xref: /openbsd-src/gnu/usr.bin/perl/pad.c (revision fc405d53b73a2d73393cb97f684863d17b583e38)
1 /*    pad.c
2  *
3  *    Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008
4  *    by Larry Wall and others
5  *
6  *    You may distribute under the terms of either the GNU General Public
7  *    License or the Artistic License, as specified in the README file.
8  */
9 
10 /*
11  *  'Anyway: there was this Mr. Frodo left an orphan and stranded, as you
12  *   might say, among those queer Bucklanders, being brought up anyhow in
13  *   Brandy Hall.  A regular warren, by all accounts.  Old Master Gorbadoc
14  *   never had fewer than a couple of hundred relations in the place.
15  *   Mr. Bilbo never did a kinder deed than when he brought the lad back
16  *   to live among decent folk.'                           --the Gaffer
17  *
18  *     [p.23 of _The Lord of the Rings_, I/i: "A Long-Expected Party"]
19  */
20 
21 /*
22 =for apidoc_section $pad
23 
24 =for apidoc Amx|PADLIST *|CvPADLIST|CV *cv
25 
26 CV's can have CvPADLIST(cv) set to point to a PADLIST.  This is the CV's
27 scratchpad, which stores lexical variables and opcode temporary and
28 per-thread values.
29 
30 For these purposes "formats" are a kind-of CV; eval""s are too (except they're
31 not callable at will and are always thrown away after the eval"" is done
32 executing).  Require'd files are simply evals without any outer lexical
33 scope.
34 
35 XSUBs do not have a C<CvPADLIST>.  C<dXSTARG> fetches values from C<PL_curpad>,
36 but that is really the callers pad (a slot of which is allocated by
37 every entersub). Do not get or set C<CvPADLIST> if a CV is an XSUB (as
38 determined by C<CvISXSUB()>), C<CvPADLIST> slot is reused for a different
39 internal purpose in XSUBs.
40 
41 The PADLIST has a C array where pads are stored.
42 
43 The 0th entry of the PADLIST is a PADNAMELIST
44 which represents the "names" or rather
45 the "static type information" for lexicals.  The individual elements of a
46 PADNAMELIST are PADNAMEs.  Future
47 refactorings might stop the PADNAMELIST from being stored in the PADLIST's
48 array, so don't rely on it.  See L</PadlistNAMES>.
49 
50 The CvDEPTH'th entry of a PADLIST is a PAD (an AV) which is the stack frame
51 at that depth of recursion into the CV.  The 0th slot of a frame AV is an
52 AV which is C<@_>.  Other entries are storage for variables and op targets.
53 
54 Iterating over the PADNAMELIST iterates over all possible pad
55 items.  Pad slots for targets (C<SVs_PADTMP>)
56 and GVs end up having &PL_padname_undef "names", while slots for constants
57 have C<&PL_padname_const> "names" (see C<L</pad_alloc>>).  That
58 C<&PL_padname_undef>
59 and C<&PL_padname_const> are used is an implementation detail subject to
60 change.  To test for them, use C<!PadnamePV(name)> and
61 S<C<PadnamePV(name) && !PadnameLEN(name)>>, respectively.
62 
63 Only C<my>/C<our> variable slots get valid names.
64 The rest are op targets/GVs/constants which are statically allocated
65 or resolved at compile time.  These don't have names by which they
66 can be looked up from Perl code at run time through eval"" the way
67 C<my>/C<our> variables can be.  Since they can't be looked up by "name"
68 but only by their index allocated at compile time (which is usually
69 in C<< PL_op->op_targ >>), wasting a name SV for them doesn't make sense.
70 
71 The pad names in the PADNAMELIST have their PV holding the name of
72 the variable.  The C<COP_SEQ_RANGE_LOW> and C<_HIGH> fields form a range
73 (low+1..high inclusive) of cop_seq numbers for which the name is
74 valid.  During compilation, these fields may hold the special value
75 PERL_PADSEQ_INTRO to indicate various stages:
76 
77  COP_SEQ_RANGE_LOW        _HIGH
78  -----------------        -----
79  PERL_PADSEQ_INTRO            0   variable not yet introduced:
80                                   { my ($x
81  valid-seq#   PERL_PADSEQ_INTRO   variable in scope:
82                                   { my ($x);
83  valid-seq#          valid-seq#   compilation of scope complete:
84                                   { my ($x); .... }
85 
86 When a lexical var hasn't yet been introduced, it already exists from the
87 perspective of duplicate declarations, but not for variable lookups, e.g.
88 
89     my ($x, $x); # '"my" variable $x masks earlier declaration'
90     my $x = $x;  # equal to my $x = $::x;
91 
92 For typed lexicals C<PadnameTYPE> points at the type stash.  For C<our>
93 lexicals, C<PadnameOURSTASH> points at the stash of the associated global (so
94 that duplicate C<our> declarations in the same package can be detected).
95 C<PadnameGEN> is sometimes used to store the generation number during
96 compilation.
97 
98 If C<PadnameOUTER> is set on the pad name, then that slot in the frame AV
99 is a REFCNT'ed reference to a lexical from "outside".  Such entries
100 are sometimes referred to as 'fake'.  In this case, the name does not
101 use 'low' and 'high' to store a cop_seq range, since it is in scope
102 throughout.  Instead 'high' stores some flags containing info about
103 the real lexical (is it declared in an anon, and is it capable of being
104 instantiated multiple times?), and for fake ANONs, 'low' contains the index
105 within the parent's pad where the lexical's value is stored, to make
106 cloning quicker.
107 
108 If the 'name' is C<&> the corresponding entry in the PAD
109 is a CV representing a possible closure.
110 
111 Note that formats are treated as anon subs, and are cloned each time
112 write is called (if necessary).
113 
114 The flag C<SVs_PADSTALE> is cleared on lexicals each time the C<my()> is executed,
115 and set on scope exit.  This allows the
116 C<"Variable $x is not available"> warning
117 to be generated in evals, such as
118 
119     { my $x = 1; sub f { eval '$x'} } f();
120 
121 For state vars, C<SVs_PADSTALE> is overloaded to mean 'not yet initialised',
122 but this internal state is stored in a separate pad entry.
123 
124 =for apidoc Amnh||SVs_PADSTALE
125 
126 =for apidoc AmnxU|PADNAMELIST *|PL_comppad_name
127 
128 During compilation, this points to the array containing the names part
129 of the pad for the currently-compiling code.
130 
131 =for apidoc AmnxU|PAD *|PL_comppad
132 
133 During compilation, this points to the array containing the values
134 part of the pad for the currently-compiling code.  (At runtime a CV may
135 have many such value arrays; at compile time just one is constructed.)
136 At runtime, this points to the array containing the currently-relevant
137 values for the pad for the currently-executing code.
138 
139 =for apidoc AmnxU|SV **|PL_curpad
140 
141 Points directly to the body of the L</PL_comppad> array.
142 (I.e., this is C<PadARRAY(PL_comppad)>.)
143 
144 =cut
145 */
146 
147 
148 #include "EXTERN.h"
149 #define PERL_IN_PAD_C
150 #include "perl.h"
151 #include "keywords.h"
152 
153 #define COP_SEQ_RANGE_LOW_set(sv,val)		\
154   STMT_START { (sv)->xpadn_low = (val); } STMT_END
155 #define COP_SEQ_RANGE_HIGH_set(sv,val)		\
156   STMT_START { (sv)->xpadn_high = (val); } STMT_END
157 
158 #define PARENT_PAD_INDEX_set		COP_SEQ_RANGE_LOW_set
159 #define PARENT_FAKELEX_FLAGS_set	COP_SEQ_RANGE_HIGH_set
160 
161 #ifdef DEBUGGING
162 void
163 Perl_set_padlist(CV * cv, PADLIST *padlist){
164     PERL_ARGS_ASSERT_SET_PADLIST;
165 #  if PTRSIZE == 8
166     assert((Size_t)padlist != UINT64_C(0xEFEFEFEFEFEFEFEF));
167 #  elif PTRSIZE == 4
168     assert((Size_t)padlist != 0xEFEFEFEF);
169 #  else
170 #    error unknown pointer size
171 #  endif
172     assert(!CvISXSUB(cv));
173     ((XPVCV*)MUTABLE_PTR(SvANY(cv)))->xcv_padlist_u.xcv_padlist = padlist;
174 }
175 #endif
176 
177 /*
178 =for apidoc pad_new
179 
180 Create a new padlist, updating the global variables for the
181 currently-compiling padlist to point to the new padlist.  The following
182 flags can be OR'ed together:
183 
184     padnew_CLONE	this pad is for a cloned CV
185     padnew_SAVE		save old globals on the save stack
186     padnew_SAVESUB	also save extra stuff for start of sub
187 
188 =cut
189 */
190 
191 PADLIST *
192 Perl_pad_new(pTHX_ int flags)
193 {
194     PADLIST *padlist;
195     PADNAMELIST *padname;
196     PAD *pad;
197     PAD **ary;
198 
199     ASSERT_CURPAD_LEGAL("pad_new");
200 
201     /* save existing state, ... */
202 
203     if (flags & padnew_SAVE) {
204         SAVECOMPPAD();
205         if (! (flags & padnew_CLONE)) {
206             SAVESPTR(PL_comppad_name);
207             SAVESTRLEN(PL_padix);
208             SAVESTRLEN(PL_constpadix);
209             SAVESTRLEN(PL_comppad_name_fill);
210             SAVESTRLEN(PL_min_intro_pending);
211             SAVESTRLEN(PL_max_intro_pending);
212             SAVEBOOL(PL_cv_has_eval);
213             if (flags & padnew_SAVESUB) {
214                 SAVEBOOL(PL_pad_reset_pending);
215             }
216         }
217     }
218 
219     /* ... create new pad ... */
220 
221     Newxz(padlist, 1, PADLIST);
222     pad		= newAV();
223     Newxz(AvALLOC(pad), 4, SV *); /* Originally sized to
224                                      match av_extend default */
225     AvARRAY(pad) = AvALLOC(pad);
226     AvMAX(pad) = 3;
227     AvFILLp(pad) = 0; /* @_ or NULL, set below. */
228 
229     if (flags & padnew_CLONE) {
230         AV * const a0 = newAV();			/* will be @_ */
231         AvARRAY(pad)[0] = MUTABLE_SV(a0);
232         AvREIFY_only(a0);
233 
234         PadnamelistREFCNT(padname = PL_comppad_name)++;
235     }
236     else {
237         padlist->xpadl_id = PL_padlist_generation++;
238         /* Set implicitly through use of Newxz above
239             AvARRAY(pad)[0] = NULL;
240         */
241         padname = newPADNAMELIST(0);
242         padnamelist_store(padname, 0, &PL_padname_undef);
243     }
244 
245     /* Most subroutines never recurse, hence only need 2 entries in the padlist
246        array - names, and depth=1.  The default for av_store() is to allocate
247        0..3, and even an explicit call to av_extend() with <3 will be rounded
248        up, so we inline the allocation of the array here.  */
249     Newx(ary, 2, PAD *);
250     PadlistMAX(padlist) = 1;
251     PadlistARRAY(padlist) = ary;
252     ary[0] = (PAD *)padname;
253     ary[1] = pad;
254 
255     /* ... then update state variables */
256 
257     PL_comppad		= pad;
258     PL_curpad		= AvARRAY(pad);
259 
260     if (! (flags & padnew_CLONE)) {
261         PL_comppad_name	     = padname;
262         PL_comppad_name_fill = 0;
263         PL_min_intro_pending = 0;
264         PL_padix	     = 0;
265         PL_constpadix	     = 0;
266         PL_cv_has_eval	     = 0;
267     }
268 
269     DEBUG_X(PerlIO_printf(Perl_debug_log,
270           "Pad 0x%" UVxf "[0x%" UVxf "] new:       compcv=0x%" UVxf
271               " name=0x%" UVxf " flags=0x%" UVxf "\n",
272           PTR2UV(PL_comppad), PTR2UV(PL_curpad), PTR2UV(PL_compcv),
273               PTR2UV(padname), (UV)flags
274         )
275     );
276 
277     return (PADLIST*)padlist;
278 }
279 
280 
281 /*
282 =for apidoc_section $embedding
283 
284 =for apidoc cv_undef
285 
286 Clear out all the active components of a CV.  This can happen either
287 by an explicit C<undef &foo>, or by the reference count going to zero.
288 In the former case, we keep the C<CvOUTSIDE> pointer, so that any anonymous
289 children can still follow the full lexical scope chain.
290 
291 =cut
292 */
293 
294 void
295 Perl_cv_undef(pTHX_ CV *cv)
296 {
297     PERL_ARGS_ASSERT_CV_UNDEF;
298     cv_undef_flags(cv, 0);
299 }
300 
301 void
302 Perl_cv_undef_flags(pTHX_ CV *cv, U32 flags)
303 {
304     CV cvbody;/*CV body will never be realloced inside this func,
305                so dont read it more than once, use fake CV so existing macros
306                will work, the indirection and CV head struct optimized away*/
307     SvANY(&cvbody) = SvANY(cv);
308 
309     PERL_ARGS_ASSERT_CV_UNDEF_FLAGS;
310 
311     DEBUG_X(PerlIO_printf(Perl_debug_log,
312           "CV undef: cv=0x%" UVxf " comppad=0x%" UVxf "\n",
313             PTR2UV(cv), PTR2UV(PL_comppad))
314     );
315 
316     if (CvFILE(&cvbody)) {
317         char * file = CvFILE(&cvbody);
318         CvFILE(&cvbody) = NULL;
319         if(CvDYNFILE(&cvbody))
320             Safefree(file);
321     }
322 
323     /* CvSLABBED_off(&cvbody); *//* turned off below */
324     /* release the sub's body */
325     if (!CvISXSUB(&cvbody)) {
326         if(CvROOT(&cvbody)) {
327             assert(SvTYPE(cv) == SVt_PVCV || SvTYPE(cv) == SVt_PVFM); /*unsafe is safe */
328             if (CvDEPTHunsafe(&cvbody)) {
329                 assert(SvTYPE(cv) == SVt_PVCV);
330                 Perl_croak_nocontext("Can't undef active subroutine");
331             }
332             ENTER;
333 
334             PAD_SAVE_SETNULLPAD();
335 
336             if (CvSLABBED(&cvbody)) OpslabREFCNT_dec_padok(OpSLAB(CvROOT(&cvbody)));
337             op_free(CvROOT(&cvbody));
338             CvROOT(&cvbody) = NULL;
339             CvSTART(&cvbody) = NULL;
340             LEAVE;
341         }
342         else if (CvSLABBED(&cvbody)) {
343             if( CvSTART(&cvbody)) {
344                 ENTER;
345                 PAD_SAVE_SETNULLPAD();
346 
347                 /* discard any leaked ops */
348                 if (PL_parser)
349                     parser_free_nexttoke_ops(PL_parser, (OPSLAB *)CvSTART(&cvbody));
350                 opslab_force_free((OPSLAB *)CvSTART(&cvbody));
351                 CvSTART(&cvbody) = NULL;
352 
353                 LEAVE;
354             }
355 #ifdef DEBUGGING
356             else Perl_warn(aTHX_ "Slab leaked from cv %p", (void*)cv);
357 #endif
358         }
359     }
360     else { /* dont bother checking if CvXSUB(cv) is true, less branching */
361         CvXSUB(&cvbody) = NULL;
362     }
363     SvPOK_off(MUTABLE_SV(cv));		/* forget prototype */
364     sv_unmagic((SV *)cv, PERL_MAGIC_checkcall);
365     if (!(flags & CV_UNDEF_KEEP_NAME)) {
366         if (CvNAMED(&cvbody)) {
367             CvNAME_HEK_set(&cvbody, NULL);
368             CvNAMED_off(&cvbody);
369         }
370         else CvGV_set(cv, NULL);
371     }
372 
373     /* This statement and the subsequence if block was pad_undef().  */
374     pad_peg("pad_undef");
375 
376     if (!CvISXSUB(&cvbody) && CvPADLIST(&cvbody)) {
377         PADOFFSET ix;
378         const PADLIST *padlist = CvPADLIST(&cvbody);
379 
380         /* Free the padlist associated with a CV.
