xref: /openbsd-src/gnu/usr.bin/perl/scope.c (revision b2ea75c1b17e1a9a339660e7ed45cd24946b230e)
1 /*    scope.c
2  *
3  *    Copyright (c) 1991-2001, Larry Wall
4  *
5  *    You may distribute under the terms of either the GNU General Public
6  *    License or the Artistic License, as specified in the README file.
7  *
8  */
9 
10 /*
11  * "For the fashion of Minas Tirith was such that it was built on seven
12  * levels..."
13  */
14 
15 #include "EXTERN.h"
16 #define PERL_IN_SCOPE_C
17 #include "perl.h"
18 
19 #if defined(PERL_FLEXIBLE_EXCEPTIONS)
20 void *
21 Perl_default_protect(pTHX_ volatile JMPENV *pcur_env, int *excpt,
22 		     protect_body_t body, ...)
23 {
24     void *ret;
25     va_list args;
26     va_start(args, body);
27     ret = vdefault_protect(pcur_env, excpt, body, &args);
28     va_end(args);
29     return ret;
30 }
31 
32 void *
33 Perl_vdefault_protect(pTHX_ volatile JMPENV *pcur_env, int *excpt,
34 		      protect_body_t body, va_list *args)
35 {
36     int ex;
37     void *ret;
38 
39     JMPENV_PUSH(ex);
40     if (ex)
41 	ret = NULL;
42     else
43 	ret = CALL_FPTR(body)(aTHX_ *args);
44     *excpt = ex;
45     JMPENV_POP;
46     return ret;
47 }
48 #endif
49 
50 SV**
51 Perl_stack_grow(pTHX_ SV **sp, SV **p, int n)
52 {
53 #if defined(DEBUGGING) && !defined(USE_THREADS)
54     static int growing = 0;
55     if (growing++)
56       abort();
57 #endif
58     PL_stack_sp = sp;
59 #ifndef STRESS_REALLOC
60     av_extend(PL_curstack, (p - PL_stack_base) + (n) + 128);
61 #else
62     av_extend(PL_curstack, (p - PL_stack_base) + (n) + 1);
63 #endif
64 #if defined(DEBUGGING) && !defined(USE_THREADS)
65     growing--;
66 #endif
67     return PL_stack_sp;
68 }
69 
70 #ifndef STRESS_REALLOC
71 #define GROW(old) ((old) * 3 / 2)
72 #else
73 #define GROW(old) ((old) + 1)
74 #endif
75 
76 PERL_SI *
77 Perl_new_stackinfo(pTHX_ I32 stitems, I32 cxitems)
78 {
79     PERL_SI *si;
80     New(56, si, 1, PERL_SI);
81     si->si_stack = newAV();
82     AvREAL_off(si->si_stack);
83     av_extend(si->si_stack, stitems > 0 ? stitems-1 : 0);
84     AvALLOC(si->si_stack)[0] = &PL_sv_undef;
85     AvFILLp(si->si_stack) = 0;
86     si->si_prev = 0;
87     si->si_next = 0;
88     si->si_cxmax = cxitems - 1;
89     si->si_cxix = -1;
90     si->si_type = PERLSI_UNDEF;
91     New(56, si->si_cxstack, cxitems, PERL_CONTEXT);
92     return si;
93 }
94 
95 I32
96 Perl_cxinc(pTHX)
97 {
98     cxstack_max = GROW(cxstack_max);
99     Renew(cxstack, cxstack_max + 1, PERL_CONTEXT);	/* XXX should fix CXINC macro */
100     return cxstack_ix + 1;
101 }
102 
103 void
104 Perl_push_return(pTHX_ OP *retop)
105 {
106     if (PL_retstack_ix == PL_retstack_max) {
107 	PL_retstack_max = GROW(PL_retstack_max);
108 	Renew(PL_retstack, PL_retstack_max, OP*);
