xref: /openbsd-src/gnu/usr.bin/perl/scope.c (revision a28daedfc357b214be5c701aa8ba8adb29a7f1c2)
1 /*    scope.c
2  *
3  *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
4  *    2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 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 /*
12  * "For the fashion of Minas Tirith was such that it was built on seven
13  * levels..."
14  */
15 
16 /* This file contains functions to manipulate several of Perl's stacks;
17  * in particular it contains code to push various types of things onto
18  * the savestack, then to pop them off and perform the correct restorative
19  * action for each one. This corresponds to the cleanup Perl does at
20  * each scope exit.
21  */
22 
23 #include "EXTERN.h"
24 #define PERL_IN_SCOPE_C
25 #include "perl.h"
26 
27 SV**
28 Perl_stack_grow(pTHX_ SV **sp, SV **p, int n)
29 {
30     dVAR;
31     PL_stack_sp = sp;
32 #ifndef STRESS_REALLOC
33     av_extend(PL_curstack, (p - PL_stack_base) + (n) + 128);
34 #else
35     av_extend(PL_curstack, (p - PL_stack_base) + (n) + 1);
36 #endif
37     return PL_stack_sp;
38 }
39 
40 #ifndef STRESS_REALLOC
41 #define GROW(old) ((old) * 3 / 2)
42 #else
43 #define GROW(old) ((old) + 1)
44 #endif
45 
46 PERL_SI *
47 Perl_new_stackinfo(pTHX_ I32 stitems, I32 cxitems)
48 {
49     dVAR;
50     PERL_SI *si;
51     Newx(si, 1, PERL_SI);
52     si->si_stack = newAV();
53     AvREAL_off(si->si_stack);
54     av_extend(si->si_stack, stitems > 0 ? stitems-1 : 0);
55     AvALLOC(si->si_stack)[0] = &PL_sv_undef;
56     AvFILLp(si->si_stack) = 0;
57     si->si_prev = 0;
58     si->si_next = 0;
59     si->si_cxmax = cxitems - 1;
60     si->si_cxix = -1;
61     si->si_type = PERLSI_UNDEF;
62     Newx(si->si_cxstack, cxitems, PERL_CONTEXT);
63     /* Without any kind of initialising PUSHSUBST()
64      * in pp_subst() will read uninitialised heap. */
65     PoisonNew(si->si_cxstack, cxitems, PERL_CONTEXT);
66     return si;
67 }
68 
69 I32
70 Perl_cxinc(pTHX)
71 {
72     dVAR;
73     const IV old_max = cxstack_max;
74     cxstack_max = GROW(cxstack_max);
75     Renew(cxstack, cxstack_max + 1, PERL_CONTEXT);	/* XXX should fix CXINC macro */
76     /* Without any kind of initialising deep enough recursion
77      * will end up reading uninitialised PERL_CONTEXTs. */
78     PoisonNew(cxstack + old_max + 1, cxstack_max - old_max, PERL_CONTEXT);
79     return cxstack_ix + 1;
80 }
81 
82 void
83 Perl_push_scope(pTHX)
84 {
85     dVAR;
86     if (PL_scopestack_ix == PL_scopestack_max) {
87 	PL_scopestack_max = GROW(PL_scopestack_max);
88 	Renew(PL_scopestack, PL_scopestack_max, I32);
89     }
90     PL_scopestack[PL_scopestack_ix++] = PL_savestack_ix;
91 
92 }
93 
94 void
95 Perl_pop_scope(pTHX)
96 {
97     dVAR;
98     const I32 oldsave = PL_scopestack[--PL_scopestack_ix];
99     LEAVE_SCOPE(oldsave);
100 }
101 
102 void
103 Perl_markstack_grow(pTHX)
104 {
105     dVAR;
106     const I32 oldmax = PL_markstack_max - PL_markstack;
107     const I32 newmax = GROW(oldmax);
108 
109     Renew(PL_markstack, newmax, I32);
110     PL_markstack_ptr = PL_markstack + oldmax;
111     PL_markstack_max = PL_markstack + newmax;
112 }
113 
114 void
115 Perl_savestack_grow(pTHX)
116 {
117     dVAR;
118     PL_savestack_max = GROW(PL_savestack_max) + 4;
119     Renew(PL_savestack, PL_savestack_max, ANY);
120 }
121 
122 void
123 Perl_savestack_grow_cnt(pTHX_ I32 need)
124 {
125     dVAR;
126     PL_savestack_max = PL_savestack_ix + need;
127     Renew(PL_savestack, PL_savestack_max, ANY);
128 }
129 
130 #undef GROW
131 
132 void
133 Perl_tmps_grow(pTHX_ I32 n)
134 {
135     dVAR;
136 #ifndef STRESS_REALLOC
137     if (n < 128)
138 	n = (PL_tmps_max < 512) ? 128 : 512;
139 #endif
140     PL_tmps_max = PL_tmps_ix + n + 1;
141     Renew(PL_tmps_stack, PL_tmps_max, SV*);
142 }
143 
144 
145 void
146 Perl_free_tmps(pTHX)
147 {
148     dVAR;
149     /* XXX should tmps_floor live in cxstack? */
150     const I32 myfloor = PL_tmps_floor;
151     while (PL_tmps_ix > myfloor) {      /* clean up after last statement */
152 	SV* const sv = PL_tmps_stack[PL_tmps_ix];
153 	PL_tmps_stack[PL_tmps_ix--] = NULL;
154 	if (sv && sv != &PL_sv_undef) {
155 	    SvTEMP_off(sv);
156 	    SvREFCNT_dec(sv);		/* note, can modify tmps_ix!!! */
157 	}
158     }
159 }
160 
161 STATIC SV *
162 S_save_scalar_at(pTHX_ SV **sptr)
163 {
164     dVAR;
165     SV * const osv = *sptr;
166     register SV * const sv = *sptr = newSV(0);
167 
168     if (SvTYPE(osv) >= SVt_PVMG && SvMAGIC(osv) && SvTYPE(osv) != SVt_PVGV) {
169 	if (SvGMAGICAL(osv)) {
170 	    const bool oldtainted = PL_tainted;
171 	    SvFLAGS(osv) |= (SvFLAGS(osv) &
172 	       (SVp_IOK|SVp_NOK|SVp_POK)) >> PRIVSHIFT;
173 	    PL_tainted = oldtainted;
174 	}
175 	mg_localize(osv, sv);
176     }
177     return sv;
178 }