381            If parts of it happen to be current, we null the relevant PL_*pad*
382            global vars so that we don't have any dangling references left.
383            We also repoint the CvOUTSIDE of any about-to-be-orphaned inner
384            subs to the outer of this cv.  */
385 
386         DEBUG_X(PerlIO_printf(Perl_debug_log,
387                               "Pad undef: cv=0x%" UVxf " padlist=0x%" UVxf " comppad=0x%" UVxf "\n",
388                               PTR2UV(cv), PTR2UV(padlist), PTR2UV(PL_comppad))
389                 );
390 
391         /* detach any '&' anon children in the pad; if afterwards they
392          * are still live, fix up their CvOUTSIDEs to point to our outside,
393          * bypassing us. */
394 
395         if (PL_phase != PERL_PHASE_DESTRUCT) { /* don't bother during global destruction */
396             CV * const outercv = CvOUTSIDE(&cvbody);
397             const U32 seq = CvOUTSIDE_SEQ(&cvbody);
398             PADNAMELIST * const comppad_name = PadlistNAMES(padlist);
399             PADNAME ** const namepad = PadnamelistARRAY(comppad_name);
400             PAD * const comppad = PadlistARRAY(padlist)[1];
401             SV ** const curpad = AvARRAY(comppad);
402             for (ix = PadnamelistMAX(comppad_name); ix > 0; ix--) {
403                 PADNAME * const name = namepad[ix];
404                 if (name && PadnamePV(name) && *PadnamePV(name) == '&')
405                     {
406                         CV * const innercv = MUTABLE_CV(curpad[ix]);
407                         U32 inner_rc;
408                         assert(innercv);
409                         assert(SvTYPE(innercv) != SVt_PVFM);
410                         inner_rc = SvREFCNT(innercv);
411                         assert(inner_rc);
412 
413                         if (SvREFCNT(comppad) < 2) { /* allow for /(?{ sub{} })/  */
414                             curpad[ix] = NULL;
415                             SvREFCNT_dec_NN(innercv);
416                             inner_rc--;
417                         }
418 
419                         /* in use, not just a prototype */
420                         if (inner_rc && SvTYPE(innercv) == SVt_PVCV
421                          && (CvOUTSIDE(innercv) == cv))
422                         {
423                             assert(CvWEAKOUTSIDE(innercv));
424                             /* don't relink to grandfather if he's being freed */
425                             if (outercv && SvREFCNT(outercv)) {
426                                 CvWEAKOUTSIDE_off(innercv);
427                                 CvOUTSIDE(innercv) = outercv;
428                                 CvOUTSIDE_SEQ(innercv) = seq;
429                                 SvREFCNT_inc_simple_void_NN(outercv);
430                             }
431                             else {
432                                 CvOUTSIDE(innercv) = NULL;
433                             }
434                         }
435                     }
436             }
437         }
438 
439         ix = PadlistMAX(padlist);
440         while (ix > 0) {
441             PAD * const sv = PadlistARRAY(padlist)[ix--];
442             if (sv) {
443                 if (sv == PL_comppad) {
444                     PL_comppad = NULL;
445                     PL_curpad = NULL;
446                 }
447                 SvREFCNT_dec_NN(sv);
448             }
449         }
450         {
451             PADNAMELIST * const names = PadlistNAMES(padlist);
452             if (names == PL_comppad_name && PadnamelistREFCNT(names) == 1)
453                 PL_comppad_name = NULL;
454             PadnamelistREFCNT_dec(names);
455         }
456         if (PadlistARRAY(padlist)) Safefree(PadlistARRAY(padlist));
457         Safefree(padlist);
458         CvPADLIST_set(&cvbody, NULL);
459     }
460     else if (CvISXSUB(&cvbody))
461         CvHSCXT(&cvbody) = NULL;
462     /* else is (!CvISXSUB(&cvbody) && !CvPADLIST(&cvbody)) {do nothing;} */
463 
464 
465     /* remove CvOUTSIDE unless this is an undef rather than a free */
466     if (!SvREFCNT(cv)) {
467         CV * outside = CvOUTSIDE(&cvbody);
468         if(outside) {
469             CvOUTSIDE(&cvbody) = NULL;
470             if (!CvWEAKOUTSIDE(&cvbody))
471                 SvREFCNT_dec_NN(outside);
472         }
473     }
474     if (CvCONST(&cvbody)) {
475         SvREFCNT_dec(MUTABLE_SV(CvXSUBANY(&cvbody).any_ptr));
476         /* CvCONST_off(cv); *//* turned off below */
477     }
478     /* delete all flags except WEAKOUTSIDE and CVGV_RC, which indicate the
479      * ref status of CvOUTSIDE and CvGV, and ANON, NAMED and
480      * LEXICAL, which are used to determine the sub's name.  */
481     CvFLAGS(&cvbody) &= (CVf_WEAKOUTSIDE|CVf_CVGV_RC|CVf_ANON|CVf_LEXICAL
482                    |CVf_NAMED);
483 }
484 
485 /*
486 =for apidoc cv_forget_slab
487 
488 When a CV has a reference count on its slab (C<CvSLABBED>), it is responsible
489 for making sure it is freed.  (Hence, no two CVs should ever have a
490 reference count on the same slab.)  The CV only needs to reference the slab
491 during compilation.  Once it is compiled and C<CvROOT> attached, it has
492 finished its job, so it can forget the slab.
493 
494 =cut
495 */
496 
497 void
498 Perl_cv_forget_slab(pTHX_ CV *cv)
499 {
500     bool slabbed;
501     OPSLAB *slab = NULL;
502 
503     if (!cv)
504         return;
505     slabbed = cBOOL(CvSLABBED(cv));
506     if (!slabbed) return;
507 
508     CvSLABBED_off(cv);
509 
510     if      (CvROOT(cv))  slab = OpSLAB(CvROOT(cv));
511     else if (CvSTART(cv)) slab = (OPSLAB *)CvSTART(cv);
512 #ifdef DEBUGGING
513     else if (slabbed)     Perl_warn(aTHX_ "Slab leaked from cv %p", (void*)cv);
514 #endif
515 
516     if (slab) {
517 #ifdef PERL_DEBUG_READONLY_OPS
518         const size_t refcnt = slab->opslab_refcnt;
519 #endif
520         OpslabREFCNT_dec(slab);
521 #ifdef PERL_DEBUG_READONLY_OPS
522         if (refcnt > 1) Slab_to_ro(slab);
523 #endif
524     }
525 }
526 
527 /*
528 =for apidoc pad_alloc_name
529 
530 Allocates a place in the currently-compiling
531 pad (via L<perlapi/pad_alloc>) and
532 then stores a name for that entry.  C<name> is adopted and
533 becomes the name entry; it must already contain the name
534 string.  C<typestash> and C<ourstash> and the C<padadd_STATE>
535 flag get added to C<name>.  None of the other
536 processing of L<perlapi/pad_add_name_pvn>
537 is done.  Returns the offset of the allocated pad slot.
538 
539 =cut
540 */
541 
542 static PADOFFSET
543 S_pad_alloc_name(pTHX_ PADNAME *name, U32 flags, HV *typestash,
544                        HV *ourstash)
545 {
546     const PADOFFSET offset = pad_alloc(OP_PADSV, SVs_PADMY);
547 
548     PERL_ARGS_ASSERT_PAD_ALLOC_NAME;
549 
550     ASSERT_CURPAD_ACTIVE("pad_alloc_name");
551 
552     if (typestash) {
553         SvPAD_TYPED_on(name);
554         PadnameTYPE(name) =
555             MUTABLE_HV(SvREFCNT_inc_simple_NN(MUTABLE_SV(typestash)));
556     }
557     if (ourstash) {
558         SvPAD_OUR_on(name);
559         SvOURSTASH_set(name, ourstash);
560         SvREFCNT_inc_simple_void_NN(ourstash);
561     }
562     else if (flags & padadd_STATE) {
563         SvPAD_STATE_on(name);
564     }
565 
566     padnamelist_store(PL_comppad_name, offset, name);
567     if (PadnameLEN(name) > 1)
568         PadnamelistMAXNAMED(PL_comppad_name) = offset;
569     return offset;
570 }
571 
572 /*
573 =for apidoc pad_add_name_pvn
574 
575 Allocates a place in the currently-compiling pad for a named lexical
576 variable.  Stores the name and other metadata in the name part of the
577 pad, and makes preparations to manage the variable's lexical scoping.
578 Returns the offset of the allocated pad slot.
579 
580 C<namepv>/C<namelen> specify the variable's name, including leading sigil.
581 If C<typestash> is non-null, the name is for a typed lexical, and this
582 identifies the type.  If C<ourstash> is non-null, it's a lexical reference
583 to a package variable, and this identifies the package.  The following
584 flags can be OR'ed together:
585 
586  padadd_OUR          redundantly specifies if it's a package var
587  padadd_STATE        variable will retain value persistently
588  padadd_NO_DUP_CHECK skip check for lexical shadowing
589 
590 =cut
591 */
592 
593 PADOFFSET
594 Perl_pad_add_name_pvn(pTHX_ const char *namepv, STRLEN namelen,
595                 U32 flags, HV *typestash, HV *ourstash)
596 {
597     PADOFFSET offset;
598     PADNAME *name;
599 
600     PERL_ARGS_ASSERT_PAD_ADD_NAME_PVN;
601 
602     if (flags & ~(padadd_OUR|padadd_STATE|padadd_NO_DUP_CHECK))
603         Perl_croak(aTHX_ "panic: pad_add_name_pvn illegal flag bits 0x%" UVxf,
604                    (UV)flags);
605 
606     name = newPADNAMEpvn(namepv, namelen);
607 
608     if ((flags & padadd_NO_DUP_CHECK) == 0) {
609         ENTER;
610         SAVEFREEPADNAME(name); /* in case of fatal warnings */
611         /* check for duplicate declaration */
612         pad_check_dup(name, flags & padadd_OUR, ourstash);
613         PadnameREFCNT(name)++;
614         LEAVE;
615     }
616 
617     offset = pad_alloc_name(name, flags, typestash, ourstash);
618 
619     /* not yet introduced */
620     COP_SEQ_RANGE_LOW_set(name, PERL_PADSEQ_INTRO);
621     COP_SEQ_RANGE_HIGH_set(name, 0);
622 
623     if (!PL_min_intro_pending)
624         PL_min_intro_pending = offset;
625     PL_max_intro_pending = offset;
626     /* if it's not a simple scalar, replace with an AV or HV */
627     assert(SvTYPE(PL_curpad[offset]) == SVt_NULL);
628     assert(SvREFCNT(PL_curpad[offset]) == 1);
629     if (namelen != 0 && *namepv == '@')
630         sv_upgrade(PL_curpad[offset], SVt_PVAV);
631     else if (namelen != 0 && *namepv == '%')
632         sv_upgrade(PL_curpad[offset], SVt_PVHV);
633     else if (namelen != 0 && *namepv == '&')
634         sv_upgrade(PL_curpad[offset], SVt_PVCV);
635     assert(SvPADMY(PL_curpad[offset]));
636     DEBUG_Xv(PerlIO_printf(Perl_debug_log,
637                            "Pad addname: %ld \"%s\" new lex=0x%" UVxf "\n",
638                            (long)offset, PadnamePV(name),
639                            PTR2UV(PL_curpad[offset])));
640 
641     return offset;
642 }
643 
644 /*
645 =for apidoc pad_add_name_pv
646 
647 Exactly like L</pad_add_name_pvn>, but takes a nul-terminated string
648 instead of a string/length pair.
649 
650 =cut
651 */
652 
653 PADOFFSET
654 Perl_pad_add_name_pv(pTHX_ const char *name,
655                      const U32 flags, HV *typestash, HV *ourstash)
656 {
657     PERL_ARGS_ASSERT_PAD_ADD_NAME_PV;
658     return pad_add_name_pvn(name, strlen(name), flags, typestash, ourstash);
659 }
660 
661 /*
662 =for apidoc pad_add_name_sv
663 
664 Exactly like L</pad_add_name_pvn>, but takes the name string in the form
665 of an SV instead of a string/length pair.
666 
667 =cut
668 */
669 
670 PADOFFSET
671 Perl_pad_add_name_sv(pTHX_ SV *name, U32 flags, HV *typestash, HV *ourstash)
672 {
673     char *namepv;
674     STRLEN namelen;
675     PERL_ARGS_ASSERT_PAD_ADD_NAME_SV;
676     namepv = SvPVutf8(name, namelen);
677     return pad_add_name_pvn(namepv, namelen, flags, typestash, ourstash);
678 }
679 
680 /*
681 =for apidoc pad_alloc
682 
683 Allocates a place in the currently-compiling pad,
684 returning the offset of the allocated pad slot.
685 No name is initially attached to the pad slot.
686 C<tmptype> is a set of flags indicating the kind of pad entry required,
687 which will be set in the value SV for the allocated pad entry:
688 
689     SVs_PADMY    named lexical variable ("my", "our", "state")
690     SVs_PADTMP   unnamed temporary store
691     SVf_READONLY constant shared between recursion levels
692 
693 C<SVf_READONLY> has been supported here only since perl 5.20.  To work with
694 earlier versions as well, use C<SVf_READONLY|SVs_PADTMP>.  C<SVf_READONLY>
695 does not cause the SV in the pad slot to be marked read-only, but simply
696 tells C<pad_alloc> that it I<will> be made read-only (by the caller), or at
697 least should be treated as such.
698 
699 C<optype> should be an opcode indicating the type of operation that the
700 pad entry is to support.  This doesn't affect operational semantics,
701 but is used for debugging.
702 
703 =cut
704 */
705 
706 PADOFFSET
707 Perl_pad_alloc(pTHX_ I32 optype, U32 tmptype)
708 {
709     SV *sv;
710     PADOFFSET retval;
711 
712     PERL_UNUSED_ARG(optype);
713     ASSERT_CURPAD_ACTIVE("pad_alloc");
714 
715     if (AvARRAY(PL_comppad) != PL_curpad)
716         Perl_croak(aTHX_ "panic: pad_alloc, %p!=%p",
717                    AvARRAY(PL_comppad), PL_curpad);
718     if (PL_pad_reset_pending)
719         pad_reset();
720     if (tmptype == SVs_PADMY) { /* Not & because this ‘flag’ is 0.  */
721         /* For a my, simply push a null SV onto the end of PL_comppad. */
722         sv = *av_store_simple(PL_comppad, AvFILLp(PL_comppad) + 1, newSV_type(SVt_NULL));
723         retval = (PADOFFSET)AvFILLp(PL_comppad);
724     }
725     else {
726         /* For a tmp, scan the pad from PL_padix upwards
727          * for a slot which has no name and no active value.