109     }
110     PL_retstack[PL_retstack_ix++] = retop;
111 }
112 
113 OP *
114 Perl_pop_return(pTHX)
115 {
116     if (PL_retstack_ix > 0)
117 	return PL_retstack[--PL_retstack_ix];
118     else
119 	return Nullop;
120 }
121 
122 void
123 Perl_push_scope(pTHX)
124 {
125     if (PL_scopestack_ix == PL_scopestack_max) {
126 	PL_scopestack_max = GROW(PL_scopestack_max);
127 	Renew(PL_scopestack, PL_scopestack_max, I32);
128     }
129     PL_scopestack[PL_scopestack_ix++] = PL_savestack_ix;
130 
131 }
132 
133 void
134 Perl_pop_scope(pTHX)
135 {
136     I32 oldsave = PL_scopestack[--PL_scopestack_ix];
137     LEAVE_SCOPE(oldsave);
138 }
139 
140 void
141 Perl_markstack_grow(pTHX)
142 {
143     I32 oldmax = PL_markstack_max - PL_markstack;
144     I32 newmax = GROW(oldmax);
145 
146     Renew(PL_markstack, newmax, I32);
147     PL_markstack_ptr = PL_markstack + oldmax;
148     PL_markstack_max = PL_markstack + newmax;
149 }
150 
151 void
152 Perl_savestack_grow(pTHX)
153 {
154     PL_savestack_max = GROW(PL_savestack_max) + 4;
155     Renew(PL_savestack, PL_savestack_max, ANY);
156 }
157 
158 #undef GROW
159 
160 void
161 Perl_tmps_grow(pTHX_ I32 n)
162 {
163 #ifndef STRESS_REALLOC
164     if (n < 128)
165 	n = (PL_tmps_max < 512) ? 128 : 512;
166 #endif
167     PL_tmps_max = PL_tmps_ix + n + 1;
168     Renew(PL_tmps_stack, PL_tmps_max, SV*);
169 }
170 
171 
172 void
173 Perl_free_tmps(pTHX)
174 {
175     /* XXX should tmps_floor live in cxstack? */
176     I32 myfloor = PL_tmps_floor;
177     while (PL_tmps_ix > myfloor) {      /* clean up after last statement */
178 	SV* sv = PL_tmps_stack[PL_tmps_ix];
179 	PL_tmps_stack[PL_tmps_ix--] = Nullsv;
180 	if (sv) {
181 	    SvTEMP_off(sv);
182 	    SvREFCNT_dec(sv);		/* note, can modify tmps_ix!!! */
183 	}
184     }
185 }
186 
187 STATIC SV *
188 S_save_scalar_at(pTHX_ SV **sptr)
189 {
190     register SV *sv;
191     SV *osv = *sptr;
192 
193     sv = *sptr = NEWSV(0,0);
194     if (SvTYPE(osv) >= SVt_PVMG && SvMAGIC(osv) && SvTYPE(osv) != SVt_PVGV) {
195 	sv_upgrade(sv, SvTYPE(osv));
196 	if (SvGMAGICAL(osv)) {
197 	    MAGIC* mg;
198 	    bool oldtainted = PL_tainted;
199 	    mg_get(osv);		/* note, can croak! */
200 	    if (PL_tainting && PL_tainted && (mg = mg_find(osv, 't'))) {
201 		SAVESPTR(mg->mg_obj);
202 		mg->mg_obj = osv;
203 	    }
204 	    SvFLAGS(osv) |= (SvFLAGS(osv) &
205 		(SVp_IOK|SVp_NOK|SVp_POK)) >> PRIVSHIFT;
206 	    PL_tainted = oldtainted;
207 	}
208 	SvMAGIC(sv) = SvMAGIC(osv);
209 	SvFLAGS(sv) |= SvMAGICAL(osv);
210 	/* XXX SvMAGIC() is *shared* between osv and sv.  This can
211 	 * lead to coredumps when both SVs are destroyed without one
212 	 * of their SvMAGIC() slots being NULLed. */
213 	PL_localizing = 1;
214 	SvSETMAGIC(sv);
215 	PL_localizing = 0;