179 
180 SV *
181 Perl_save_scalar(pTHX_ GV *gv)
182 {
183     dVAR;
184     SV ** const sptr = &GvSVn(gv);
185     PL_localizing = 1;
186     SvGETMAGIC(*sptr);
187     PL_localizing = 0;
188     SSCHECK(3);
189     SSPUSHPTR(SvREFCNT_inc_simple(gv));
190     SSPUSHPTR(SvREFCNT_inc(*sptr));
191     SSPUSHINT(SAVEt_SV);
192     return save_scalar_at(sptr);
193 }
194 
195 /* Like save_sptr(), but also SvREFCNT_dec()s the new value.  Can be used to
196  * restore a global SV to its prior contents, freeing new value. */
197 void
198 Perl_save_generic_svref(pTHX_ SV **sptr)
199 {
200     dVAR;
201     SSCHECK(3);
202     SSPUSHPTR(sptr);
203     SSPUSHPTR(SvREFCNT_inc(*sptr));
204     SSPUSHINT(SAVEt_GENERIC_SVREF);
205 }
206 
207 /* Like save_pptr(), but also Safefree()s the new value if it is different
208  * from the old one.  Can be used to restore a global char* to its prior
209  * contents, freeing new value. */
210 void
211 Perl_save_generic_pvref(pTHX_ char **str)
212 {
213     dVAR;
214     SSCHECK(3);
215     SSPUSHPTR(*str);
216     SSPUSHPTR(str);
217     SSPUSHINT(SAVEt_GENERIC_PVREF);
218 }
219 
220 /* Like save_generic_pvref(), but uses PerlMemShared_free() rather than Safefree().
221  * Can be used to restore a shared global char* to its prior
222  * contents, freeing new value. */
223 void
224 Perl_save_shared_pvref(pTHX_ char **str)
225 {
226     dVAR;
227     SSCHECK(3);
228     SSPUSHPTR(str);
229     SSPUSHPTR(*str);
230     SSPUSHINT(SAVEt_SHARED_PVREF);
231 }
232 
233 /* set the SvFLAGS specified by mask to the values in val */
234 
235 void
236 Perl_save_set_svflags(pTHX_ SV* sv, U32 mask, U32 val)
237 {
238     dVAR;
239     SSCHECK(4);
240     SSPUSHPTR(sv);
241     SSPUSHINT(mask);
242     SSPUSHINT(val);
243     SSPUSHINT(SAVEt_SET_SVFLAGS);
244 }
245 
246 void
247 Perl_save_gp(pTHX_ GV *gv, I32 empty)
248 {
249     dVAR;
250     SSGROW(3);
251     SSPUSHPTR(SvREFCNT_inc(gv));
252     SSPUSHPTR(GvGP(gv));
253     SSPUSHINT(SAVEt_GP);
254 
255     if (empty) {
256 	GP *gp = Perl_newGP(aTHX_ gv);
257 
258 	if (GvCVu(gv))
259             mro_method_changed_in(GvSTASH(gv)); /* taking a method out of circulation ("local")*/
260 	if (GvIOp(gv) && (IoFLAGS(GvIOp(gv)) & IOf_ARGV)) {
261 	    gp->gp_io = newIO();
262 	    IoFLAGS(gp->gp_io) |= IOf_ARGV|IOf_START;
263 	}
264 #ifdef PERL_DONT_CREATE_GVSV
265 	if (gv == PL_errgv) {
266 	    /* We could scatter this logic everywhere by changing the
267 	       definition of ERRSV from GvSV() to GvSVn(), but it seems more
268 	       efficient to do this check once here.  */
269 	    gp->gp_sv = newSV(0);
270 	}
271 #endif
272 	GvGP(gv) = gp;
273     }
274     else {
275 	gp_ref(GvGP(gv));
276 	GvINTRO_on(gv);
277     }
278 }
279 
280 AV *
281 Perl_save_ary(pTHX_ GV *gv)
282 {
283     dVAR;
284     AV * const oav = GvAVn(gv);
285     AV *av;
286 
287     if (!AvREAL(oav) && AvREIFY(oav))
288 	av_reify(oav);
289     SSCHECK(3);
290     SSPUSHPTR(gv);
291     SSPUSHPTR(oav);
292     SSPUSHINT(SAVEt_AV);
293 
294     GvAV(gv) = NULL;
295     av = GvAVn(gv);
296     if (SvMAGIC(oav))
297 	mg_localize((SV*)oav, (SV*)av);
298     return av;
299 }
300 
301 HV *
302 Perl_save_hash(pTHX_ GV *gv)
303 {
304     dVAR;
305     HV *ohv, *hv;
306 
307     SSCHECK(3);
308     SSPUSHPTR(gv);
309     SSPUSHPTR(ohv = GvHVn(gv));
310     SSPUSHINT(SAVEt_HV);
311 
312     GvHV(gv) = NULL;
313     hv = GvHVn(gv);
314     if (SvMAGIC(ohv))
315 	mg_localize((SV*)ohv, (SV*)hv);
316     return hv;
317 }
318 
319 void
320 Perl_save_item(pTHX_ register SV *item)
321 {
322     dVAR;
323     register SV * const sv = newSVsv(item);
324 
325     SSCHECK(3);
326     SSPUSHPTR(item);		/* remember the pointer */
327     SSPUSHPTR(sv);		/* remember the value */
328     SSPUSHINT(SAVEt_ITEM);
329 }
330 
331 void
332 Perl_save_int(pTHX_ int *intp)
333 {
334     dVAR;
335     SSCHECK(3);
336     SSPUSHINT(*intp);
337     SSPUSHPTR(intp);
338     SSPUSHINT(SAVEt_INT);
339 }
340 
341 void
342 Perl_save_bool(pTHX_ bool *boolp)
343 {
344     dVAR;
345     SSCHECK(3);
346     SSPUSHBOOL(*boolp);
347     SSPUSHPTR(boolp);
348     SSPUSHINT(SAVEt_BOOL);
349 }
350 
351 void
352 Perl_save_I8(pTHX_ I8 *bytep)
353 {
354     dVAR;
355     SSCHECK(3);
356     SSPUSHINT(*bytep);
357     SSPUSHPTR(bytep);
358     SSPUSHINT(SAVEt_I8);
359 }
360 
361 void
362 Perl_save_I16(pTHX_ I16 *intp)
363 {
364     dVAR;
365     SSCHECK(3);
366     SSPUSHINT(*intp);
367     SSPUSHPTR(intp);
368     SSPUSHINT(SAVEt_I16);
369 }
370 
371 void
372 Perl_save_I32(pTHX_ I32 *intp)
373 {
374     dVAR;
375     SSCHECK(3);
376     SSPUSHINT(*intp);
377     SSPUSHPTR(intp);
378     SSPUSHINT(SAVEt_I32);
379 }
380 
381 /* Cannot use save_sptr() to store a char* since the SV** cast will
382  * force word-alignment and we'll miss the pointer.