728          * For a constant, likewise, but use PL_constpadix.
729          */
730         PADNAME * const * const names = PadnamelistARRAY(PL_comppad_name);
731         const SSize_t names_fill = PadnamelistMAX(PL_comppad_name);
732         const bool konst = cBOOL(tmptype & SVf_READONLY);
733         retval = konst ? PL_constpadix : PL_padix;
734         for (;;) {
735             /*
736              * Entries that close over unavailable variables
737              * in outer subs contain values not marked PADMY.
738              * Thus we must skip, not just pad values that are
739              * marked as current pad values, but also those with names.
740              * If pad_reset is enabled, ‘current’ means different
741              * things depending on whether we are allocating a con-
742              * stant or a target.  For a target, things marked PADTMP
743              * can be reused; not so for constants.
744              */
745             PADNAME *pn;
746             if (++retval <= names_fill &&
747                    (pn = names[retval]) && PadnamePV(pn))
748                 continue;
749             sv = *av_fetch_simple(PL_comppad, retval, TRUE);
750             if (!(SvFLAGS(sv) &
751 #ifdef USE_PAD_RESET
752                     (konst ? SVs_PADTMP : 0)
753 #else
754                     SVs_PADTMP
755 #endif
756                  ))
757                 break;
758         }
759         if (konst) {
760             padnamelist_store(PL_comppad_name, retval, &PL_padname_const);
761             tmptype &= ~SVf_READONLY;
762             tmptype |= SVs_PADTMP;
763         }
764         *(konst ? &PL_constpadix : &PL_padix) = retval;
765     }
766     SvFLAGS(sv) |= tmptype;
767     PL_curpad = AvARRAY(PL_comppad);
768 
769     DEBUG_X(PerlIO_printf(Perl_debug_log,
770           "Pad 0x%" UVxf "[0x%" UVxf "] alloc:   %ld for %s\n",
771           PTR2UV(PL_comppad), PTR2UV(PL_curpad), (long) retval,
772           PL_op_name[optype]));
773 #ifdef DEBUG_LEAKING_SCALARS
774     sv->sv_debug_optype = optype;
775     sv->sv_debug_inpad = 1;
776 #endif
777     return retval;
778 }
779 
780 /*
781 =for apidoc pad_add_anon
782 
783 Allocates a place in the currently-compiling pad (via L</pad_alloc>)
784 for an anonymous function that is lexically scoped inside the
785 currently-compiling function.
786 The function C<func> is linked into the pad, and its C<CvOUTSIDE> link
787 to the outer scope is weakened to avoid a reference loop.
788 
789 One reference count is stolen, so you may need to do C<SvREFCNT_inc(func)>.
790 
791 C<optype> should be an opcode indicating the type of operation that the
792 pad entry is to support.  This doesn't affect operational semantics,
793 but is used for debugging.
794 
795 =cut
796 */
797 
798 PADOFFSET
799 Perl_pad_add_anon(pTHX_ CV* func, I32 optype)
800 {
801     PADOFFSET ix;
802     PADNAME * const name = newPADNAMEpvn("&", 1);
803 
804     PERL_ARGS_ASSERT_PAD_ADD_ANON;
805     assert (SvTYPE(func) == SVt_PVCV);
806 
807     pad_peg("add_anon");
808     /* These two aren't used; just make sure they're not equal to
809      * PERL_PADSEQ_INTRO.  They should be 0 by default.  */
810     assert(COP_SEQ_RANGE_LOW (name) != PERL_PADSEQ_INTRO);
811     assert(COP_SEQ_RANGE_HIGH(name) != PERL_PADSEQ_INTRO);
812     ix = pad_alloc(optype, SVs_PADMY);
813     padnamelist_store(PL_comppad_name, ix, name);
814     av_store(PL_comppad, ix, (SV*)func);
815 
816     /* to avoid ref loops, we never have parent + child referencing each
817      * other simultaneously */
818     if (CvOUTSIDE(func)) {
819         assert(!CvWEAKOUTSIDE(func));
820         CvWEAKOUTSIDE_on(func);
821         SvREFCNT_dec_NN(CvOUTSIDE(func));
822     }
823     return ix;
824 }
825 
826 void
827 Perl_pad_add_weakref(pTHX_ CV* func)
828 {
829     const PADOFFSET ix = pad_alloc(OP_NULL, SVs_PADMY);
830     PADNAME * const name = newPADNAMEpvn("&", 1);
831     SV * const rv = newRV_inc((SV *)func);
832 
833     PERL_ARGS_ASSERT_PAD_ADD_WEAKREF;
834 
835     /* These two aren't used; just make sure they're not equal to
836      * PERL_PADSEQ_INTRO.  They should be 0 by default.  */
837     assert(COP_SEQ_RANGE_LOW (name) != PERL_PADSEQ_INTRO);
838     assert(COP_SEQ_RANGE_HIGH(name) != PERL_PADSEQ_INTRO);
839     padnamelist_store(PL_comppad_name, ix, name);
840     sv_rvweaken(rv);
841     av_store(PL_comppad, ix, rv);
842 }
843 
844 /*
845 =for apidoc pad_check_dup
846 
847 Check for duplicate declarations: report any of:
848 
849      * a 'my' in the current scope with the same name;
850      * an 'our' (anywhere in the pad) with the same name and the
851        same stash as 'ourstash'
852 
853 C<is_our> indicates that the name to check is an C<"our"> declaration.
854 
855 =cut
856 */
857 
858 STATIC void
859 S_pad_check_dup(pTHX_ PADNAME *name, U32 flags, const HV *ourstash)
860 {
861     PADNAME	**svp;
862     PADOFFSET	top, off;
863     const U32	is_our = flags & padadd_OUR;
864 
865     PERL_ARGS_ASSERT_PAD_CHECK_DUP;
866 
867     ASSERT_CURPAD_ACTIVE("pad_check_dup");
868 
869     assert((flags & ~padadd_OUR) == 0);
870 
871     if (PadnamelistMAX(PL_comppad_name) < 0 || !ckWARN(WARN_SHADOW))
872         return; /* nothing to check */
873 
874     svp = PadnamelistARRAY(PL_comppad_name);
875     top = PadnamelistMAX(PL_comppad_name);
876     /* check the current scope */
877     for (off = top; off > PL_comppad_name_floor; off--) {
878         PADNAME * const sv = svp[off];
879         if (sv
880             && PadnameLEN(sv) == PadnameLEN(name)
881             && !PadnameOUTER(sv)
882             && (   COP_SEQ_RANGE_LOW(sv)  == PERL_PADSEQ_INTRO
883                 || COP_SEQ_RANGE_HIGH(sv) == PERL_PADSEQ_INTRO)
884             && memEQ(PadnamePV(sv), PadnamePV(name), PadnameLEN(name)))
885         {
886             if (is_our && (SvPAD_OUR(sv)))
887                 break; /* "our" masking "our" */
888             /* diag_listed_as: "%s" variable %s masks earlier declaration in same %s */
889             Perl_warner(aTHX_ packWARN(WARN_SHADOW),
890                 "\"%s\" %s %" PNf " masks earlier declaration in same %s",
891                 (   is_our                         ? "our"   :
892                     PL_parser->in_my == KEY_my     ? "my"    :
893                     PL_parser->in_my == KEY_sigvar ? "my"    :
894                                                      "state" ),
895                 *PadnamePV(sv) == '&' ? "subroutine" : "variable",
896                 PNfARG(sv),
897                 (COP_SEQ_RANGE_HIGH(sv) == PERL_PADSEQ_INTRO
898                     ? "scope" : "statement"));
899             --off;
900             break;
901         }
902     }
903     /* check the rest of the pad */
904     if (is_our) {
905         while (off > 0) {
906             PADNAME * const sv = svp[off];
907             if (sv
908                 && PadnameLEN(sv) == PadnameLEN(name)
909                 && !PadnameOUTER(sv)
910                 && (   COP_SEQ_RANGE_LOW(sv)  == PERL_PADSEQ_INTRO
911                     || COP_SEQ_RANGE_HIGH(sv) == PERL_PADSEQ_INTRO)
912                 && SvOURSTASH(sv) == ourstash
913                 && memEQ(PadnamePV(sv), PadnamePV(name), PadnameLEN(name)))
914             {
915                 Perl_warner(aTHX_ packWARN(WARN_SHADOW),
916                     "\"our\" variable %" PNf " redeclared", PNfARG(sv));
917                 if (off <= PL_comppad_name_floor)
918                     Perl_warner(aTHX_ packWARN(WARN_SHADOW),
919                         "\t(Did you mean \"local\" instead of \"our\"?)\n");
920                 break;
921             }
922             --off;
923         }
924     }
925 }
926 
927 
928 /*
929 =for apidoc pad_findmy_pvn
930 
931 Given the name of a lexical variable, find its position in the
932 currently-compiling pad.
933 C<namepv>/C<namelen> specify the variable's name, including leading sigil.
934 C<flags> is reserved and must be zero.
935 If it is not in the current pad but appears in the pad of any lexically
936 enclosing scope, then a pseudo-entry for it is added in the current pad.
937 Returns the offset in the current pad,
938 or C<NOT_IN_PAD> if no such lexical is in scope.
939 
940 =cut
941 */
942 
943 PADOFFSET
944 Perl_pad_findmy_pvn(pTHX_ const char *namepv, STRLEN namelen, U32 flags)
945 {
946     PADNAME *out_pn;
947     int out_flags;
948     PADOFFSET offset;
949     const PADNAMELIST *namelist;
950     PADNAME **name_p;
951 
952     PERL_ARGS_ASSERT_PAD_FINDMY_PVN;
953 
954     pad_peg("pad_findmy_pvn");
955 
956     if (flags)
957         Perl_croak(aTHX_ "panic: pad_findmy_pvn illegal flag bits 0x%" UVxf,
958                    (UV)flags);
959 
960     /* compilation errors can zero PL_compcv */
961     if (!PL_compcv)
962         return NOT_IN_PAD;
963 
964     offset = pad_findlex(namepv, namelen, flags,
965                 PL_compcv, PL_cop_seqmax, 1, NULL, &out_pn, &out_flags);
966     if (offset != NOT_IN_PAD)
967         return offset;
968 
969     /* Skip the ‘our’ hack for subroutines, as the warning does not apply.
970      */
971     if (*namepv == '&') return NOT_IN_PAD;
972 
973     /* look for an our that's being introduced; this allows
974      *    our $foo = 0 unless defined $foo;
975      * to not give a warning. (Yes, this is a hack) */
976 
977     namelist = PadlistNAMES(CvPADLIST(PL_compcv));
978     name_p = PadnamelistARRAY(namelist);
979     for (offset = PadnamelistMAXNAMED(namelist); offset > 0; offset--) {
980         const PADNAME * const name = name_p[offset];
981         if (name && PadnameLEN(name) == namelen
982             && !PadnameOUTER(name)
983             && (PadnameIsOUR(name))
984             && (  PadnamePV(name) == namepv
985                || memEQ(PadnamePV(name), namepv, namelen)  )
986             && COP_SEQ_RANGE_LOW(name) == PERL_PADSEQ_INTRO
987         )
988             return offset;
989     }
990     return NOT_IN_PAD;
991 }
992 
993 /*
994 =for apidoc pad_findmy_pv
995 
996 Exactly like L</pad_findmy_pvn>, but takes a nul-terminated string
997 instead of a string/length pair.
998 
999 =cut
1000 */
1001 
1002 PADOFFSET
1003 Perl_pad_findmy_pv(pTHX_ const char *name, U32 flags)
1004 {
1005     PERL_ARGS_ASSERT_PAD_FINDMY_PV;
1006     return pad_findmy_pvn(name, strlen(name), flags);
1007 }
1008 
1009 /*
1010 =for apidoc pad_findmy_sv
1011 
1012 Exactly like L</pad_findmy_pvn>, but takes the name string in the form
1013 of an SV instead of a string/length pair.
1014 
1015 =cut
1016 */
1017 
1018 PADOFFSET
1019 Perl_pad_findmy_sv(pTHX_ SV *name, U32 flags)
1020 {
1021     char *namepv;
1022     STRLEN namelen;
1023     PERL_ARGS_ASSERT_PAD_FINDMY_SV;
1024     namepv = SvPVutf8(name, namelen);
1025     return pad_findmy_pvn(namepv, namelen, flags);
1026 }
1027 
1028 /*
1029 =for apidoc find_rundefsvoffset
1030 
1031 Until the lexical C<$_> feature was removed, this function would
1032 find the position of the lexical C<$_> in the pad of the
1033 currently-executing function and return the offset in the current pad,
1034 or C<NOT_IN_PAD>.
1035 
1036 Now it always returns C<NOT_IN_PAD>.
1037 
1038 =cut
1039 */
1040 
1041 PADOFFSET
1042 Perl_find_rundefsvoffset(pTHX)
1043 {
1044     PERL_UNUSED_CONTEXT; /* Can we just remove the pTHX from the sig? */
1045     return NOT_IN_PAD;
1046 }
1047 
1048 /*
1049 =for apidoc find_rundefsv
1050 
1051 Returns the global variable C<$_>.
1052 
1053 =cut
1054 */
1055 
1056 SV *
1057 Perl_find_rundefsv(pTHX)
1058 {
1059     return DEFSV;
1060 }
1061 
1062 /*
1063 =for apidoc pad_findlex
1064 
1065 Find a named lexical anywhere in a chain of nested pads.  Add fake entries
1066 in the inner pads if it's found in an outer one.
1067 
1068 Returns the offset in the bottom pad of the lex or the fake lex.
1069 C<cv> is the CV in which to start the search, and seq is the current C<cop_seq>
1070 to match against.  If C<warn> is true, print appropriate warnings.  The C<out_>*
1071 vars return values, and so are pointers to where the returned values
1072 should be stored.  C<out_capture>, if non-null, requests that the innermost
1073 instance of the lexical is captured; C<out_name> is set to the innermost
1074 matched pad name or fake pad name; C<out_flags> returns the flags normally
1075 associated with the C<PARENT_FAKELEX_FLAGS> field of a fake pad name.
1076 
1077 Note that C<pad_findlex()> is recursive; it recurses up the chain of CVs,
1078 then comes back down, adding fake entries
1079 as it goes.  It has to be this way
1080 because fake names in anon prototypes have to store in C<xpadn_low> the
1081 index into the parent pad.