216     }
217     return sv;
218 }
219 
220 SV *
221 Perl_save_scalar(pTHX_ GV *gv)
222 {
223     SV **sptr = &GvSV(gv);
224     SSCHECK(3);
225     SSPUSHPTR(SvREFCNT_inc(gv));
226     SSPUSHPTR(SvREFCNT_inc(*sptr));
227     SSPUSHINT(SAVEt_SV);
228     return save_scalar_at(sptr);
229 }
230 
231 SV*
232 Perl_save_svref(pTHX_ SV **sptr)
233 {
234     SSCHECK(3);
235     SSPUSHPTR(sptr);
236     SSPUSHPTR(SvREFCNT_inc(*sptr));
237     SSPUSHINT(SAVEt_SVREF);
238     return save_scalar_at(sptr);
239 }
240 
241 /* Like save_sptr(), but also SvREFCNT_dec()s the new value.  Can be used to
242  * restore a global SV to its prior contents, freeing new value. */
243 void
244 Perl_save_generic_svref(pTHX_ SV **sptr)
245 {
246     SSCHECK(3);
247     SSPUSHPTR(sptr);
248     SSPUSHPTR(SvREFCNT_inc(*sptr));
249     SSPUSHINT(SAVEt_GENERIC_SVREF);
250 }
251 
252 /* Like save_pptr(), but also Safefree()s the new value if it is different
253  * from the old one.  Can be used to restore a global char* to its prior
254  * contents, freeing new value. */
255 void
256 Perl_save_generic_pvref(pTHX_ char **str)
257 {
258     SSCHECK(3);
259     SSPUSHPTR(str);
260     SSPUSHPTR(*str);
261     SSPUSHINT(SAVEt_GENERIC_PVREF);
262 }
263 
264 void
265 Perl_save_gp(pTHX_ GV *gv, I32 empty)
266 {
267     SSCHECK(6);
268     SSPUSHIV((IV)SvLEN(gv));
269     SvLEN(gv) = 0; /* forget that anything was allocated here */
270     SSPUSHIV((IV)SvCUR(gv));
271     SSPUSHPTR(SvPVX(gv));
272     SvPOK_off(gv);
273     SSPUSHPTR(SvREFCNT_inc(gv));
274     SSPUSHPTR(GvGP(gv));
275     SSPUSHINT(SAVEt_GP);
276 
277     if (empty) {
278 	register GP *gp;
279 
280 	Newz(602, gp, 1, GP);
281 
282 	if (GvCVu(gv))
283 	    PL_sub_generation++;	/* taking a method out of circulation */
284 	if (GvIOp(gv) && (IoFLAGS(GvIOp(gv)) & IOf_ARGV)) {
285 	    gp->gp_io = newIO();
286 	    IoFLAGS(gp->gp_io) |= IOf_ARGV|IOf_START;
287 	}
288 	GvGP(gv) = gp_ref(gp);
289 	GvSV(gv) = NEWSV(72,0);
290 	GvLINE(gv) = CopLINE(PL_curcop);
291 	GvFILE(gv) = CopFILE(PL_curcop) ? CopFILE(PL_curcop) : "";
292 	GvEGV(gv) = gv;
293     }
294     else {
295 	gp_ref(GvGP(gv));
296 	GvINTRO_on(gv);
297     }
298 }
299 
300 AV *
301 Perl_save_ary(pTHX_ GV *gv)
302 {
303     AV *oav = GvAVn(gv);
304     AV *av;
305 
306     if (!AvREAL(oav) && AvREIFY(oav))
307 	av_reify(oav);
308     SSCHECK(3);
309     SSPUSHPTR(gv);
310     SSPUSHPTR(oav);
311     SSPUSHINT(SAVEt_AV);
312 
313     GvAV(gv) = Null(AV*);
314     av = GvAVn(gv);
315     if (SvMAGIC(oav)) {
316 	SvMAGIC(av) = SvMAGIC(oav);
317 	SvFLAGS((SV*)av) |= SvMAGICAL(oav);
318 	SvMAGICAL_off(oav);
319 	SvMAGIC(oav) = 0;
320 	PL_localizing = 1;
321 	SvSETMAGIC((SV*)av);
322 	PL_localizing = 0;
323     }
324     return av;
325 }
326 
327 HV *