383  */
384 void
385 Perl_save_pptr(pTHX_ char **pptr)
386 {
387     dVAR;
388     SSCHECK(3);
389     SSPUSHPTR(*pptr);
390     SSPUSHPTR(pptr);
391     SSPUSHINT(SAVEt_PPTR);
392 }
393 
394 void
395 Perl_save_vptr(pTHX_ void *ptr)
396 {
397     dVAR;
398     SSCHECK(3);
399     SSPUSHPTR(*(char**)ptr);
400     SSPUSHPTR(ptr);
401     SSPUSHINT(SAVEt_VPTR);
402 }
403 
404 void
405 Perl_save_sptr(pTHX_ SV **sptr)
406 {
407     dVAR;
408     SSCHECK(3);
409     SSPUSHPTR(*sptr);
410     SSPUSHPTR(sptr);
411     SSPUSHINT(SAVEt_SPTR);
412 }
413 
414 void
415 Perl_save_padsv(pTHX_ PADOFFSET off)
416 {
417     dVAR;
418     SSCHECK(4);
419     ASSERT_CURPAD_ACTIVE("save_padsv");
420     SSPUSHPTR(PL_curpad[off]);
421     SSPUSHPTR(PL_comppad);
422     SSPUSHLONG((long)off);
423     SSPUSHINT(SAVEt_PADSV);
424 }
425 
426 void
427 Perl_save_hptr(pTHX_ HV **hptr)
428 {
429     dVAR;
430     SSCHECK(3);
431     SSPUSHPTR(*hptr);
432     SSPUSHPTR(hptr);
433     SSPUSHINT(SAVEt_HPTR);
434 }
435 
436 void
437 Perl_save_aptr(pTHX_ AV **aptr)
438 {
439     dVAR;
440     SSCHECK(3);
441     SSPUSHPTR(*aptr);
442     SSPUSHPTR(aptr);
443     SSPUSHINT(SAVEt_APTR);
444 }
445 
446 void
447 Perl_save_freesv(pTHX_ SV *sv)
448 {
449     dVAR;
450     SSCHECK(2);
451     SSPUSHPTR(sv);
452     SSPUSHINT(SAVEt_FREESV);
453 }
454 
455 void
456 Perl_save_mortalizesv(pTHX_ SV *sv)
457 {
458     dVAR;
459     SSCHECK(2);
460     SSPUSHPTR(sv);
461     SSPUSHINT(SAVEt_MORTALIZESV);
462 }
463 
464 void
465 Perl_save_freeop(pTHX_ OP *o)
466 {
467     dVAR;
468     SSCHECK(2);
469     SSPUSHPTR(o);
470     SSPUSHINT(SAVEt_FREEOP);
471 }
472 
473 void
474 Perl_save_freepv(pTHX_ char *pv)
475 {
476     dVAR;
477     SSCHECK(2);
478     SSPUSHPTR(pv);
479     SSPUSHINT(SAVEt_FREEPV);
480 }
481 
482 void
483 Perl_save_clearsv(pTHX_ SV **svp)
484 {
485     dVAR;
486     ASSERT_CURPAD_ACTIVE("save_clearsv");
487     SSCHECK(2);
488     SSPUSHLONG((long)(svp-PL_curpad));
489     SSPUSHINT(SAVEt_CLEARSV);
490     SvPADSTALE_off(*svp); /* mark lexical as active */
491 }
492 
493 void
494 Perl_save_delete(pTHX_ HV *hv, char *key, I32 klen)
495 {
496     dVAR;
497     SSCHECK(4);
498     SSPUSHINT(klen);
499     SSPUSHPTR(key);
500     SSPUSHPTR(SvREFCNT_inc_simple(hv));
501     SSPUSHINT(SAVEt_DELETE);
502 }
503 
504 void
505 Perl_save_destructor(pTHX_ DESTRUCTORFUNC_NOCONTEXT_t f, void* p)
506 {
507     dVAR;
508     SSCHECK(3);
509     SSPUSHDPTR(f);
510     SSPUSHPTR(p);
511     SSPUSHINT(SAVEt_DESTRUCTOR);
512 }
513 
514 void
515 Perl_save_destructor_x(pTHX_ DESTRUCTORFUNC_t f, void* p)
516 {
517     dVAR;
518     SSCHECK(3);
519     SSPUSHDXPTR(f);
520     SSPUSHPTR(p);
521     SSPUSHINT(SAVEt_DESTRUCTOR_X);
522 }
523 
524 void
525 Perl_save_aelem(pTHX_ AV *av, I32 idx, SV **sptr)
526 {
527     dVAR;
528     SV *sv;
529     SvGETMAGIC(*sptr);
530     SSCHECK(4);
531     SSPUSHPTR(SvREFCNT_inc_simple(av));
532     SSPUSHINT(idx);
533     SSPUSHPTR(SvREFCNT_inc(*sptr));
534     SSPUSHINT(SAVEt_AELEM);
535     /* if it gets reified later, the restore will have the wrong refcnt */
536     if (!AvREAL(av) && AvREIFY(av))
537 	SvREFCNT_inc_void(*sptr);
538     save_scalar_at(sptr);
539     sv = *sptr;
540     /* If we're localizing a tied array element, this new sv
541      * won't actually be stored in the array - so it won't get
542      * reaped when the localize ends. Ensure it gets reaped by
543      * mortifying it instead. DAPM */
544     if (SvTIED_mg(sv, PERL_MAGIC_tiedelem))
545 	sv_2mortal(sv);
546 }
547 
548 void
549 Perl_save_helem(pTHX_ HV *hv, SV *key, SV **sptr)
550 {
551     dVAR;
552     SV *sv;
553     SvGETMAGIC(*sptr);
554     SSCHECK(4);
555     SSPUSHPTR(SvREFCNT_inc_simple(hv));
556     SSPUSHPTR(newSVsv(key));