1082 
1083 =cut
1084 */
1085 
1086 /* the CV has finished being compiled. This is not a sufficient test for
1087  * all CVs (eg XSUBs), but suffices for the CVs found in a lexical chain */
1088 #define CvCOMPILED(cv)	CvROOT(cv)
1089 
1090 /* the CV does late binding of its lexicals */
1091 #define CvLATE(cv) (CvANON(cv) || CvCLONE(cv) || SvTYPE(cv) == SVt_PVFM)
1092 
1093 static void
1094 S_unavailable(pTHX_ PADNAME *name)
1095 {
1096     /* diag_listed_as: Variable "%s" is not available */
1097     Perl_ck_warner(aTHX_ packWARN(WARN_CLOSURE),
1098                         "%s \"%" PNf "\" is not available",
1099                          *PadnamePV(name) == '&'
1100                                          ? "Subroutine"
1101                                          : "Variable",
1102                          PNfARG(name));
1103 }
1104 
1105 STATIC PADOFFSET
1106 S_pad_findlex(pTHX_ const char *namepv, STRLEN namelen, U32 flags, const CV* cv, U32 seq,
1107         int warn, SV** out_capture, PADNAME** out_name, int *out_flags)
1108 {
1109     PADOFFSET offset, new_offset;
1110     SV *new_capture;
1111     SV **new_capturep;
1112     const PADLIST * const padlist = CvPADLIST(cv);
1113     const bool staleok = !!(flags & padadd_STALEOK);
1114 
1115     PERL_ARGS_ASSERT_PAD_FINDLEX;
1116 
1117     flags &= ~ padadd_STALEOK; /* one-shot flag */
1118     if (flags)
1119         Perl_croak(aTHX_ "panic: pad_findlex illegal flag bits 0x%" UVxf,
1120                    (UV)flags);
1121 
1122     *out_flags = 0;
1123 
1124     DEBUG_Xv(PerlIO_printf(Perl_debug_log,
1125         "Pad findlex cv=0x%" UVxf " searching \"%.*s\" seq=%d%s\n",
1126                            PTR2UV(cv), (int)namelen, namepv, (int)seq,
1127         out_capture ? " capturing" : "" ));
1128 
1129     /* first, search this pad */
1130 
1131     if (padlist) { /* not an undef CV */
1132         PADOFFSET fake_offset = 0;
1133         const PADNAMELIST * const names = PadlistNAMES(padlist);
1134         PADNAME * const * const name_p = PadnamelistARRAY(names);
1135 
1136         for (offset = PadnamelistMAXNAMED(names); offset > 0; offset--) {
1137             const PADNAME * const name = name_p[offset];
1138             if (name && PadnameLEN(name) == namelen
1139                      && (  PadnamePV(name) == namepv
1140                         || memEQ(PadnamePV(name), namepv, namelen)  ))
1141             {
1142                 if (PadnameOUTER(name)) {
1143                     fake_offset = offset; /* in case we don't find a real one */
1144                     continue;
1145                 }
1146                 if (PadnameIN_SCOPE(name, seq))
1147                     break;
1148             }
1149         }
1150 
1151         if (offset > 0 || fake_offset > 0 ) { /* a match! */
1152             if (offset > 0) { /* not fake */
1153                 fake_offset = 0;
1154                 *out_name = name_p[offset]; /* return the name */
1155 
1156                 /* set PAD_FAKELEX_MULTI if this lex can have multiple
1157                  * instances. For now, we just test !CvUNIQUE(cv), but
1158                  * ideally, we should detect my's declared within loops
1159                  * etc - this would allow a wider range of 'not stayed
1160                  * shared' warnings. We also treated already-compiled
1161                  * lexes as not multi as viewed from evals. */
1162 
1163                 *out_flags = CvANON(cv) ?
1164                         PAD_FAKELEX_ANON :
1165                             (!CvUNIQUE(cv) && ! CvCOMPILED(cv))
1166                                 ? PAD_FAKELEX_MULTI : 0;
1167 
1168                 DEBUG_Xv(PerlIO_printf(Perl_debug_log,
1169                     "Pad findlex cv=0x%" UVxf " matched: offset=%ld (%lu,%lu)\n",
1170                     PTR2UV(cv), (long)offset,
1171                     (unsigned long)COP_SEQ_RANGE_LOW(*out_name),
1172                     (unsigned long)COP_SEQ_RANGE_HIGH(*out_name)));
1173             }
1174             else { /* fake match */
1175                 offset = fake_offset;
1176                 *out_name = name_p[offset]; /* return the name */
1177                 *out_flags = PARENT_FAKELEX_FLAGS(*out_name);
1178                 DEBUG_Xv(PerlIO_printf(Perl_debug_log,
1179                     "Pad findlex cv=0x%" UVxf " matched: offset=%ld flags=0x%lx index=%lu\n",
1180                     PTR2UV(cv), (long)offset, (unsigned long)*out_flags,
1181                     (unsigned long) PARENT_PAD_INDEX(*out_name)
1182                 ));
1183             }
1184 
1185             /* return the lex? */
1186 
1187             if (out_capture) {
1188 
1189                 /* our ? */
1190                 if (PadnameIsOUR(*out_name)) {
1191                     *out_capture = NULL;
1192                     return offset;
1193                 }
1194 
1195                 /* trying to capture from an anon prototype? */
1196                 if (CvCOMPILED(cv)
1197                         ? CvANON(cv) && CvCLONE(cv) && !CvCLONED(cv)
1198                         : *out_flags & PAD_FAKELEX_ANON)
1199                 {
1200                     if (warn)
1201                         S_unavailable(aTHX_
1202                                       *out_name);
1203 
1204                     *out_capture = NULL;
1205                 }
1206 
1207                 /* real value */
1208                 else {
1209                     int newwarn = warn;
1210                     if (!CvCOMPILED(cv) && (*out_flags & PAD_FAKELEX_MULTI)
1211                          && !PadnameIsSTATE(name_p[offset])
1212                          && warn && ckWARN(WARN_CLOSURE)) {
1213                         newwarn = 0;
1214                         /* diag_listed_as: Variable "%s" will not stay
1215                                            shared */
1216                         Perl_warner(aTHX_ packWARN(WARN_CLOSURE),
1217                             "%s \"%" UTF8f "\" will not stay shared",
1218                              *namepv == '&' ? "Subroutine" : "Variable",
1219                              UTF8fARG(1, namelen, namepv));
1220                     }
1221 
1222                     if (fake_offset && CvANON(cv)
1223                             && CvCLONE(cv) &&!CvCLONED(cv))
1224                     {
1225                         PADNAME *n;
1226                         /* not yet caught - look further up */
1227                         DEBUG_Xv(PerlIO_printf(Perl_debug_log,
1228                             "Pad findlex cv=0x%" UVxf " chasing lex in outer pad\n",
1229                             PTR2UV(cv)));
1230                         n = *out_name;
1231                         (void) pad_findlex(namepv, namelen, flags, CvOUTSIDE(cv),
1232                             CvOUTSIDE_SEQ(cv),
1233                             newwarn, out_capture, out_name, out_flags);
1234                         *out_name = n;
1235                         return offset;
1236                     }
1237 
1238                     *out_capture = AvARRAY(PadlistARRAY(padlist)[
1239                                     CvDEPTH(cv) ? CvDEPTH(cv) : 1])[offset];
1240                     DEBUG_Xv(PerlIO_printf(Perl_debug_log,
1241                         "Pad findlex cv=0x%" UVxf " found lex=0x%" UVxf "\n",
1242                         PTR2UV(cv), PTR2UV(*out_capture)));
1243 
1244                     if (SvPADSTALE(*out_capture)
1245                         && (!CvDEPTH(cv) || !staleok)
1246                         && !PadnameIsSTATE(name_p[offset]))
1247                     {
1248                         S_unavailable(aTHX_
1249                                       name_p[offset]);
1250                         *out_capture = NULL;
1251                     }
1252                 }
1253                 if (!*out_capture) {
1254                     if (namelen != 0 && *namepv == '@')
1255                         *out_capture = newSV_type_mortal(SVt_PVAV);
1256                     else if (namelen != 0 && *namepv == '%')
1257                         *out_capture = newSV_type_mortal(SVt_PVHV);
1258                     else if (namelen != 0 && *namepv == '&')
1259                         *out_capture = newSV_type_mortal(SVt_PVCV);
1260                     else
1261                         *out_capture = newSV_type_mortal(SVt_NULL);
1262                 }
1263             }
1264 
1265             return offset;
1266         }
1267     }
1268 
1269     /* it's not in this pad - try above */
1270 
1271     if (!CvOUTSIDE(cv))
1272         return NOT_IN_PAD;
1273 
1274     /* out_capture non-null means caller wants us to capture lex; in
1275      * addition we capture ourselves unless it's an ANON/format */
1276     new_capturep = out_capture ? out_capture :
1277                 CvLATE(cv) ? NULL : &new_capture;
1278 
1279     offset = pad_findlex(namepv, namelen,
1280                 flags | padadd_STALEOK*(new_capturep == &new_capture),
1281                 CvOUTSIDE(cv), CvOUTSIDE_SEQ(cv), 1,
1282                 new_capturep, out_name, out_flags);
1283     if (offset == NOT_IN_PAD)
1284         return NOT_IN_PAD;
1285 
1286     /* found in an outer CV. Add appropriate fake entry to this pad */
1287 
1288     /* don't add new fake entries (via eval) to CVs that we have already
1289      * finished compiling, or to undef CVs */
1290     if (CvCOMPILED(cv) || !padlist)
1291         return 0; /* this dummy (and invalid) value isnt used by the caller */
1292 
1293     {
1294         PADNAME *new_name = newPADNAMEouter(*out_name);
1295         PADNAMELIST * const ocomppad_name = PL_comppad_name;
1296         PAD * const ocomppad = PL_comppad;
1297         PL_comppad_name = PadlistNAMES(padlist);
1298         PL_comppad = PadlistARRAY(padlist)[1];
1299         PL_curpad = AvARRAY(PL_comppad);
1300 
1301         new_offset
1302             = pad_alloc_name(new_name,
1303                               PadnameIsSTATE(*out_name) ? padadd_STATE : 0,
1304                               PadnameTYPE(*out_name),
1305                               PadnameOURSTASH(*out_name)
1306                               );
1307 
1308         DEBUG_Xv(PerlIO_printf(Perl_debug_log,
1309                                "Pad addname: %ld \"%.*s\" FAKE\n",
1310                                (long)new_offset,
1311                                (int) PadnameLEN(new_name),
1312                                PadnamePV(new_name)));
1313         PARENT_FAKELEX_FLAGS_set(new_name, *out_flags);
1314 
1315         PARENT_PAD_INDEX_set(new_name, 0);
1316         if (PadnameIsOUR(new_name)) {
1317             NOOP;   /* do nothing */
1318         }
1319         else if (CvLATE(cv)) {
1320             /* delayed creation - just note the offset within parent pad */
1321             PARENT_PAD_INDEX_set(new_name, offset);
1322             CvCLONE_on(cv);
1323         }
1324         else {
1325             /* immediate creation - capture outer value right now */
1326             av_store(PL_comppad, new_offset, SvREFCNT_inc(*new_capturep));
1327             /* But also note the offset, as newMYSUB needs it */
1328             PARENT_PAD_INDEX_set(new_name, offset);
1329             DEBUG_Xv(PerlIO_printf(Perl_debug_log,
1330                 "Pad findlex cv=0x%" UVxf " saved captured sv 0x%" UVxf " at offset %ld\n",
1331                 PTR2UV(cv), PTR2UV(*new_capturep), (long)new_offset));
1332         }
1333         *out_name = new_name;
1334         *out_flags = PARENT_FAKELEX_FLAGS(new_name);
1335 
1336         PL_comppad_name = ocomppad_name;
1337         PL_comppad = ocomppad;
1338         PL_curpad = ocomppad ? AvARRAY(ocomppad) : NULL;
1339     }
1340     return new_offset;
1341 }
1342 
1343 #ifdef DEBUGGING
1344 
1345 /*
1346 =for apidoc pad_sv
1347 
1348 Get the value at offset C<po> in the current (compiling or executing) pad.
1349 Use macro C<PAD_SV> instead of calling this function directly.
1350 
1351 =cut
1352 */
1353 
1354 SV *
1355 Perl_pad_sv(pTHX_ PADOFFSET po)
1356 {
1357     ASSERT_CURPAD_ACTIVE("pad_sv");
1358 
1359     if (!po)
1360         Perl_croak(aTHX_ "panic: pad_sv po");
1361     DEBUG_X(PerlIO_printf(Perl_debug_log,
1362         "Pad 0x%" UVxf "[0x%" UVxf "] sv:      %ld sv=0x%" UVxf "\n",
1363         PTR2UV(PL_comppad), PTR2UV(PL_curpad), (long)po, PTR2UV(PL_curpad[po]))
1364     );
1365     return PL_curpad[po];
1366 }
1367 
1368 /*
1369 =for apidoc pad_setsv
1370 
1371 Set the value at offset C<po> in the current (compiling or executing) pad.
1372 Use the macro C<PAD_SETSV()> rather than calling this function directly.
1373 
1374 =cut
1375 */
1376 
1377 void
1378 Perl_pad_setsv(pTHX_ PADOFFSET po, SV* sv)
1379 {
1380     PERL_ARGS_ASSERT_PAD_SETSV;
1381 
1382     ASSERT_CURPAD_ACTIVE("pad_setsv");
1383 
1384     DEBUG_X(PerlIO_printf(Perl_debug_log,
1385         "Pad 0x%" UVxf "[0x%" UVxf "] setsv:   %ld sv=0x%" UVxf "\n",
1386         PTR2UV(PL_comppad), PTR2UV(PL_curpad), (long)po, PTR2UV(sv))
1387     );
1388     PL_curpad[po] = sv;
1389 }
1390 
1391 #endif /* DEBUGGING */
1392 
1393 /*
1394 =for apidoc pad_block_start
1395 
1396 Update the pad compilation state variables on entry to a new block.
1397 
1398 =cut
1399 */
1400 
1401 void
1402 Perl_pad_block_start(pTHX_ int full)
1403 {
1404     ASSERT_CURPAD_ACTIVE("pad_block_start");
1405     SAVESTRLEN(PL_comppad_name_floor);
1406     PL_comppad_name_floor = PadnamelistMAX(PL_comppad_name);
1407     if (full)
1408         PL_comppad_name_fill = PL_comppad_name_floor;
1409     if (PL_comppad_name_floor < 0)
1410         PL_comppad_name_floor = 0;
1411     SAVESTRLEN(PL_min_intro_pending);
1412     SAVESTRLEN(PL_max_intro_pending);
1413     PL_min_intro_pending = 0;
1414     SAVESTRLEN(PL_comppad_name_fill);
1415     SAVESTRLEN(PL_padix_floor);
1416     /* PL_padix_floor is what PL_padix is reset to at the start of each
1417        statement, by pad_reset().  We set it when entering a new scope
1418        to keep things like this working:
1419             print "$foo$bar", do { this(); that() . "foo" };
1420        We must not let "$foo$bar" and the later concatenation share the
1421        same target.  */
1422     PL_padix_floor = PL_padix;
1423     PL_pad_reset_pending = FALSE;
1424 }
1425 
1426 /*
1427 =for apidoc intro_my
1428 
1429 "Introduce" C<my> variables to visible status.  This is called during parsing
1430 at the end of each statement to make lexical variables visible to subsequent
1431 statements.