328 Perl_save_hash(pTHX_ GV *gv)
329 {
330     HV *ohv, *hv;
331 
332     SSCHECK(3);
333     SSPUSHPTR(gv);
334     SSPUSHPTR(ohv = GvHVn(gv));
335     SSPUSHINT(SAVEt_HV);
336 
337     GvHV(gv) = Null(HV*);
338     hv = GvHVn(gv);
339     if (SvMAGIC(ohv)) {
340 	SvMAGIC(hv) = SvMAGIC(ohv);
341 	SvFLAGS((SV*)hv) |= SvMAGICAL(ohv);
342 	SvMAGICAL_off(ohv);
343 	SvMAGIC(ohv) = 0;
344 	PL_localizing = 1;
345 	SvSETMAGIC((SV*)hv);
346 	PL_localizing = 0;
347     }
348     return hv;
349 }
350 
351 void
352 Perl_save_item(pTHX_ register SV *item)
353 {
354     register SV *sv = NEWSV(0,0);
355 
356     sv_setsv(sv,item);
357     SSCHECK(3);
358     SSPUSHPTR(item);		/* remember the pointer */
359     SSPUSHPTR(sv);		/* remember the value */
360     SSPUSHINT(SAVEt_ITEM);
361 }
362 
363 void
364 Perl_save_int(pTHX_ int *intp)
365 {
366     SSCHECK(3);
367     SSPUSHINT(*intp);
368     SSPUSHPTR(intp);
369     SSPUSHINT(SAVEt_INT);
370 }
371 
372 void
373 Perl_save_long(pTHX_ long int *longp)
374 {
375     SSCHECK(3);
376     SSPUSHLONG(*longp);
377     SSPUSHPTR(longp);
378     SSPUSHINT(SAVEt_LONG);
379 }
380 
381 void
382 Perl_save_I32(pTHX_ I32 *intp)
383 {
384     SSCHECK(3);
385     SSPUSHINT(*intp);
386     SSPUSHPTR(intp);
387     SSPUSHINT(SAVEt_I32);
388 }
389 
390 void
391 Perl_save_I16(pTHX_ I16 *intp)
392 {
393     SSCHECK(3);
394     SSPUSHINT(*intp);
395     SSPUSHPTR(intp);
396     SSPUSHINT(SAVEt_I16);
397 }
398 
399 void
400 Perl_save_I8(pTHX_ I8 *bytep)
401 {
402     SSCHECK(3);
403     SSPUSHINT(*bytep);
404     SSPUSHPTR(bytep);
405     SSPUSHINT(SAVEt_I8);
406 }
407 
408 void
409 Perl_save_iv(pTHX_ IV *ivp)
410 {
411     SSCHECK(3);
412     SSPUSHIV(*ivp);
413     SSPUSHPTR(ivp);
414     SSPUSHINT(SAVEt_IV);
415 }
416 
417 /* Cannot use save_sptr() to store a char* since the SV** cast will
418  * force word-alignment and we'll miss the pointer.
419  */
420 void
421 Perl_save_pptr(pTHX_ char **pptr)
422 {
423     SSCHECK(3);
424     SSPUSHPTR(*pptr);
425     SSPUSHPTR(pptr);
426     SSPUSHINT(SAVEt_PPTR);
427 }
428 
429 void
430 Perl_save_vptr(pTHX_ void *ptr)
431 {
432     SSCHECK(3);
433     SSPUSHPTR(*(char**)ptr);
434     SSPUSHPTR(ptr);
435     SSPUSHINT(SAVEt_VPTR);
436 }
437 
438 void
439 Perl_save_sptr(pTHX_ SV **sptr)
440 {
441     SSCHECK(3);
442     SSPUSHPTR(*sptr);
443     SSPUSHPTR(sptr);
444     SSPUSHINT(SAVEt_SPTR);
445 }
446 
447 void
448 Perl_save_padsv(pTHX_ PADOFFSET off)
449 {
450     SSCHECK(4);
451     SSPUSHPTR(PL_curpad[off]);
452     SSPUSHPTR(PL_curpad);
453     SSPUSHLONG((long)off);
454     SSPUSHINT(SAVEt_PADSV);
455 }
456 
457 SV **
458 Perl_save_threadsv(pTHX_ PADOFFSET i)
459 {
460 #ifdef USE_THREADS
461     SV **svp = &THREADSV(i);	/* XXX Change to save by offset */