557     SSPUSHPTR(SvREFCNT_inc(*sptr));
558     SSPUSHINT(SAVEt_HELEM);
559     save_scalar_at(sptr);
560     sv = *sptr;
561     /* If we're localizing a tied hash element, this new sv
562      * won't actually be stored in the hash - so it won't get
563      * reaped when the localize ends. Ensure it gets reaped by
564      * mortifying it instead. DAPM */
565     if (SvTIED_mg(sv, PERL_MAGIC_tiedelem))
566 	sv_2mortal(sv);
567 }
568 
569 SV*
570 Perl_save_svref(pTHX_ SV **sptr)
571 {
572     dVAR;
573     SvGETMAGIC(*sptr);
574     SSCHECK(3);
575     SSPUSHPTR(sptr);
576     SSPUSHPTR(SvREFCNT_inc(*sptr));
577     SSPUSHINT(SAVEt_SVREF);
578     return save_scalar_at(sptr);
579 }
580 
581 void
582 Perl_save_op(pTHX)
583 {
584     dVAR;
585     SSCHECK(2);
586     SSPUSHPTR(PL_op);
587     SSPUSHINT(SAVEt_OP);
588 }
589 
590 I32
591 Perl_save_alloc(pTHX_ I32 size, I32 pad)
592 {
593     dVAR;
594     register const I32 start = pad + ((char*)&PL_savestack[PL_savestack_ix]
595 				- (char*)PL_savestack);
596     register const I32 elems = 1 + ((size + pad - 1) / sizeof(*PL_savestack));
597 
598     SSGROW(elems + 2);
599 
600     PL_savestack_ix += elems;
601     SSPUSHINT(elems);
602     SSPUSHINT(SAVEt_ALLOC);
603     return start;
604 }
605 
606 void
607 Perl_leave_scope(pTHX_ I32 base)
608 {
609     dVAR;
610     register SV *sv;
611     register SV *value;
612     register GV *gv;
613     register AV *av;
614     register HV *hv;
615     void* ptr;
616     register char* str;
617     I32 i;
618 
619     if (base < -1)
620 	Perl_croak(aTHX_ "panic: corrupt saved stack index");
621     while (PL_savestack_ix > base) {
622 	switch (SSPOPINT) {
623 	case SAVEt_ITEM:			/* normal string */
624 	    value = (SV*)SSPOPPTR;
625 	    sv = (SV*)SSPOPPTR;
626 	    sv_replace(sv,value);
627 	    PL_localizing = 2;
628 	    SvSETMAGIC(sv);
629 	    PL_localizing = 0;
630 	    break;
631 	case SAVEt_SV:				/* scalar reference */
632 	    value = (SV*)SSPOPPTR;
633 	    gv = (GV*)SSPOPPTR;
634 	    ptr = &GvSV(gv);
635 	    av = (AV*)gv; /* what to refcnt_dec */
636 	restore_sv:
637 	    sv = *(SV**)ptr;
638 	    DEBUG_S(PerlIO_printf(Perl_debug_log,
639 				  "restore svref: %p %p:%s -> %p:%s\n",
640 				  (void*)ptr, (void*)sv, SvPEEK(sv),
641 				  (void*)value, SvPEEK(value)));
642 	    *(SV**)ptr = value;
643 	    SvREFCNT_dec(sv);
644 	    PL_localizing = 2;
645 	    SvSETMAGIC(value);
646 	    PL_localizing = 0;
647 	    SvREFCNT_dec(value);
648 	    if (av) /* actually an av, hv or gv */
649 		SvREFCNT_dec(av);
650 	    break;
651 	case SAVEt_GENERIC_PVREF:		/* generic pv */
652 	    ptr = SSPOPPTR;
653 	    str = (char*)SSPOPPTR;
654 	    if (*(char**)ptr != str) {
655 		Safefree(*(char**)ptr);
656 		*(char**)ptr = str;
657 	    }
658 	    break;
659 	case SAVEt_SHARED_PVREF:		/* shared pv */
660 	    str = (char*)SSPOPPTR;
661 	    ptr = SSPOPPTR;
662 	    if (*(char**)ptr != str) {
663 #ifdef NETWARE
664 		PerlMem_free(*(char**)ptr);
665 #else
666 		PerlMemShared_free(*(char**)ptr);
667 #endif
668 		*(char**)ptr = str;
669 	    }
670 	    break;
671 	case SAVEt_GENERIC_SVREF:		/* generic sv */
672 	    value = (SV*)SSPOPPTR;
673 	    ptr = SSPOPPTR;
674 	    sv = *(SV**)ptr;
675 	    *(SV**)ptr = value;
676 	    SvREFCNT_dec(sv);
677 	    SvREFCNT_dec(value);
678 	    break;
679 	case SAVEt_AV:				/* array reference */
680 	    av = (AV*)SSPOPPTR;
681 	    gv = (GV*)SSPOPPTR;
682 	    if (GvAV(gv)) {
683 		SvREFCNT_dec(GvAV(gv));
684 	    }
685 	    GvAV(gv) = av;
686 	    if (SvMAGICAL(av)) {
687 		PL_localizing = 2;
688 		SvSETMAGIC((SV*)av);
689 		PL_localizing = 0;
690 	    }
691 	    break;
692 	case SAVEt_HV:				/* hash reference */
693 	    hv = (HV*)SSPOPPTR;
694 	    gv = (GV*)SSPOPPTR;
695 	    if (GvHV(gv)) {