1432 
1433 =cut
1434 */
1435 
1436 U32
1437 Perl_intro_my(pTHX)
1438 {
1439     PADNAME **svp;
1440     PADOFFSET i;
1441     U32 seq;
1442 
1443     ASSERT_CURPAD_ACTIVE("intro_my");
1444     if (PL_compiling.cop_seq) {
1445         seq = PL_compiling.cop_seq;
1446         PL_compiling.cop_seq = 0;
1447     }
1448     else
1449         seq = PL_cop_seqmax;
1450     if (! PL_min_intro_pending)
1451         return seq;
1452 
1453     svp = PadnamelistARRAY(PL_comppad_name);
1454     for (i = PL_min_intro_pending; i <= PL_max_intro_pending; i++) {
1455         PADNAME * const sv = svp[i];
1456 
1457         if (sv && PadnameLEN(sv) && !PadnameOUTER(sv)
1458             && COP_SEQ_RANGE_LOW(sv) == PERL_PADSEQ_INTRO)
1459         {
1460             COP_SEQ_RANGE_HIGH_set(sv, PERL_PADSEQ_INTRO); /* Don't know scope end yet. */
1461             COP_SEQ_RANGE_LOW_set(sv, PL_cop_seqmax);
1462             DEBUG_Xv(PerlIO_printf(Perl_debug_log,
1463                 "Pad intromy: %ld \"%s\", (%lu,%lu)\n",
1464                 (long)i, PadnamePV(sv),
1465                 (unsigned long)COP_SEQ_RANGE_LOW(sv),
1466                 (unsigned long)COP_SEQ_RANGE_HIGH(sv))
1467             );
1468         }
1469     }
1470     COP_SEQMAX_INC;
1471     PL_min_intro_pending = 0;
1472     PL_comppad_name_fill = PL_max_intro_pending; /* Needn't search higher */
1473     DEBUG_Xv(PerlIO_printf(Perl_debug_log,
1474                 "Pad intromy: seq -> %ld\n", (long)(PL_cop_seqmax)));
1475 
1476     return seq;
1477 }
1478 
1479 /*
1480 =for apidoc pad_leavemy
1481 
1482 Cleanup at end of scope during compilation: set the max seq number for
1483 lexicals in this scope and warn of any lexicals that never got introduced.
1484 
1485 =cut
1486 */
1487 
1488 OP *
1489 Perl_pad_leavemy(pTHX)
1490 {
1491     PADOFFSET off;
1492     OP *o = NULL;
1493     PADNAME * const * const svp = PadnamelistARRAY(PL_comppad_name);
1494 
1495     PL_pad_reset_pending = FALSE;
1496 
1497     ASSERT_CURPAD_ACTIVE("pad_leavemy");
1498     if (PL_min_intro_pending && PL_comppad_name_fill < PL_min_intro_pending) {
1499         for (off = PL_max_intro_pending; off >= PL_min_intro_pending; off--) {
1500             const PADNAME * const name = svp[off];
1501             if (name && PadnameLEN(name) && !PadnameOUTER(name))
1502                 Perl_ck_warner_d(aTHX_ packWARN(WARN_INTERNAL),
1503                                       "%" PNf " never introduced",
1504                                        PNfARG(name));
1505         }
1506     }
1507     /* "Deintroduce" my variables that are leaving with this scope. */
1508     for (off = PadnamelistMAX(PL_comppad_name);
1509          off > PL_comppad_name_fill; off--) {
1510         PADNAME * const sv = svp[off];
1511         if (sv && PadnameLEN(sv) && !PadnameOUTER(sv)
1512             && COP_SEQ_RANGE_HIGH(sv) == PERL_PADSEQ_INTRO)
1513         {
1514             COP_SEQ_RANGE_HIGH_set(sv, PL_cop_seqmax);
1515             DEBUG_Xv(PerlIO_printf(Perl_debug_log,
1516                 "Pad leavemy: %ld \"%s\", (%lu,%lu)\n",
1517                 (long)off, PadnamePV(sv),
1518                 (unsigned long)COP_SEQ_RANGE_LOW(sv),
1519                 (unsigned long)COP_SEQ_RANGE_HIGH(sv))
1520             );
1521             if (!PadnameIsSTATE(sv) && !PadnameIsOUR(sv)
1522              && *PadnamePV(sv) == '&' && PadnameLEN(sv) > 1) {
1523                 OP *kid = newOP(OP_INTROCV, 0);
1524                 kid->op_targ = off;
1525                 o = op_prepend_elem(OP_LINESEQ, kid, o);
1526             }
1527         }
1528     }
1529     COP_SEQMAX_INC;
1530     DEBUG_Xv(PerlIO_printf(Perl_debug_log,
1531             "Pad leavemy: seq = %ld\n", (long)PL_cop_seqmax));
1532     return o;
1533 }
1534 
1535 /*
1536 =for apidoc pad_swipe
1537 
1538 Abandon the tmp in the current pad at offset C<po> and replace with a
1539 new one.
1540 
1541 =cut
1542 */
1543 
1544 void
1545 Perl_pad_swipe(pTHX_ PADOFFSET po, bool refadjust)
1546 {
1547     ASSERT_CURPAD_LEGAL("pad_swipe");
1548     if (!PL_curpad)
1549         return;
1550     if (AvARRAY(PL_comppad) != PL_curpad)
1551         Perl_croak(aTHX_ "panic: pad_swipe curpad, %p!=%p",
1552                    AvARRAY(PL_comppad), PL_curpad);
1553     if (!po || ((SSize_t)po) > AvFILLp(PL_comppad))
1554         Perl_croak(aTHX_ "panic: pad_swipe po=%ld, fill=%ld",
1555                    (long)po, (long)AvFILLp(PL_comppad));
1556 
1557     DEBUG_X(PerlIO_printf(Perl_debug_log,
1558                 "Pad 0x%" UVxf "[0x%" UVxf "] swipe:   %ld\n",
1559                 PTR2UV(PL_comppad), PTR2UV(PL_curpad), (long)po));
1560 
1561     if (refadjust)
1562         SvREFCNT_dec(PL_curpad[po]);
1563 
1564 
1565     /* if pad tmps aren't shared between ops, then there's no need to
1566      * create a new tmp when an existing op is freed */
1567 #ifdef USE_PAD_RESET
1568     PL_curpad[po] = newSV_type(SVt_NULL);
1569     SvPADTMP_on(PL_curpad[po]);
1570 #else
1571     PL_curpad[po] = NULL;
1572 #endif
1573     if (PadnamelistMAX(PL_comppad_name) != -1
1574      && (PADOFFSET)PadnamelistMAX(PL_comppad_name) >= po) {
1575         if (PadnamelistARRAY(PL_comppad_name)[po]) {
1576             assert(!PadnameLEN(PadnamelistARRAY(PL_comppad_name)[po]));
1577         }
1578         PadnamelistARRAY(PL_comppad_name)[po] = &PL_padname_undef;
1579     }
1580     /* Use PL_constpadix here, not PL_padix.  The latter may have been
1581        reset by pad_reset.  We don’t want pad_alloc to have to scan the
1582        whole pad when allocating a constant. */
1583     if (po < PL_constpadix)
1584         PL_constpadix = po - 1;
1585 }
1586 
1587 /*
1588 =for apidoc pad_reset
1589 
1590 Mark all the current temporaries for reuse
1591 
1592 =cut
1593 */
1594 
1595 /* pad_reset() causes pad temp TARGs (operator targets) to be shared
1596  * between OPs from different statements.  During compilation, at the start
1597  * of each statement pad_reset resets PL_padix back to its previous value.
1598  * When allocating a target, pad_alloc begins its scan through the pad at
1599  * PL_padix+1.  */
1600 static void
1601 S_pad_reset(pTHX)
1602 {
1603 #ifdef USE_PAD_RESET
1604     if (AvARRAY(PL_comppad) != PL_curpad)
1605         Perl_croak(aTHX_ "panic: pad_reset curpad, %p!=%p",
1606                    AvARRAY(PL_comppad), PL_curpad);
1607 
1608     DEBUG_X(PerlIO_printf(Perl_debug_log,
1609             "Pad 0x%" UVxf "[0x%" UVxf "] reset:     padix %ld -> %ld",
1610             PTR2UV(PL_comppad), PTR2UV(PL_curpad),
1611                 (long)PL_padix, (long)PL_padix_floor
1612             )
1613     );
1614 
1615     if (!TAINTING_get) {	/* Can't mix tainted and non-tainted temporaries. */
1616         PL_padix = PL_padix_floor;
1617     }
1618 #endif
1619     PL_pad_reset_pending = FALSE;
1620 }
1621 
1622 /*
1623 =for apidoc pad_tidy
1624 
1625 Tidy up a pad at the end of compilation of the code to which it belongs.
1626 Jobs performed here are: remove most stuff from the pads of anonsub
1627 prototypes; give it a C<@_>; mark temporaries as such.  C<type> indicates
1628 the kind of subroutine:
1629 
1630     padtidy_SUB        ordinary subroutine
1631     padtidy_SUBCLONE   prototype for lexical closure
1632     padtidy_FORMAT     format
1633 
1634 =cut
1635 */
1636 
1637 void
1638 Perl_pad_tidy(pTHX_ padtidy_type type)
1639 {
1640 
1641     ASSERT_CURPAD_ACTIVE("pad_tidy");
1642 
1643     /* If this CV has had any 'eval-capable' ops planted in it:
1644      * i.e. it contains any of:
1645      *
1646      *     * eval '...',
1647      *     * //ee,
1648      *     * use re 'eval'; /$var/
1649      *     * /(?{..})/),
1650      *
1651      * Then any anon prototypes in the chain of CVs should be marked as
1652      * cloneable, so that for example the eval's CV in
1653      *
1654      *    sub { eval '$x' }
1655      *
1656      * gets the right CvOUTSIDE.  If running with -d, *any* sub may
1657      * potentially have an eval executed within it.
1658      */
1659 
1660     if (PL_cv_has_eval || PL_perldb) {
1661         const CV *cv;
1662         for (cv = PL_compcv ;cv; cv = CvOUTSIDE(cv)) {
1663             if (cv != PL_compcv && CvCOMPILED(cv))
1664                 break; /* no need to mark already-compiled code */
1665             if (CvANON(cv)) {
1666                 DEBUG_Xv(PerlIO_printf(Perl_debug_log,
1667                     "Pad clone on cv=0x%" UVxf "\n", PTR2UV(cv)));
1668                 CvCLONE_on(cv);
1669             }
1670             CvHASEVAL_on(cv);
1671         }
1672     }
1673 
1674     /* extend namepad to match curpad */
1675     if (PadnamelistMAX(PL_comppad_name) < AvFILLp(PL_comppad))
1676         padnamelist_store(PL_comppad_name, AvFILLp(PL_comppad), NULL);
1677 
1678     if (type == padtidy_SUBCLONE) {
1679         PADNAME ** const namep = PadnamelistARRAY(PL_comppad_name);
1680         PADOFFSET ix;
1681 
1682         for (ix = AvFILLp(PL_comppad); ix > 0; ix--) {
1683             PADNAME *namesv;
1684             if (!namep[ix]) namep[ix] = &PL_padname_undef;
1685 
1686             /*
1687              * The only things that a clonable function needs in its
1688              * pad are anonymous subs, constants and GVs.
1689              * The rest are created anew during cloning.
1690              */
1691             if (!PL_curpad[ix] || SvIMMORTAL(PL_curpad[ix]))
1692                 continue;
1693             namesv = namep[ix];
1694             if (!(PadnamePV(namesv) &&
1695                    (!PadnameLEN(namesv) || *PadnamePV(namesv) == '&')))
1696             {
1697                 SvREFCNT_dec(PL_curpad[ix]);
1698                 PL_curpad[ix] = NULL;
1699             }
1700         }
1701     }
1702     else if (type == padtidy_SUB) {
1703         AV * const av = newAV();			/* Will be @_ */
1704         av_store(PL_comppad, 0, MUTABLE_SV(av));
1705         AvREIFY_only(av);
1706     }
1707 
1708     if (type == padtidy_SUB || type == padtidy_FORMAT) {
1709         PADNAME ** const namep = PadnamelistARRAY(PL_comppad_name);
1710         PADOFFSET ix;
1711         for (ix = AvFILLp(PL_comppad); ix > 0; ix--) {
1712             if (!namep[ix]) namep[ix] = &PL_padname_undef;
1713             if (!PL_curpad[ix] || SvIMMORTAL(PL_curpad[ix]))
1714                 continue;
1715             if (SvPADMY(PL_curpad[ix]) && !PadnameOUTER(namep[ix])) {
1716                 /* This is a work around for how the current implementation of
1717                    ?{ } blocks in regexps interacts with lexicals.
1718 
1719                    One of our lexicals.
1720                    Can't do this on all lexicals, otherwise sub baz() won't
1721                    compile in
1722 
1723                    my $foo;
1724 
1725                    sub bar { ++$foo; }
1726 
1727                    sub baz { ++$foo; }
1728 
1729                    because completion of compiling &bar calling pad_tidy()