462     DEBUG_S(PerlIO_printf(Perl_debug_log, "save_threadsv %"UVuf": %p %p:%s\n",
463 			  (UV)i, svp, *svp, SvPEEK(*svp)));
464     save_svref(svp);
465     return svp;
466 #else
467     Perl_croak(aTHX_ "panic: save_threadsv called in non-threaded perl");
468     return 0;
469 #endif /* USE_THREADS */
470 }
471 
472 void
473 Perl_save_nogv(pTHX_ GV *gv)
474 {
475     SSCHECK(2);
476     SSPUSHPTR(gv);
477     SSPUSHINT(SAVEt_NSTAB);
478 }
479 
480 void
481 Perl_save_hptr(pTHX_ HV **hptr)
482 {
483     SSCHECK(3);
484     SSPUSHPTR(*hptr);
485     SSPUSHPTR(hptr);
486     SSPUSHINT(SAVEt_HPTR);
487 }
488 
489 void
490 Perl_save_aptr(pTHX_ AV **aptr)
491 {
492     SSCHECK(3);
493     SSPUSHPTR(*aptr);
494     SSPUSHPTR(aptr);
495     SSPUSHINT(SAVEt_APTR);
496 }
497 
498 void
499 Perl_save_freesv(pTHX_ SV *sv)
500 {
501     SSCHECK(2);
502     SSPUSHPTR(sv);
503     SSPUSHINT(SAVEt_FREESV);
504 }
505 
506 void
507 Perl_save_mortalizesv(pTHX_ SV *sv)
508 {
509     SSCHECK(2);
510     SSPUSHPTR(sv);
511     SSPUSHINT(SAVEt_MORTALIZESV);
512 }
513 
514 void
515 Perl_save_freeop(pTHX_ OP *o)
516 {
517     SSCHECK(2);
518     SSPUSHPTR(o);
519     SSPUSHINT(SAVEt_FREEOP);
520 }
521 
522 void
523 Perl_save_freepv(pTHX_ char *pv)
524 {
525     SSCHECK(2);
526     SSPUSHPTR(pv);
527     SSPUSHINT(SAVEt_FREEPV);
528 }
529 
530 void
531 Perl_save_clearsv(pTHX_ SV **svp)
532 {
533     SSCHECK(2);
534     SSPUSHLONG((long)(svp-PL_curpad));
535     SSPUSHINT(SAVEt_CLEARSV);
536 }
537 
538 void
539 Perl_save_delete(pTHX_ HV *hv, char *key, I32 klen)
540 {
541     SSCHECK(4);
542     SSPUSHINT(klen);
543     SSPUSHPTR(key);
544     SSPUSHPTR(SvREFCNT_inc(hv));
545     SSPUSHINT(SAVEt_DELETE);
546 }
547 
548 void
549 Perl_save_list(pTHX_ register SV **sarg, I32 maxsarg)
550 {
551     register SV *sv;
552     register I32 i;
553 
554     for (i = 1; i <= maxsarg; i++) {
555 	sv = NEWSV(0,0);
556 	sv_setsv(sv,sarg[i]);
557 	SSCHECK(3);
558 	SSPUSHPTR(sarg[i]);		/* remember the pointer */
559 	SSPUSHPTR(sv);			/* remember the value */
560 	SSPUSHINT(SAVEt_ITEM);
561     }
562 }
563 
564 void
565 Perl_save_destructor(pTHX_ DESTRUCTORFUNC_NOCONTEXT_t f, void* p)
566 {
567     SSCHECK(3);
568     SSPUSHDPTR(f);
569     SSPUSHPTR(p);
570     SSPUSHINT(SAVEt_DESTRUCTOR);
571 }
572 
573 void
574 Perl_save_destructor_x(pTHX_ DESTRUCTORFUNC_t f, void* p)
575 {
576     SSCHECK(3);
577     SSPUSHDXPTR(f);
578     SSPUSHPTR(p);
579     SSPUSHINT(SAVEt_DESTRUCTOR_X);
580 }
581 
582 void
583 Perl_save_aelem(pTHX_ AV *av, I32 idx, SV **sptr)
584 {
585     SSCHECK(4);
586     SSPUSHPTR(SvREFCNT_inc(av));
587     SSPUSHINT(idx);
588     SSPUSHPTR(SvREFCNT_inc(*sptr));
589     SSPUSHINT(SAVEt_AELEM);
590     save_scalar_at(sptr);
591 }
592 
593 void
594 Perl_save_helem(pTHX_ HV *hv, SV *key, SV **sptr)