696 		SvREFCNT_dec(GvHV(gv));
697 	    }
698 	    GvHV(gv) = hv;
699 	    if (SvMAGICAL(hv)) {
700 		PL_localizing = 2;
701 		SvSETMAGIC((SV*)hv);
702 		PL_localizing = 0;
703 	    }
704 	    break;
705 	case SAVEt_INT:				/* int reference */
706 	    ptr = SSPOPPTR;
707 	    *(int*)ptr = (int)SSPOPINT;
708 	    break;
709 	case SAVEt_BOOL:			/* bool reference */
710 	    ptr = SSPOPPTR;
711 	    *(bool*)ptr = (bool)SSPOPBOOL;
712 	    break;
713 	case SAVEt_I32:				/* I32 reference */
714 	    ptr = SSPOPPTR;
715 #ifdef PERL_DEBUG_READONLY_OPS
716 	    {
717 		const I32 val = SSPOPINT;
718 		if (*(I32*)ptr != val)
719 		    *(I32*)ptr = val;
720 	    }
721 #else
722 	    *(I32*)ptr = (I32)SSPOPINT;
723 #endif
724 	    break;
725 	case SAVEt_SPTR:			/* SV* reference */
726 	    ptr = SSPOPPTR;
727 	    *(SV**)ptr = (SV*)SSPOPPTR;
728 	    break;
729 	case SAVEt_VPTR:			/* random* reference */
730 	case SAVEt_PPTR:			/* char* reference */
731 	    ptr = SSPOPPTR;
732 	    *(char**)ptr = (char*)SSPOPPTR;
733 	    break;
734 	case SAVEt_HPTR:			/* HV* reference */
735 	    ptr = SSPOPPTR;
736 	    *(HV**)ptr = (HV*)SSPOPPTR;
737 	    break;
738 	case SAVEt_APTR:			/* AV* reference */
739 	    ptr = SSPOPPTR;
740 	    *(AV**)ptr = (AV*)SSPOPPTR;
741 	    break;
742 	case SAVEt_GP:				/* scalar reference */
743 	    ptr = SSPOPPTR;
744 	    gv = (GV*)SSPOPPTR;
745 	    gp_free(gv);
746 	    GvGP(gv) = (GP*)ptr;
747             /* putting a method back into circulation ("local")*/
748 	    if (GvCVu(gv) && (hv=GvSTASH(gv)) && HvNAME_get(hv))
749                 mro_method_changed_in(hv);
750 	    SvREFCNT_dec(gv);
751 	    break;
752 	case SAVEt_FREESV:
753 	    ptr = SSPOPPTR;
754 	    SvREFCNT_dec((SV*)ptr);
755 	    break;
756 	case SAVEt_MORTALIZESV:
757 	    ptr = SSPOPPTR;
758 	    sv_2mortal((SV*)ptr);
759 	    break;
760 	case SAVEt_FREEOP:
761 	    ptr = SSPOPPTR;
762 	    ASSERT_CURPAD_LEGAL("SAVEt_FREEOP"); /* XXX DAPM tmp */
763 	    op_free((OP*)ptr);
764 	    break;
765 	case SAVEt_FREEPV:
766 	    ptr = SSPOPPTR;
767 	    Safefree(ptr);
768 	    break;
769 	case SAVEt_CLEARSV:
770 	    ptr = (void*)&PL_curpad[SSPOPLONG];
771 	    sv = *(SV**)ptr;
772 
773 	    DEBUG_Xv(PerlIO_printf(Perl_debug_log,
774 	     "Pad 0x%"UVxf"[0x%"UVxf"] clearsv: %ld sv=0x%"UVxf"<%"IVdf"> %s\n",
775 		PTR2UV(PL_comppad), PTR2UV(PL_curpad),
776 		(long)((SV **)ptr-PL_curpad), PTR2UV(sv), (IV)SvREFCNT(sv),
777 		(SvREFCNT(sv) <= 1 && !SvOBJECT(sv)) ? "clear" : "abandon"
778 	    ));
779 
780 	    /* Can clear pad variable in place? */
781 	    if (SvREFCNT(sv) <= 1 && !SvOBJECT(sv)) {
782 		/*
783 		 * if a my variable that was made readonly is going out of
784 		 * scope, we want to remove the readonlyness so that it can
785 		 * go out of scope quietly
786 		 */
787 		if (SvPADMY(sv) && !SvFAKE(sv))
788 		    SvREADONLY_off(sv);
789 
790 		if (SvTHINKFIRST(sv))
791 		    sv_force_normal_flags(sv, SV_IMMEDIATE_UNREF);
792 		if (SvMAGICAL(sv))
793 		    mg_free(sv);
794 
795 		switch (SvTYPE(sv)) {
796 		case SVt_NULL:
797 		    break;
798 		case SVt_PVAV:
799 		    av_clear((AV*)sv);
800 		    break;
801 		case SVt_PVHV:
802 		    hv_clear((HV*)sv);
803 		    break;
804 		case SVt_PVCV:
805 		    Perl_croak(aTHX_ "panic: leave_scope pad code");
806 		default:
807 		    SvOK_off(sv);
808 		    break;
809 		}
810 		SvPADSTALE_on(sv); /* mark as no longer live */
811 	    }
812 	    else {	/* Someone has a claim on this, so abandon it. */
813 		const U32 padflags = SvFLAGS(sv) & (SVs_PADMY|SVs_PADTMP);
814 		switch (SvTYPE(sv)) {	/* Console ourselves with a new value */
815 		case SVt_PVAV:	*(SV**)ptr = (SV*)newAV();	break;
816 		case SVt_PVHV:	*(SV**)ptr = (SV*)newHV();	break;
817 		default:	*(SV**)ptr = newSV(0);		break;
818 		}