1730                    would cause (top level) $foo to be marked as stale, and
1731                    "no longer available".  */
1732                 SvPADSTALE_on(PL_curpad[ix]);
1733             }
1734         }
1735     }
1736     PL_curpad = AvARRAY(PL_comppad);
1737 }
1738 
1739 /*
1740 =for apidoc pad_free
1741 
1742 Free the SV at offset po in the current pad.
1743 
1744 =cut
1745 */
1746 
1747 void
1748 Perl_pad_free(pTHX_ PADOFFSET po)
1749 {
1750 #ifndef USE_PAD_RESET
1751     SV *sv;
1752 #endif
1753     ASSERT_CURPAD_LEGAL("pad_free");
1754     if (!PL_curpad)
1755         return;
1756     if (AvARRAY(PL_comppad) != PL_curpad)
1757         Perl_croak(aTHX_ "panic: pad_free curpad, %p!=%p",
1758                    AvARRAY(PL_comppad), PL_curpad);
1759     if (!po)
1760         Perl_croak(aTHX_ "panic: pad_free po");
1761 
1762     DEBUG_X(PerlIO_printf(Perl_debug_log,
1763             "Pad 0x%" UVxf "[0x%" UVxf "] free:    %ld\n",
1764             PTR2UV(PL_comppad), PTR2UV(PL_curpad), (long)po)
1765     );
1766 
1767 #ifndef USE_PAD_RESET
1768     sv = PL_curpad[po];
1769     if (sv && sv != &PL_sv_undef && !SvPADMY(sv))
1770         SvFLAGS(sv) &= ~SVs_PADTMP;
1771 
1772     if (po < PL_padix)
1773         PL_padix = po - 1;
1774 #endif
1775 }
1776 
1777 /*
1778 =for apidoc do_dump_pad
1779 
1780 Dump the contents of a padlist
1781 
1782 =cut
1783 */
1784 
1785 void
1786 Perl_do_dump_pad(pTHX_ I32 level, PerlIO *file, PADLIST *padlist, int full)
1787 {
1788     const PADNAMELIST *pad_name;
1789     const AV *pad;
1790     PADNAME **pname;
1791     SV **ppad;
1792     PADOFFSET ix;
1793 
1794     PERL_ARGS_ASSERT_DO_DUMP_PAD;
1795 
1796     if (!padlist) {
1797         return;
1798     }
1799     pad_name = PadlistNAMES(padlist);
1800     pad = PadlistARRAY(padlist)[1];
1801     pname = PadnamelistARRAY(pad_name);
1802     ppad = AvARRAY(pad);
1803     Perl_dump_indent(aTHX_ level, file,
1804             "PADNAME = 0x%" UVxf "(0x%" UVxf ") PAD = 0x%" UVxf "(0x%" UVxf ")\n",
1805             PTR2UV(pad_name), PTR2UV(pname), PTR2UV(pad), PTR2UV(ppad)
1806     );
1807 
1808     for (ix = 1; ix <= PadnamelistMAX(pad_name); ix++) {
1809         const PADNAME *namesv = pname[ix];
1810         if (namesv && !PadnameLEN(namesv)) {
1811             namesv = NULL;
1812         }
1813         if (namesv) {
1814             if (PadnameOUTER(namesv))
1815                 Perl_dump_indent(aTHX_ level+1, file,
1816                     "%2d. 0x%" UVxf "<%lu> FAKE \"%s\" flags=0x%lx index=%lu\n",
1817                     (int) ix,
1818                     PTR2UV(ppad[ix]),
1819                     (unsigned long) (ppad[ix] ? SvREFCNT(ppad[ix]) : 0),
1820                     PadnamePV(namesv),
1821                     (unsigned long)PARENT_FAKELEX_FLAGS(namesv),
1822                     (unsigned long)PARENT_PAD_INDEX(namesv)
1823 
1824                 );
1825             else
1826                 Perl_dump_indent(aTHX_ level+1, file,
1827                     "%2d. 0x%" UVxf "<%lu> (%lu,%lu) \"%s\"\n",
1828                     (int) ix,
1829                     PTR2UV(ppad[ix]),
1830                     (unsigned long) (ppad[ix] ? SvREFCNT(ppad[ix]) : 0),
1831                     (unsigned long)COP_SEQ_RANGE_LOW(namesv),
1832                     (unsigned long)COP_SEQ_RANGE_HIGH(namesv),
1833                     PadnamePV(namesv)
1834                 );
1835         }
1836         else if (full) {
1837             Perl_dump_indent(aTHX_ level+1, file,
1838                 "%2d. 0x%" UVxf "<%lu>\n",
1839                 (int) ix,
1840                 PTR2UV(ppad[ix]),
1841                 (unsigned long) (ppad[ix] ? SvREFCNT(ppad[ix]) : 0)
1842             );
1843         }
1844     }
1845 }
1846 
1847 #ifdef DEBUGGING
1848 
1849 /*
1850 =for apidoc cv_dump
1851 
1852 dump the contents of a CV
1853 
1854 =cut
1855 */
1856 
1857 STATIC void
1858 S_cv_dump(pTHX_ const CV *cv, const char *title)
1859 {
1860     const CV * const outside = CvOUTSIDE(cv);
1861 
1862     PERL_ARGS_ASSERT_CV_DUMP;
1863 
1864     PerlIO_printf(Perl_debug_log,
1865                   "  %s: CV=0x%" UVxf " (%s), OUTSIDE=0x%" UVxf " (%s)\n",
1866                   title,
1867                   PTR2UV(cv),
1868                   (CvANON(cv) ? "ANON"
1869                    : (SvTYPE(cv) == SVt_PVFM) ? "FORMAT"
1870                    : (cv == PL_main_cv) ? "MAIN"
1871                    : CvUNIQUE(cv) ? "UNIQUE"
1872                    : CvGV(cv) ? GvNAME(CvGV(cv)) : "UNDEFINED"),
1873                   PTR2UV(outside),
1874                   (!outside ? "null"
1875                    : CvANON(outside) ? "ANON"
1876                    : (outside == PL_main_cv) ? "MAIN"
1877                    : CvUNIQUE(outside) ? "UNIQUE"
1878                    : CvGV(outside) ? GvNAME(CvGV(outside)) : "UNDEFINED"));
1879 
1880     if (!CvISXSUB(cv)) {
1881         /* SVPADLIST(cv) will fail an assert if CvISXSUB(cv) is true,
1882          * and if the assert is removed this code will SEGV. XSUBs don't
1883          * have padlists I believe - Yves */
1884         PADLIST* const padlist = CvPADLIST(cv);
1885         PerlIO_printf(Perl_debug_log,
1886                     "    PADLIST = 0x%" UVxf "\n", PTR2UV(padlist));
1887         do_dump_pad(1, Perl_debug_log, padlist, 1);
1888     }
1889 }
1890 
1891 #endif /* DEBUGGING */
1892 
1893 /*
1894 =for apidoc cv_clone
1895 
1896 Clone a CV, making a lexical closure.  C<proto> supplies the prototype
1897 of the function: its code, pad structure, and other attributes.
1898 The prototype is combined with a capture of outer lexicals to which the
1899 code refers, which are taken from the currently-executing instance of
1900 the immediately surrounding code.
1901 
1902 =cut
1903 */
1904 
1905 static CV *S_cv_clone(pTHX_ CV *proto, CV *cv, CV *outside, HV *cloned);
1906 
1907 static CV *
1908 S_cv_clone_pad(pTHX_ CV *proto, CV *cv, CV *outside, HV *cloned,
1909                      bool newcv)
1910 {
1911     PADOFFSET ix;
1912     PADLIST* const protopadlist = CvPADLIST(proto);
1913     PADNAMELIST *const protopad_name = PadlistNAMES(protopadlist);
1914     const PAD *const protopad = PadlistARRAY(protopadlist)[1];
1915     PADNAME** const pname = PadnamelistARRAY(protopad_name);
1916     SV** const ppad = AvARRAY(protopad);
1917     const PADOFFSET fname = PadnamelistMAX(protopad_name);
1918     const PADOFFSET fpad = AvFILLp(protopad);
1919     SV** outpad;
1920     long depth;
1921     U32 subclones = 0;
1922     bool trouble = FALSE;
1923 
1924     assert(!CvUNIQUE(proto));
1925 
1926     /* Anonymous subs have a weak CvOUTSIDE pointer, so its value is not
1927      * reliable.  The currently-running sub is always the one we need to
1928      * close over.
1929      * For my subs, the currently-running sub may not be the one we want.
1930      * We have to check whether it is a clone of CvOUTSIDE.
1931      * Note that in general for formats, CvOUTSIDE != find_runcv.
1932      * Since formats may be nested inside closures, CvOUTSIDE may point
1933      * to a prototype; we instead want the cloned parent who called us.
1934      */
1935 
1936     if (!outside) {
1937       if (CvWEAKOUTSIDE(proto))
1938         outside = find_runcv(NULL);
1939       else {
1940         outside = CvOUTSIDE(proto);
1941         if ((CvCLONE(outside) && ! CvCLONED(outside))
1942             || !CvPADLIST(outside)
1943             || CvPADLIST(outside)->xpadl_id != protopadlist->xpadl_outid) {
1944             outside = find_runcv_where(
1945                 FIND_RUNCV_padid_eq, PTR2IV(protopadlist->xpadl_outid), NULL
1946             );
1947             /* outside could be null */
1948         }
1949       }
1950     }
1951     depth = outside ? CvDEPTH(outside) : 0;
1952     if (!depth)
1953         depth = 1;
1954 
1955     ENTER;
1956     SAVESPTR(PL_compcv);
1957     PL_compcv = cv;
1958     if (newcv) SAVEFREESV(cv); /* in case of fatal warnings */
1959 
1960     if (CvHASEVAL(cv))
1961         CvOUTSIDE(cv)	= MUTABLE_CV(SvREFCNT_inc_simple(outside));
1962 
1963     SAVESPTR(PL_comppad_name);
1964     PL_comppad_name = protopad_name;
1965     CvPADLIST_set(cv, pad_new(padnew_CLONE|padnew_SAVE));
1966     CvPADLIST(cv)->xpadl_id = protopadlist->xpadl_id;
1967 
1968     av_fill(PL_comppad, fpad);
1969 
1970     PL_curpad = AvARRAY(PL_comppad);
1971 
1972     outpad = outside && CvPADLIST(outside)
1973         ? AvARRAY(PadlistARRAY(CvPADLIST(outside))[depth])
1974         : NULL;
1975     if (outpad) CvPADLIST(cv)->xpadl_outid = CvPADLIST(outside)->xpadl_id;
1976 
1977     for (ix = fpad; ix > 0; ix--) {
1978         PADNAME* const namesv = (ix <= fname) ? pname[ix] : NULL;
1979         SV *sv = NULL;
1980         if (namesv && PadnameLEN(namesv)) { /* lexical */
1981           if (PadnameIsOUR(namesv)) { /* or maybe not so lexical */
1982                 NOOP;
1983           }
1984           else {
1985             if (PadnameOUTER(namesv)) {   /* lexical from outside? */
1986                 /* formats may have an inactive, or even undefined, parent;
1987                    but state vars are always available. */
1988                 if (!outpad || !(sv = outpad[PARENT_PAD_INDEX(namesv)])
1989                  || (  SvPADSTALE(sv) && !SvPAD_STATE(namesv)
1990                     && (!outside || !CvDEPTH(outside)))  ) {
1991                     S_unavailable(aTHX_ namesv);
1992                     sv = NULL;
1993                 }
1994                 else
1995                     SvREFCNT_inc_simple_void_NN(sv);
1996             }
1997             if (!sv) {
1998                 const char sigil = PadnamePV(namesv)[0];
1999                 if (sigil == '&')
2000                     /* If there are state subs, we need to clone them, too.
2001                        But they may need to close over variables we have
2002                        not cloned yet.  So we will have to do a second
2003                        pass.  Furthermore, there may be state subs clos-
2004                        ing over other state subs’ entries, so we have
2005                        to put a stub here and then clone into it on the
2006                        second pass. */
2007                     if (SvPAD_STATE(namesv) && !CvCLONED(ppad[ix])) {
2008                         assert(SvTYPE(ppad[ix]) == SVt_PVCV);
2009                         subclones ++;
2010                         if (CvOUTSIDE(ppad[ix]) != proto)
2011                              trouble = TRUE;
2012                         sv = newSV_type(SVt_PVCV);
2013                         CvLEXICAL_on(sv);
2014                     }
2015                     else if (PadnameLEN(namesv)>1 && !PadnameIsOUR(namesv))
2016                     {
2017                         /* my sub */
2018                         /* Just provide a stub, but name it.  It will be
2019                            upgraded to the real thing on scope entry. */
2020                         U32 hash;
2021                         PERL_HASH(hash, PadnamePV(namesv)+1,
2022                                   PadnameLEN(namesv) - 1);
2023                         sv = newSV_type(SVt_PVCV);
2024                         CvNAME_HEK_set(
2025                             sv,
2026                             share_hek(PadnamePV(namesv)+1,
2027                                       1 - PadnameLEN(namesv),
2028                                       hash)
2029                         );
2030                         CvLEXICAL_on(sv);
2031                     }
2032                     else sv = SvREFCNT_inc(ppad[ix]);
2033                 else if (sigil == '@')
2034                     sv = MUTABLE_SV(newAV());
2035                 else if (sigil == '%')
2036                     sv = MUTABLE_SV(newHV());
2037                 else
2038                     sv = newSV_type(SVt_NULL);
2039                 /* reset the 'assign only once' flag on each state var */
2040                 if (sigil != '&' && SvPAD_STATE(namesv))
2041                     SvPADSTALE_on(sv);
2042             }
2043           }
2044         }
2045         else if (namesv && PadnamePV(namesv)) {
2046             sv = SvREFCNT_inc_NN(ppad[ix]);
2047         }
2048         else {
2049             sv = newSV_type(SVt_NULL);
2050             SvPADTMP_on(sv);
2051         }
2052         PL_curpad[ix] = sv;
2053     }
2054 
2055     if (subclones)
2056     {
2057         if (trouble || cloned) {
2058             /* Uh-oh, we have trouble!  At least one of the state subs here
2059                has its CvOUTSIDE pointer pointing somewhere unexpected.  It
2060                could be pointing to another state protosub that we are
2061                about to clone.  So we have to track which sub clones come
2062                from which protosubs.  If the CvOUTSIDE pointer for a parti-
2063                cular sub points to something we have not cloned yet, we
2064                delay cloning it.  We must loop through the pad entries,
2065                until we get a full pass with no cloning.  If any uncloned
2066                subs remain (probably nested inside anonymous or ‘my’ subs),
2067                then they get cloned in a final pass.
2068              */
2069             bool cloned_in_this_pass;
2070             if (!cloned)
2071                 cloned = (HV *)newSV_type_mortal(SVt_PVHV);
2072             do {
2073                 cloned_in_this_pass = FALSE;
2074                 for (ix = fpad; ix > 0; ix--) {
2075                     PADNAME * const name =
2076                         (ix <= fname) ? pname[ix] : NULL;
2077                     if (name && name != &PL_padname_undef
2078                      && !PadnameOUTER(name) && PadnamePV(name)[0] == '&'
2079                      && PadnameIsSTATE(name) && !CvCLONED(PL_curpad[ix]))
2080                     {
2081                         CV * const protokey = CvOUTSIDE(ppad[ix]);
2082                         CV ** const cvp = protokey == proto
2083                             ? &cv
2084                             : (CV **)hv_fetch(cloned, (char *)&protokey,
2085                                               sizeof(CV *), 0);
2086                         if (cvp && *cvp) {
2087                             S_cv_clone(aTHX_ (CV *)ppad[ix],
2088                                              (CV *)PL_curpad[ix],
2089                                              *cvp, cloned);
2090                             (void)hv_store(cloned, (char *)&ppad[ix],
2091                                      sizeof(CV *),
2092                                      SvREFCNT_inc_simple_NN(PL_curpad[ix]),
2093                                      0);
2094                             subclones--;
2095                             cloned_in_this_pass = TRUE;
2096                         }
2097                     }
2098                 }
2099             } while (cloned_in_this_pass);
2100             if (subclones)
2101                 for (ix = fpad; ix > 0; ix--) {
2102                     PADNAME * const name =
2103                         (ix <= fname) ? pname[ix] : NULL;
2104                     if (name && name != &PL_padname_undef
2105                      && !PadnameOUTER(name) && PadnamePV(name)[0] == '&'
2106                      && PadnameIsSTATE(name) && !CvCLONED(PL_curpad[ix]))
2107                         S_cv_clone(aTHX_ (CV *)ppad[ix],
2108                                          (CV *)PL_curpad[ix],
2109                                          CvOUTSIDE(ppad[ix]), cloned);
2110                 }
2111         }
2112         else for (ix = fpad; ix > 0; ix--) {
2113             PADNAME * const name = (ix <= fname) ? pname[ix] : NULL;
2114             if (name && name != &PL_padname_undef && !PadnameOUTER(name)
2115              && PadnamePV(name)[0] == '&' && PadnameIsSTATE(name))
2116                 S_cv_clone(aTHX_ (CV *)ppad[ix], (CV *)PL_curpad[ix], cv,
2117                                  NULL);
2118         }
2119     }
2120 
2121     if (newcv) SvREFCNT_inc_simple_void_NN(cv);
2122     LEAVE;
2123 
2124     if (CvCONST(cv)) {
2125         /* Constant sub () { $x } closing over $x:
2126          * The prototype was marked as a candiate for const-ization,
2127          * so try to grab the current const value, and if successful,
2128          * turn into a const sub:
2129          */
2130         SV* const_sv;
2131         OP *o = CvSTART(cv);
2132         assert(newcv);
2133         for (; o; o = o->op_next)
2134             if (o->op_type == OP_PADSV)
2135                 break;
2136         ASSUME(o->op_type == OP_PADSV);
2137         const_sv = PAD_BASE_SV(CvPADLIST(cv), o->op_targ);
2138         /* the candidate should have 1 ref from this pad and 1 ref
2139          * from the parent */
2140         if (const_sv && SvREFCNT(const_sv) == 2) {
2141             const bool was_method = cBOOL(CvMETHOD(cv));
2142             if (outside) {
2143                 PADNAME * const pn =
2144                     PadlistNAMESARRAY(CvPADLIST(outside))
2145                         [PARENT_PAD_INDEX(PadlistNAMESARRAY(
2146                             CvPADLIST(cv))[o->op_targ])];
2147                 assert(PadnameOUTER(PadlistNAMESARRAY(CvPADLIST(cv))
2148                                         [o->op_targ]));
2149                 if (PadnameLVALUE(pn)) {
2150                     /* We have a lexical that is potentially modifiable
2151                        elsewhere, so making a constant will break clo-
2152                        sure behaviour.  If this is a ‘simple lexical
2153                        op tree’, i.e., sub(){$x}, emit a deprecation
2154                        warning, but continue to exhibit the old behav-
2155                        iour of making it a constant based on the ref-
2156                        count of the candidate variable.
