CLOSURE),
"Variable \"%s\" is not available", name);
*out_capture = NULL;
}
}
if (!*out_capture) {
if (*name == '@')
*out_capture = sv_2mortal(MUTABLE_SV(newAV()));
else if (*name == '%')
*out_capture = sv_2mortal(MUTABLE_SV(newHV()));
else
*out_capture = sv_newmortal();
}