819 		SvREFCNT_dec(sv);	/* Cast current value to the winds. */
820 		/* preserve pad nature, but also mark as not live
821 		 * for any closure capturing */
822 		SvFLAGS(*(SV**)ptr) |= padflags | SVs_PADSTALE;
823 	    }
824 	    break;
825 	case SAVEt_DELETE:
826 	    ptr = SSPOPPTR;
827 	    hv = (HV*)ptr;
828 	    ptr = SSPOPPTR;
829 	    (void)hv_delete(hv, (char*)ptr, (I32)SSPOPINT, G_DISCARD);
830 	    SvREFCNT_dec(hv);
831 	    Safefree(ptr);
832 	    break;
833 	case SAVEt_DESTRUCTOR_X:
834 	    ptr = SSPOPPTR;
835 	    (*SSPOPDXPTR)(aTHX_ ptr);
836 	    break;
837 	case SAVEt_REGCONTEXT:
838 	case SAVEt_ALLOC:
839 	    i = SSPOPINT;
840 	    PL_savestack_ix -= i;  	/* regexp must have croaked */
841 	    break;
842 	case SAVEt_STACK_POS:		/* Position on Perl stack */
843 	    i = SSPOPINT;
844 	    PL_stack_sp = PL_stack_base + i;
845 	    break;
846 	case SAVEt_STACK_CXPOS:         /* blk_oldsp on context stack */
847 	    i = SSPOPINT;
848 	    cxstack[i].blk_oldsp = SSPOPINT;
849 	    break;
850 	case SAVEt_AELEM:		/* array element */
851 	    value = (SV*)SSPOPPTR;
852 	    i = SSPOPINT;
853 	    av = (AV*)SSPOPPTR;
854 	    ptr = av_fetch(av,i,1);
855 	    if (!AvREAL(av) && AvREIFY(av)) /* undo reify guard */
856 		SvREFCNT_dec(value);
857 	    if (ptr) {
858 		sv = *(SV**)ptr;
859 		if (sv && sv != &PL_sv_undef) {
860 		    if (SvTIED_mg((SV*)av, PERL_MAGIC_tied))
861 			SvREFCNT_inc_void_NN(sv);
862 		    goto restore_sv;
863 		}
864 	    }
865 	    SvREFCNT_dec(av);
866 	    SvREFCNT_dec(value);
867 	    break;
868 	case SAVEt_HELEM:		/* hash element */
869 	    value = (SV*)SSPOPPTR;
870 	    sv = (SV*)SSPOPPTR;
871 	    hv = (HV*)SSPOPPTR;
872 	    ptr = hv_fetch_ent(hv, sv, 1, 0);
873 	    if (ptr) {
874 		const SV * const oval = HeVAL((HE*)ptr);
875 		if (oval && oval != &PL_sv_undef) {
876 		    ptr = &HeVAL((HE*)ptr);
877 		    if (SvTIED_mg((SV*)hv, PERL_MAGIC_tied))
878 			SvREFCNT_inc_void(*(SV**)ptr);
879 		    SvREFCNT_dec(sv);
880 		    av = (AV*)hv; /* what to refcnt_dec */
881 		    goto restore_sv;
882 		}
883 	    }
884 	    SvREFCNT_dec(hv);
885 	    SvREFCNT_dec(sv);
886 	    SvREFCNT_dec(value);
887 	    break;
888 	case SAVEt_OP:
889 	    PL_op = (OP*)SSPOPPTR;
890 	    break;
891 	case SAVEt_HINTS:
892 	    if ((PL_hints & HINT_LOCALIZE_HH) && GvHV(PL_hintgv)) {
893 		SvREFCNT_dec((SV*)GvHV(PL_hintgv));
894 		GvHV(PL_hintgv) = NULL;
895 	    }
896 	    *(I32*)&PL_hints = (I32)SSPOPINT;
897 	    Perl_refcounted_he_free(aTHX_ PL_compiling.cop_hints_hash);
898 	    PL_compiling.cop_hints_hash = (struct refcounted_he *) SSPOPPTR;
899 	    if (PL_hints & HINT_LOCALIZE_HH) {
900 		SvREFCNT_dec((SV*)GvHV(PL_hintgv));
901 		GvHV(PL_hintgv) = (HV*)SSPOPPTR;
902 		assert(GvHV(PL_hintgv));
903 	    } else if (!GvHV(PL_hintgv)) {
904 		/* Need to add a new one manually, else gv_fetchpv() can
905 		   add one in this code:
906 
907 		   if (SvTYPE(gv) == SVt_PVGV) {
908 		       if (add) {
909 		       GvMULTI_on(gv);
910 		       gv_init_sv(gv, sv_type);
911 		       if (*name=='!' && sv_type == SVt_PVHV && len==1)
912 			   require_errno(gv);
913 		       }
914 		       return gv;
915 		   }
916 
917 		   and it won't have the magic set.  */
918 
919 		HV *const hv = newHV();
920 		hv_magic(hv, NULL, PERL_MAGIC_hints);
921 		GvHV(PL_hintgv) = hv;
922 	    }
923 	    assert(GvHV(PL_hintgv));
924 	    break;
925 	case SAVEt_COMPPAD:
926 	    PL_comppad = (PAD*)SSPOPPTR;
927 	    if (PL_comppad)
928 		PL_curpad = AvARRAY(PL_comppad);
929 	    else
930 		PL_curpad = NULL;
931 	    break;
932 	case SAVEt_PADSV:
933 	    {
934 		const PADOFFSET off = (PADOFFSET)SSPOPLONG;
935 		ptr = SSPOPPTR;
936 		if (ptr)
937 		    AvARRAY((PAD*)ptr)[off] = (SV*)SSPOPPTR;
938 	    }
939 	    break;
940 	case SAVEt_SAVESWITCHSTACK:
941 	    {
942 		dSP;
943 		AV* const t = (AV*)SSPOPPTR;
944 		AV* const f = (AV*)SSPOPPTR;
945 		SWITCHSTACK(t,f);
946 		PL_curstackinfo->si_stack = f;
947 	    }
948 	    break;
949 	case SAVEt_SET_SVFLAGS:
950 	    {
951 		const U32 val  = (U32)SSPOPINT;
952 		const U32 mask = (U32)SSPOPINT;
953 		sv = (SV*)SSPOPPTR;
954 		SvFLAGS(sv) &= ~mask;
955 		SvFLAGS(sv) |= val;
956 	    }
957 	    break;
958 	    /* These are only saved in mathoms.c */
959 	case SAVEt_SVREF:			/* scalar reference */
960 	    value = (SV*)SSPOPPTR;
961 	    ptr = SSPOPPTR;
962 	    av = NULL; /* what to refcnt_dec */
963 	    goto restore_sv;
964 	case SAVEt_LONG:			/* long reference */
965 	    ptr = SSPOPPTR;
966 	    *(long*)ptr = (long)SSPOPLONG;
967 	    break;
968 	case SAVEt_I16:				/* I16 reference */
969 	    ptr = SSPOPPTR;
970 	    *(I16*)ptr = (I16)SSPOPINT;
971 	    break;
972 	case SAVEt_I8:				/* I8 reference */
973 	    ptr = SSPOPPTR;
974 	    *(I8*)ptr = (I8)SSPOPINT;
975 	    break;
976 	case SAVEt_IV:				/* IV reference */
977 	    ptr = SSPOPPTR;
978 	    *(IV*)ptr = (IV)SSPOPIV;
979 	    break;
980 	case SAVEt_NSTAB:
981 	    gv = (GV*)SSPOPPTR;
982 	    (void)sv_clear((SV*)gv);
983 	    break;
984 	case SAVEt_DESTRUCTOR:
985 	    ptr = SSPOPPTR;
986 	    (*SSPOPDPTR)(ptr);
987 	    break;
988 	case SAVEt_COP_ARYBASE:
989 	    ptr = SSPOPPTR;
990 	    i = SSPOPINT;
991 	    CopARYBASE_set((COP *)ptr, i);
992 	    break;
993 	case SAVEt_COMPILE_WARNINGS:
994 	    ptr = SSPOPPTR;
995 
996 	    if (!specialWARN(PL_compiling.cop_warnings))
997 		PerlMemShared_free(PL_compiling.cop_warnings);
998 
999 	    PL_compiling.cop_warnings = (STRLEN*)ptr;
1000 	    break;
1001 	case SAVEt_RE_STATE:
1002 	    {
1003 		const struct re_save_state *const state
1004 		    = (struct re_save_state *)
1005 		    (PL_savestack + PL_savestack_ix
1006 		     - SAVESTACK_ALLOC_FOR_RE_SAVE_STATE);
1007 		PL_savestack_ix -= SAVESTACK_ALLOC_FOR_RE_SAVE_STATE;
1008 
1009 		if (PL_reg_start_tmp != state->re_state_reg_start_tmp) {
1010 		    Safefree(PL_reg_start_tmp);
1011 		}
1012 		if (PL_reg_poscache != state->re_state_reg_poscache) {
1013 		    Safefree(PL_reg_poscache);
1014 		}
1015 		Copy(state, &PL_reg_state, 1, struct re_save_state);
1016 	    }
1017 	    break;
1018 	case SAVEt_PARSER:
1019 	    ptr = SSPOPPTR;
1020 	    parser_free((yy_parser *) ptr);
1021 	    break;
1022 	default:
1023 	    Perl_croak(aTHX_ "panic: leave_scope inconsistency");
1024 	}
1025     }
1026 }
1027 
1028 void
1029 Perl_cx_dump(pTHX_ PERL_CONTEXT *cx)
1030 {
1031     dVAR;
1032 #ifdef DEBUGGING
1033     PerlIO_printf(Perl_debug_log, "CX %ld = %s\n", (long)(cx - cxstack), PL_block_type[CxTYPE(cx)]);
1034     if (CxTYPE(cx) != CXt_SUBST) {
1035 	PerlIO_printf(Perl_debug_log, "BLK_OLDSP = %ld\n", (long)cx->blk_oldsp);
1036 	PerlIO_printf(Perl_debug_log, "BLK_OLDCOP = 0x%"UVxf"\n",
1037 		      PTR2UV(cx->blk_oldcop));
1038 	PerlIO_printf(Perl_debug_log, "BLK_OLDMARKSP = %ld\n", (long)cx->blk_oldmarksp);
1039 	PerlIO_printf(Perl_debug_log, "BLK_OLDSCOPESP = %ld\n", (long)cx->blk_oldscopesp);
1040 	PerlIO_printf(Perl_debug_log, "BLK_OLDPM = 0x%"UVxf"\n",
1041 		      PTR2UV(cx->blk_oldpm));
1042 	PerlIO_printf(Perl_debug_log, "BLK_GIMME = %s\n", cx->blk_gimme ? "LIST" : "SCALAR");
1043     }
1044     switch (CxTYPE(cx)) {
1045     case CXt_NULL:
1046     case CXt_BLOCK:
1047 	break;
1048     case CXt_FORMAT:
1049 	PerlIO_printf(Perl_debug_log, "BLK_SUB.CV = 0x%"UVxf"\n",
1050 		PTR2UV(cx->blk_sub.cv));
1051 	PerlIO_printf(Perl_debug_log, "BLK_SUB.GV = 0x%"UVxf"\n",
1052 		PTR2UV(cx->blk_sub.gv));
1053 	PerlIO_printf(Perl_debug_log, "BLK_SUB.DFOUTGV = 0x%"UVxf"\n",
1054 		PTR2UV(cx->blk_sub.dfoutgv));
1055 	PerlIO_printf(Perl_debug_log, "BLK_SUB.HASARGS = %d\n",