2157 
2158                        A simple lexical op tree looks like this:
2159 
2160                          leavesub
2161                            lineseq
2162                              nextstate
2163                              padsv
2164                      */
2165                     if (OpSIBLING(
2166                          cUNOPx(cUNOPx(CvROOT(cv))->op_first)->op_first
2167                         ) == o
2168                      && !OpSIBLING(o))
2169                     {
2170                         Perl_croak(aTHX_
2171                             "Constants from lexical variables potentially modified "
2172                             "elsewhere are no longer permitted");
2173                     }
2174                     else
2175                         goto constoff;
2176                 }
2177             }
2178             SvREFCNT_inc_simple_void_NN(const_sv);
2179             /* If the lexical is not used elsewhere, it is safe to turn on
2180                SvPADTMP, since it is only when it is used in lvalue con-
2181                text that the difference is observable.  */
2182             SvREADONLY_on(const_sv);
2183             SvPADTMP_on(const_sv);
2184             SvREFCNT_dec_NN(cv);
2185             cv = newCONSTSUB(CvSTASH(proto), NULL, const_sv);
2186             if (was_method)
2187                 CvMETHOD_on(cv);
2188         }
2189         else {
2190           constoff:
2191             CvCONST_off(cv);
2192         }
2193     }
2194 
2195     return cv;
2196 }
2197 
2198 static CV *
2199 S_cv_clone(pTHX_ CV *proto, CV *cv, CV *outside, HV *cloned)
2200 {
2201     const bool newcv = !cv;
2202 
2203     assert(!CvUNIQUE(proto));
2204 
2205     if (!cv) cv = MUTABLE_CV(newSV_type(SvTYPE(proto)));
2206     CvFLAGS(cv) = CvFLAGS(proto) & ~(CVf_CLONE|CVf_WEAKOUTSIDE|CVf_CVGV_RC
2207                                     |CVf_SLABBED);
2208     CvCLONED_on(cv);
2209 
2210     CvFILE(cv)		= CvDYNFILE(proto) ? savepv(CvFILE(proto))
2211                                            : CvFILE(proto);
2212     if (CvNAMED(proto))
2213          CvNAME_HEK_set(cv, share_hek_hek(CvNAME_HEK(proto)));
2214     else CvGV_set(cv,CvGV(proto));
2215     CvSTASH_set(cv, CvSTASH(proto));
2216 
2217     /* It is unlikely that proto is an xsub, but it could happen; e.g. if a
2218      * module has performed a lexical sub import trick on an xsub. This
2219      * happens with builtin::import, for example
2220      */
2221     if (UNLIKELY(CvISXSUB(proto))) {
2222         CvXSUB(cv)    = CvXSUB(proto);
2223         CvXSUBANY(cv) = CvXSUBANY(proto);
2224     }
2225     else {
2226         OP_REFCNT_LOCK;
2227         CvROOT(cv) = OpREFCNT_inc(CvROOT(proto));
2228         OP_REFCNT_UNLOCK;
2229         CvSTART(cv) = CvSTART(proto);
2230         CvOUTSIDE_SEQ(cv) = CvOUTSIDE_SEQ(proto);
2231     }
2232 
2233     if (SvPOK(proto)) {
2234         sv_setpvn(MUTABLE_SV(cv), SvPVX_const(proto), SvCUR(proto));
2235         if (SvUTF8(proto))
2236            SvUTF8_on(MUTABLE_SV(cv));
2237     }
2238     if (SvMAGIC(proto))
2239         mg_copy((SV *)proto, (SV *)cv, 0, 0);
2240 
2241     if (!CvISXSUB(proto) && CvPADLIST(proto))
2242         cv = S_cv_clone_pad(aTHX_ proto, cv, outside, cloned, newcv);
2243 
2244     DEBUG_Xv(
2245         PerlIO_printf(Perl_debug_log, "\nPad CV clone\n");
2246         if (CvOUTSIDE(cv)) cv_dump(CvOUTSIDE(cv), "Outside");
2247         cv_dump(proto,	 "Proto");
2248         cv_dump(cv,	 "To");
2249     );
2250 
2251     return cv;
2252 }
2253 
2254 CV *
2255 Perl_cv_clone(pTHX_ CV *proto)
2256 {
2257     PERL_ARGS_ASSERT_CV_CLONE;
2258 
2259     if (!CvPADLIST(proto)) Perl_croak(aTHX_ "panic: no pad in cv_clone");
2260     return S_cv_clone(aTHX_ proto, NULL, NULL, NULL);
2261 }
2262 
2263 /* Called only by pp_clonecv */
2264 CV *
2265 Perl_cv_clone_into(pTHX_ CV *proto, CV *target)
2266 {
2267     PERL_ARGS_ASSERT_CV_CLONE_INTO;
2268     cv_undef(target);
2269     return S_cv_clone(aTHX_ proto, target, NULL, NULL);
2270 }
2271 
2272 /*
2273 =for apidoc cv_name
2274 
2275 Returns an SV containing the name of the CV, mainly for use in error
2276 reporting.  The CV may actually be a GV instead, in which case the returned
2277 SV holds the GV's name.  Anything other than a GV or CV is treated as a
2278 string already holding the sub name, but this could change in the future.
2279 
2280 An SV may be passed as a second argument.  If so, the name will be assigned
2281 to it and it will be returned.  Otherwise the returned SV will be a new
2282 mortal.
2283 
2284 If C<flags> has the C<CV_NAME_NOTQUAL> bit set, then the package name will not be
2285 included.  If the first argument is neither a CV nor a GV, this flag is
2286 ignored (subject to change).
2287 
2288 =for apidoc Amnh||CV_NAME_NOTQUAL
2289 
2290 =cut
2291 */
2292 
2293 SV *
2294 Perl_cv_name(pTHX_ CV *cv, SV *sv, U32 flags)
2295 {
2296     PERL_ARGS_ASSERT_CV_NAME;
2297     if (!isGV_with_GP(cv) && SvTYPE(cv) != SVt_PVCV) {
2298         if (sv) sv_setsv(sv,(SV *)cv);
2299         return sv ? (sv) : (SV *)cv;
2300     }
2301     {
2302         SV * const retsv = sv ? (sv) : sv_newmortal();
2303         if (SvTYPE(cv) == SVt_PVCV) {
2304             if (CvNAMED(cv)) {
2305                 if (CvLEXICAL(cv) || flags & CV_NAME_NOTQUAL)
2306                     sv_sethek(retsv, CvNAME_HEK(cv));
2307                 else {
2308                     if (CvSTASH(cv) && HvNAME_HEK(CvSTASH(cv)))
2309                         sv_sethek(retsv, HvNAME_HEK(CvSTASH(cv)));
2310                     else
2311                         sv_setpvs(retsv, "__ANON__");
2312                     sv_catpvs(retsv, "::");
2313                     sv_cathek(retsv, CvNAME_HEK(cv));
2314                 }
2315             }
2316             else if (CvLEXICAL(cv) || flags & CV_NAME_NOTQUAL)
2317                 sv_sethek(retsv, GvNAME_HEK(GvEGV(CvGV(cv))));
2318             else gv_efullname3(retsv, CvGV(cv), NULL);
2319         }
2320         else if (flags & CV_NAME_NOTQUAL) sv_sethek(retsv, GvNAME_HEK(cv));
2321         else gv_efullname3(retsv,(GV *)cv,NULL);
2322         return retsv;
2323     }
2324 }
2325 
2326 /*
2327 =for apidoc pad_fixup_inner_anons
2328 
2329 For any anon CVs in the pad, change C<CvOUTSIDE> of that CV from
2330 C<old_cv> to C<new_cv> if necessary.  Needed when a newly-compiled CV has to be
2331 moved to a pre-existing CV struct.
2332 
2333 =cut
2334 */
2335 
2336 void
2337 Perl_pad_fixup_inner_anons(pTHX_ PADLIST *padlist, CV *old_cv, CV *new_cv)
2338 {
2339     PADOFFSET ix;
2340     PADNAMELIST * const comppad_name = PadlistNAMES(padlist);
2341     AV * const comppad = PadlistARRAY(padlist)[1];
2342     PADNAME ** const namepad = PadnamelistARRAY(comppad_name);
2343     SV ** const curpad = AvARRAY(comppad);
2344 
2345     PERL_ARGS_ASSERT_PAD_FIXUP_INNER_ANONS;
2346     PERL_UNUSED_ARG(old_cv);
2347 
2348     for (ix = PadnamelistMAX(comppad_name); ix > 0; ix--) {
2349         const PADNAME *name = namepad[ix];
2350         if (name && name != &PL_padname_undef && !PadnameIsOUR(name)
2351             && *PadnamePV(name) == '&')
2352         {
2353           CV *innercv = MUTABLE_CV(curpad[ix]);
2354           if (UNLIKELY(PadnameOUTER(name))) {
2355             CV *cv = new_cv;
2356             PADNAME **names = namepad;
2357             PADOFFSET i = ix;
2358             while (PadnameOUTER(name)) {
2359                 assert(SvTYPE(cv) == SVt_PVCV);
2360                 cv = CvOUTSIDE(cv);
2361                 names = PadlistNAMESARRAY(CvPADLIST(cv));
2362                 i = PARENT_PAD_INDEX(name);
2363                 name = names[i];
2364             }
2365             innercv = (CV *)PadARRAY(PadlistARRAY(CvPADLIST(cv))[1])[i];
2366           }
2367           if (SvTYPE(innercv) == SVt_PVCV) {
2368             /* XXX 0afba48f added code here to check for a proto CV
2369                    attached to the pad entry by magic.  But shortly there-
2370                    after 81df9f6f95 moved the magic to the pad name.  The
2371                    code here was never updated, so it wasn’t doing anything
2372                    and got deleted when PADNAME became a distinct type.  Is
2373                    there any bug as a result?  */
2374             if (CvOUTSIDE(innercv) == old_cv) {
2375                 if (!CvWEAKOUTSIDE(innercv)) {
2376                     SvREFCNT_dec(old_cv);
2377                     SvREFCNT_inc_simple_void_NN(new_cv);
2378                 }
2379                 CvOUTSIDE(innercv) = new_cv;
2380             }
2381           }
2382           else { /* format reference */
2383             SV * const rv = curpad[ix];
2384             CV *innercv;
2385             if (!SvOK(rv)) continue;
2386             assert(SvROK(rv));
2387             assert(SvWEAKREF(rv));
2388             innercv = (CV *)SvRV(rv);
2389             assert(!CvWEAKOUTSIDE(innercv));
2390             assert(CvOUTSIDE(innercv) == old_cv);
2391             SvREFCNT_dec(CvOUTSIDE(innercv));
2392             CvOUTSIDE(innercv) = (CV *)SvREFCNT_inc_simple_NN(new_cv);
2393           }
2394         }
2395     }
2396 }
2397 
2398 /*
2399 =for apidoc pad_push
2400 
2401 Push a new pad frame onto the padlist, unless there's already a pad at
2402 this depth, in which case don't bother creating a new one.  Then give
2403 the new pad an C<@_> in slot zero.
2404 
2405 =cut
2406 */
2407 
2408 void
2409 Perl_pad_push(pTHX_ PADLIST *padlist, int depth)
2410 {
2411     PERL_ARGS_ASSERT_PAD_PUSH;
2412 
2413     if (depth > PadlistMAX(padlist) || !PadlistARRAY(padlist)[depth]) {
2414         PAD** const svp = PadlistARRAY(padlist);
2415         AV* const newpad = newAV();
2416         SV** const oldpad = AvARRAY(svp[depth-1]);
2417         PADOFFSET ix = AvFILLp((const AV *)svp[1]);
2418         const PADOFFSET names_fill = PadnamelistMAX((PADNAMELIST *)svp[0]);
2419         PADNAME ** const names = PadnamelistARRAY((PADNAMELIST *)svp[0]);
2420         AV *av;
2421 
2422         Newxz( AvALLOC(newpad), ix + 1, SV *);
2423         AvARRAY(newpad) = AvALLOC(newpad);
2424         AvMAX(newpad) = AvFILLp(newpad) = ix;
2425 
2426         for ( ;ix > 0; ix--) {
2427             SV *sv;
2428             if (names_fill >= ix && PadnameLEN(names[ix])) {
2429                 const char sigil = PadnamePV(names[ix])[0];
2430                 if (PadnameOUTER(names[ix])
2431                         || PadnameIsSTATE(names[ix])
2432                         || sigil == '&')
2433                 {
2434                     /* outer lexical or anon code */
2435                     sv = SvREFCNT_inc(oldpad[ix]);
2436                 }
2437                 else {		/* our own lexical */
2438                     if (sigil == '@')
2439                         sv = MUTABLE_SV(newAV());
2440                     else if (sigil == '%')
2441                         sv = MUTABLE_SV(newHV());
2442                     else
2443                         sv = newSV_type(SVt_NULL);
2444                 }
2445             }
2446             else if (PadnamePV(names[ix])) {
2447                 sv = SvREFCNT_inc_NN(oldpad[ix]);
2448             }
2449             else {
2450                 /* save temporaries on recursion? */
2451                 sv = newSV_type(SVt_NULL);
2452                 SvPADTMP_on(sv);
2453             }
2454             AvARRAY(newpad)[ix] = sv;
2455         }
2456         av = newAV();
2457         AvARRAY(newpad)[0] = MUTABLE_SV(av);
2458         AvREIFY_only(av);
2459 
2460         padlist_store(padlist, depth, newpad);
2461     }
2462 }
2463 
2464 #if defined(USE_ITHREADS)
2465 
2466 #  define av_dup_inc(s,t)	MUTABLE_AV(sv_dup_inc((const SV *)s,t))