1056 		(int)cx->blk_sub.hasargs);
1057 	PerlIO_printf(Perl_debug_log, "BLK_SUB.RETOP = 0x%"UVxf"\n",
1058 		PTR2UV(cx->blk_sub.retop));
1059 	break;
1060     case CXt_SUB:
1061 	PerlIO_printf(Perl_debug_log, "BLK_SUB.CV = 0x%"UVxf"\n",
1062 		PTR2UV(cx->blk_sub.cv));
1063 	PerlIO_printf(Perl_debug_log, "BLK_SUB.OLDDEPTH = %ld\n",
1064 		(long)cx->blk_sub.olddepth);
1065 	PerlIO_printf(Perl_debug_log, "BLK_SUB.HASARGS = %d\n",
1066 		(int)cx->blk_sub.hasargs);
1067 	PerlIO_printf(Perl_debug_log, "BLK_SUB.LVAL = %d\n",
1068 		(int)cx->blk_sub.lval);
1069 	PerlIO_printf(Perl_debug_log, "BLK_SUB.RETOP = 0x%"UVxf"\n",
1070 		PTR2UV(cx->blk_sub.retop));
1071 	break;
1072     case CXt_EVAL:
1073 	PerlIO_printf(Perl_debug_log, "BLK_EVAL.OLD_IN_EVAL = %ld\n",
1074 		(long)cx->blk_eval.old_in_eval);
1075 	PerlIO_printf(Perl_debug_log, "BLK_EVAL.OLD_OP_TYPE = %s (%s)\n",
1076 		PL_op_name[cx->blk_eval.old_op_type],
1077 		PL_op_desc[cx->blk_eval.old_op_type]);
1078 	if (cx->blk_eval.old_namesv)
1079 	    PerlIO_printf(Perl_debug_log, "BLK_EVAL.OLD_NAME = %s\n",
1080 			  SvPVX_const(cx->blk_eval.old_namesv));
1081 	PerlIO_printf(Perl_debug_log, "BLK_EVAL.OLD_EVAL_ROOT = 0x%"UVxf"\n",
1082 		PTR2UV(cx->blk_eval.old_eval_root));
1083 	PerlIO_printf(Perl_debug_log, "BLK_EVAL.RETOP = 0x%"UVxf"\n",
1084 		PTR2UV(cx->blk_eval.retop));
1085 	break;
1086 
1087     case CXt_LOOP:
1088 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.LABEL = %s\n",
1089 		cx->blk_loop.label);
1090 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.RESETSP = %ld\n",
1091 		(long)cx->blk_loop.resetsp);
1092 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.MY_OP = 0x%"UVxf"\n",
1093 		PTR2UV(cx->blk_loop.my_op));
1094 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.NEXT_OP = 0x%"UVxf"\n",
1095 		PTR2UV(CX_LOOP_NEXTOP_GET(cx)));
1096 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.ITERIX = %ld\n",
1097 		(long)cx->blk_loop.iterix);
1098 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.ITERARY = 0x%"UVxf"\n",
1099 		PTR2UV(cx->blk_loop.iterary));
1100 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.ITERVAR = 0x%"UVxf"\n",
1101 		PTR2UV(CxITERVAR(cx)));
1102 	if (CxITERVAR(cx))
1103 	    PerlIO_printf(Perl_debug_log, "BLK_LOOP.ITERSAVE = 0x%"UVxf"\n",
1104 		PTR2UV(cx->blk_loop.itersave));
1105 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.ITERLVAL = 0x%"UVxf"\n",
1106 		PTR2UV(cx->blk_loop.iterlval));
1107 	break;
1108 
1109     case CXt_SUBST:
1110 	PerlIO_printf(Perl_debug_log, "SB_ITERS = %ld\n",
1111 		(long)cx->sb_iters);
1112 	PerlIO_printf(Perl_debug_log, "SB_MAXITERS = %ld\n",
1113 		(long)cx->sb_maxiters);
1114 	PerlIO_printf(Perl_debug_log, "SB_RFLAGS = %ld\n",
1115 		(long)cx->sb_rflags);
1116 	PerlIO_printf(Perl_debug_log, "SB_ONCE = %ld\n",
1117 		(long)cx->sb_once);
1118 	PerlIO_printf(Perl_debug_log, "SB_ORIG = %s\n",
1119 		cx->sb_orig);
1120 	PerlIO_printf(Perl_debug_log, "SB_DSTR = 0x%"UVxf"\n",
1121 		PTR2UV(cx->sb_dstr));
1122 	PerlIO_printf(Perl_debug_log, "SB_TARG = 0x%"UVxf"\n",
1123 		PTR2UV(cx->sb_targ));
1124 	PerlIO_printf(Perl_debug_log, "SB_S = 0x%"UVxf"\n",
1125 		PTR2UV(cx->sb_s));
1126 	PerlIO_printf(Perl_debug_log, "SB_M = 0x%"UVxf"\n",
1127 		PTR2UV(cx->sb_m));
1128 	PerlIO_printf(Perl_debug_log, "SB_STREND = 0x%"UVxf"\n",
1129 		PTR2UV(cx->sb_strend));
1130 	PerlIO_printf(Perl_debug_log, "SB_RXRES = 0x%"UVxf"\n",
1131 		PTR2UV(cx->sb_rxres));
1132 	break;
1133     }
1134 #else
1135     PERL_UNUSED_CONTEXT;
1136     PERL_UNUSED_ARG(cx);
1137 #endif	/* DEBUGGING */
1138 }
1139 
1140 /*
1141  * Local variables:
1142  * c-indentation-style: bsd
1143  * c-basic-offset: 4
1144  * indent-tabs-mode: t
1145  * End:
1146  *
1147  * ex: set ts=8 sts=4 sw=4 noet:
1148  */
1149