2467 
2468 /*
2469 =for apidoc padlist_dup
2470 
2471 Duplicates a pad.
2472 
2473 =cut
2474 */
2475 
2476 PADLIST *
2477 Perl_padlist_dup(pTHX_ PADLIST *srcpad, CLONE_PARAMS *param)
2478 {
2479     PADLIST *dstpad;
2480     bool cloneall;
2481     PADOFFSET max;
2482 
2483     PERL_ARGS_ASSERT_PADLIST_DUP;
2484 
2485     cloneall = cBOOL(param->flags & CLONEf_COPY_STACKS);
2486     assert (SvREFCNT(PadlistARRAY(srcpad)[1]) == 1);
2487 
2488     max = cloneall ? PadlistMAX(srcpad) : 1;
2489 
2490     Newx(dstpad, 1, PADLIST);
2491     ptr_table_store(PL_ptr_table, srcpad, dstpad);
2492     PadlistMAX(dstpad) = max;
2493     Newx(PadlistARRAY(dstpad), max + 1, PAD *);
2494 
2495     PadlistARRAY(dstpad)[0] = (PAD *)
2496             padnamelist_dup(PadlistNAMES(srcpad), param);
2497     PadnamelistREFCNT(PadlistNAMES(dstpad))++;
2498     if (cloneall) {
2499         PADOFFSET depth;
2500         for (depth = 1; depth <= max; ++depth)
2501             PadlistARRAY(dstpad)[depth] =
2502                 av_dup_inc(PadlistARRAY(srcpad)[depth], param);
2503     } else {
2504         /* CvDEPTH() on our subroutine will be set to 0, so there's no need
2505            to build anything other than the first level of pads.  */
2506         PADOFFSET ix = AvFILLp(PadlistARRAY(srcpad)[1]);
2507         AV *pad1;
2508         const PADOFFSET names_fill = PadnamelistMAX(PadlistNAMES(srcpad));
2509         const PAD *const srcpad1 = PadlistARRAY(srcpad)[1];
2510         SV **oldpad = AvARRAY(srcpad1);
2511         PADNAME ** const names = PadnamelistARRAY(PadlistNAMES(dstpad));
2512         SV **pad1a;
2513         AV *args;
2514 
2515         pad1 = newAV();
2516 
2517         av_extend(pad1, ix);
2518         PadlistARRAY(dstpad)[1] = pad1;
2519         pad1a = AvARRAY(pad1);
2520 
2521         if (ix > -1) {
2522             AvFILLp(pad1) = ix;
2523 
2524             for ( ;ix > 0; ix--) {
2525                 if (!oldpad[ix]) {
2526                     pad1a[ix] = NULL;
2527                 } else if (names_fill >= ix && names[ix] &&
2528                            PadnameLEN(names[ix])) {
2529                     const char sigil = PadnamePV(names[ix])[0];
2530                     if (PadnameOUTER(names[ix])
2531                         || PadnameIsSTATE(names[ix])
2532                         || sigil == '&')
2533                         {
2534                             /* outer lexical or anon code */
2535                             pad1a[ix] = sv_dup_inc(oldpad[ix], param);
2536                         }
2537                     else {		/* our own lexical */
2538                         if(SvPADSTALE(oldpad[ix]) && SvREFCNT(oldpad[ix]) > 1) {
2539                             /* This is a work around for how the current
2540                                implementation of ?{ } blocks in regexps
2541                                interacts with lexicals.  */
2542                             pad1a[ix] = sv_dup_inc(oldpad[ix], param);
2543                         } else {
2544                             SV *sv;
2545 
2546                             if (sigil == '@')
2547                                 sv = MUTABLE_SV(newAV());
2548                             else if (sigil == '%')
2549                                 sv = MUTABLE_SV(newHV());
2550                             else
2551                                 sv = newSV_type(SVt_NULL);
2552                             pad1a[ix] = sv;
2553                         }
2554                     }
2555                 }
2556                 else if ((  names_fill >= ix && names[ix]
2557                          && PadnamePV(names[ix])  )) {
2558                     pad1a[ix] = sv_dup_inc(oldpad[ix], param);
2559                 }
2560                 else {
2561                     /* save temporaries on recursion? */
2562                     SV * const sv = newSV_type(SVt_NULL);
2563                     pad1a[ix] = sv;
2564 
2565                     /* SvREFCNT(oldpad[ix]) != 1 for some code in threads.xs
2566                        FIXTHAT before merging this branch.
2567                        (And I know how to) */
2568                     if (SvPADTMP(oldpad[ix]))
2569                         SvPADTMP_on(sv);
2570                 }
2571             }
2572 
2573             if (oldpad[0]) {
2574                 args = newAV();			/* Will be @_ */
2575                 AvREIFY_only(args);
2576                 pad1a[0] = (SV *)args;
2577             }
2578         }
2579     }
2580 
2581     return dstpad;
2582 }
2583 
2584 #endif /* USE_ITHREADS */
2585 
2586 PAD **
2587 Perl_padlist_store(pTHX_ PADLIST *padlist, I32 key, PAD *val)
2588 {
2589     PAD **ary;
2590     SSize_t const oldmax = PadlistMAX(padlist);
2591 
2592     PERL_ARGS_ASSERT_PADLIST_STORE;
2593 
2594     assert(key >= 0);
2595 
2596     if (key > PadlistMAX(padlist)) {
2597         av_extend_guts(NULL,key,&PadlistMAX(padlist),
2598                        (SV ***)&PadlistARRAY(padlist),
2599                        (SV ***)&PadlistARRAY(padlist));
2600         Zero(PadlistARRAY(padlist)+oldmax+1, PadlistMAX(padlist)-oldmax,
2601              PAD *);
2602     }
2603     ary = PadlistARRAY(padlist);
2604     SvREFCNT_dec(ary[key]);
2605     ary[key] = val;
2606     return &ary[key];
2607 }
2608 
2609 /*
2610 =for apidoc newPADNAMELIST
2611 
2612 Creates a new pad name list.  C<max> is the highest index for which space
2613 is allocated.
2614 
2615 =cut
2616 */
2617 
2618 PADNAMELIST *
2619 Perl_newPADNAMELIST(size_t max)
2620 {
2621     PADNAMELIST *pnl;
2622     Newx(pnl, 1, PADNAMELIST);
2623     Newxz(PadnamelistARRAY(pnl), max+1, PADNAME *);
2624     PadnamelistMAX(pnl) = -1;
2625     PadnamelistREFCNT(pnl) = 1;
2626     PadnamelistMAXNAMED(pnl) = 0;
2627     pnl->xpadnl_max = max;
2628     return pnl;
2629 }
2630 
2631 /*
2632 =for apidoc padnamelist_store
2633 
2634 Stores the pad name (which may be null) at the given index, freeing any
2635 existing pad name in that slot.
2636 
2637 =cut
2638 */
2639 
2640 PADNAME **
2641 Perl_padnamelist_store(pTHX_ PADNAMELIST *pnl, SSize_t key, PADNAME *val)
2642 {
2643     PADNAME **ary;
2644 
2645     PERL_ARGS_ASSERT_PADNAMELIST_STORE;
2646 
2647     assert(key >= 0);
2648 
2649     if (key > pnl->xpadnl_max)
2650         av_extend_guts(NULL,key,&pnl->xpadnl_max,
2651                        (SV ***)&PadnamelistARRAY(pnl),
2652                        (SV ***)&PadnamelistARRAY(pnl));
2653     if (PadnamelistMAX(pnl) < key) {
2654         Zero(PadnamelistARRAY(pnl)+PadnamelistMAX(pnl)+1,
2655              key-PadnamelistMAX(pnl), PADNAME *);
2656         PadnamelistMAX(pnl) = key;
2657     }
2658     ary = PadnamelistARRAY(pnl);
2659     if (ary[key])
2660         PadnameREFCNT_dec(ary[key]);
2661     ary[key] = val;
2662     return &ary[key];
2663 }
2664 
2665 /*
2666 =for apidoc padnamelist_fetch
2667 
2668 Fetches the pad name from the given index.
2669 
2670 =cut
2671 */
2672 
2673 PADNAME *
2674 Perl_padnamelist_fetch(PADNAMELIST *pnl, SSize_t key)
2675 {
2676     PERL_ARGS_ASSERT_PADNAMELIST_FETCH;
2677     ASSUME(key >= 0);
2678 
2679     return key > PadnamelistMAX(pnl) ? NULL : PadnamelistARRAY(pnl)[key];
2680 }
2681 
2682 void
2683 Perl_padnamelist_free(pTHX_ PADNAMELIST *pnl)
2684 {
2685     PERL_ARGS_ASSERT_PADNAMELIST_FREE;
2686     if (!--PadnamelistREFCNT(pnl)) {
2687         while(PadnamelistMAX(pnl) >= 0)
2688         {
2689             PADNAME * const pn =
2690                 PadnamelistARRAY(pnl)[PadnamelistMAX(pnl)--];
2691             if (pn)
2692                 PadnameREFCNT_dec(pn);
2693         }
2694         Safefree(PadnamelistARRAY(pnl));
2695         Safefree(pnl);
2696     }
2697 }
2698 
2699 #if defined(USE_ITHREADS)
2700 
2701 /*
2702 =for apidoc padnamelist_dup
2703 
2704 Duplicates a pad name list.
2705 
2706 =cut
2707 */
2708 
2709 PADNAMELIST *
2710 Perl_padnamelist_dup(pTHX_ PADNAMELIST *srcpad, CLONE_PARAMS *param)
2711 {
2712     PADNAMELIST *dstpad;
2713     SSize_t max = PadnamelistMAX(srcpad);
2714 
2715     PERL_ARGS_ASSERT_PADNAMELIST_DUP;
2716 
2717     /* look for it in the table first */
2718     dstpad = (PADNAMELIST *)ptr_table_fetch(PL_ptr_table, srcpad);
2719     if (dstpad)
2720         return dstpad;
2721 
2722     dstpad = newPADNAMELIST(max);
2723     PadnamelistREFCNT(dstpad) = 0; /* The caller will increment it.  */
2724     PadnamelistMAXNAMED(dstpad) = PadnamelistMAXNAMED(srcpad);
2725     PadnamelistMAX(dstpad) = max;
2726 
2727     ptr_table_store(PL_ptr_table, srcpad, dstpad);
2728     for (; max >= 0; max--)
2729       if (PadnamelistARRAY(srcpad)[max]) {
2730         PadnamelistARRAY(dstpad)[max] =
2731             padname_dup(PadnamelistARRAY(srcpad)[max], param);
2732         PadnameREFCNT(PadnamelistARRAY(dstpad)[max])++;
2733       }
2734 
2735     return dstpad;
2736 }
2737 
2738 #endif /* USE_ITHREADS */
2739 
2740 /*
2741 =for apidoc newPADNAMEpvn
2742 
2743 Constructs and returns a new pad name.  C<s> must be a UTF-8 string.  Do not
2744 use this for pad names that point to outer lexicals.  See
2745 C<L</newPADNAMEouter>>.
2746 
2747 =cut
2748 */
2749 
2750 PADNAME *
2751 Perl_newPADNAMEpvn(const char *s, STRLEN len)
2752 {
2753     struct padname_with_str *alloc;
2754     char *alloc2; /* for Newxz */
2755     PADNAME *pn;
2756     PERL_ARGS_ASSERT_NEWPADNAMEPVN;
2757     Newxz(alloc2,
2758           STRUCT_OFFSET(struct padname_with_str, xpadn_str[0]) + len + 1,
2759           char);
2760     alloc = (struct padname_with_str *)alloc2;
2761     pn = (PADNAME *)alloc;
2762     PadnameREFCNT(pn) = 1;
2763     PadnamePV(pn) = alloc->xpadn_str;
2764     Copy(s, PadnamePV(pn), len, char);
2765     *(PadnamePV(pn) + len) = '\0';
2766     PadnameLEN(pn) = len;
2767     return pn;
2768 }
2769 
2770 /*
2771 =for apidoc newPADNAMEouter
2772 
2773 Constructs and returns a new pad name.  Only use this function for names
2774 that refer to outer lexicals.  (See also L</newPADNAMEpvn>.)  C<outer> is
2775 the outer pad name that this one mirrors.  The returned pad name has the
2776 C<PADNAMEt_OUTER> flag already set.
2777 
2778 =for apidoc Amnh||PADNAMEt_OUTER
2779 
2780 =cut
2781 */
2782 
2783 PADNAME *
2784 Perl_newPADNAMEouter(PADNAME *outer)
2785 {
2786     PADNAME *pn;
2787     PERL_ARGS_ASSERT_NEWPADNAMEOUTER;
2788     Newxz(pn, 1, PADNAME);
2789     PadnameREFCNT(pn) = 1;
2790     PadnamePV(pn) = PadnamePV(outer);
2791     /* Not PadnameREFCNT(outer), because ‘outer’ may itself close over
2792        another entry.  The original pad name owns the buffer.  */
2793     PadnameREFCNT(PADNAME_FROM_PV(PadnamePV(outer)))++;
2794     PadnameFLAGS(pn) = PADNAMEt_OUTER;
2795     PadnameLEN(pn) = PadnameLEN(outer);
2796     return pn;
2797 }
2798 
2799 void
2800 Perl_padname_free(pTHX_ PADNAME *pn)
2801 {
2802     PERL_ARGS_ASSERT_PADNAME_FREE;
2803     if (!--PadnameREFCNT(pn)) {
2804         if (UNLIKELY(pn == &PL_padname_undef || pn == &PL_padname_const)) {
2805             PadnameREFCNT(pn) = SvREFCNT_IMMORTAL;
2806             return;
2807         }
2808         SvREFCNT_dec(PadnameTYPE(pn)); /* Takes care of protocv, too.  */
2809         SvREFCNT_dec(PadnameOURSTASH(pn));
2810         if (PadnameOUTER(pn))
2811             PadnameREFCNT_dec(PADNAME_FROM_PV(PadnamePV(pn)));
2812         Safefree(pn);
2813     }
2814 }
2815 
2816 #if defined(USE_ITHREADS)
2817 
2818 /*
2819 =for apidoc padname_dup
2820 
2821 Duplicates a pad name.
2822 
2823 =cut
2824 */
2825 
2826 PADNAME *
2827 Perl_padname_dup(pTHX_ PADNAME *src, CLONE_PARAMS *param)
2828 {
2829     PADNAME *dst;
2830 
2831     PERL_ARGS_ASSERT_PADNAME_DUP;
2832 
2833     /* look for it in the table first */
2834     dst = (PADNAME *)ptr_table_fetch(PL_ptr_table, src);
2835     if (dst)
2836         return dst;
2837 
2838     if (!PadnamePV(src)) {
2839         dst = &PL_padname_undef;
2840         ptr_table_store(PL_ptr_table, src, dst);
2841         return dst;
2842     }
2843 
2844     dst = PadnameOUTER(src)
2845      ? newPADNAMEouter(padname_dup(PADNAME_FROM_PV(PadnamePV(src)), param))
2846      : newPADNAMEpvn(PadnamePV(src), PadnameLEN(src));
2847     ptr_table_store(PL_ptr_table, src, dst);
2848     PadnameLEN(dst) = PadnameLEN(src);
2849     PadnameFLAGS(dst) = PadnameFLAGS(src);
2850     PadnameREFCNT(dst) = 0; /* The caller will increment it.  */
2851     PadnameTYPE   (dst) = (HV *)sv_dup_inc((SV *)PadnameTYPE(src), param);
2852     PadnameOURSTASH(dst) = (HV *)sv_dup_inc((SV *)PadnameOURSTASH(src),
2853                                             param);
2854     dst->xpadn_low  = src->xpadn_low;
2855     dst->xpadn_high = src->xpadn_high;
2856     dst->xpadn_gen  = src->xpadn_gen;
2857     return dst;
2858 }
2859 
2860 #endif /* USE_ITHREADS */
2861 
2862 /*
2863  * ex: set ts=8 sts=4 sw=4 et:
2864  */
2865