595 {
596     SSCHECK(4);
597     SSPUSHPTR(SvREFCNT_inc(hv));
598     SSPUSHPTR(SvREFCNT_inc(key));
599     SSPUSHPTR(SvREFCNT_inc(*sptr));
600     SSPUSHINT(SAVEt_HELEM);
601     save_scalar_at(sptr);
602 }
603 
604 void
605 Perl_save_op(pTHX)
606 {
607     SSCHECK(2);
608     SSPUSHPTR(PL_op);
609     SSPUSHINT(SAVEt_OP);
610 }
611 
612 I32
613 Perl_save_alloc(pTHX_ I32 size, I32 pad)
614 {
615     register I32 start = pad + ((char*)&PL_savestack[PL_savestack_ix]
616                                 - (char*)PL_savestack);
617     register I32 elems = 1 + ((size + pad - 1) / sizeof(*PL_savestack));
618 
619     /* SSCHECK may not be good enough */
620     while (PL_savestack_ix + elems + 2 > PL_savestack_max)
621         savestack_grow();
622 
623     PL_savestack_ix += elems;
624     SSPUSHINT(elems);
625     SSPUSHINT(SAVEt_ALLOC);
626     return start;
627 }
628 
629 void
630 Perl_leave_scope(pTHX_ I32 base)
631 {
632     register SV *sv;
633     register SV *value;
634     register GV *gv;
635     register AV *av;
636     register HV *hv;
637     register void* ptr;
638     register char* str;
639     I32 i;
640 
641     if (base < -1)
642 	Perl_croak(aTHX_ "panic: corrupt saved stack index");
643     while (PL_savestack_ix > base) {
644 	switch (SSPOPINT) {
645 	case SAVEt_ITEM:			/* normal string */
646 	    value = (SV*)SSPOPPTR;
647 	    sv = (SV*)SSPOPPTR;
648 	    sv_replace(sv,value);
649 	    PL_localizing = 2;
650 	    SvSETMAGIC(sv);
651 	    PL_localizing = 0;
652 	    break;
653         case SAVEt_SV:				/* scalar reference */
654 	    value = (SV*)SSPOPPTR;
655 	    gv = (GV*)SSPOPPTR;
656 	    ptr = &GvSV(gv);
657 	    SvREFCNT_dec(gv);
658 	    goto restore_sv;
659         case SAVEt_GENERIC_PVREF:		/* generic pv */
660 	    str = (char*)SSPOPPTR;
661 	    ptr = SSPOPPTR;
662 	    if (*(char**)ptr != str) {
663 		Safefree(*(char**)ptr);
664 		*(char**)ptr = str;
665 	    }
666 	    break;
667         case SAVEt_GENERIC_SVREF:		/* generic sv */
668 	    value = (SV*)SSPOPPTR;
669 	    ptr = SSPOPPTR;
670 	    sv = *(SV**)ptr;
671 	    *(SV**)ptr = value;
672 	    SvREFCNT_dec(sv);
673 	    SvREFCNT_dec(value);
674 	    break;
675         case SAVEt_SVREF:			/* scalar reference */
676 	    value = (SV*)SSPOPPTR;
677 	    ptr = SSPOPPTR;
678 	restore_sv:
679 	    sv = *(SV**)ptr;
680 	    DEBUG_S(PerlIO_printf(Perl_debug_log,
681 				  "restore svref: %p %p:%s -> %p:%s\n",
682 			  	  ptr, sv, SvPEEK(sv), value, SvPEEK(value)));
683 	    if (SvTYPE(sv) >= SVt_PVMG && SvMAGIC(sv) &&
684 		SvTYPE(sv) != SVt_PVGV)
685 	    {
686 		(void)SvUPGRADE(value, SvTYPE(sv));
687 		SvMAGIC(value) = SvMAGIC(sv);
688 		SvFLAGS(value) |= SvMAGICAL(sv);
689 		SvMAGICAL_off(sv);
690 		SvMAGIC(sv) = 0;
691 	    }
692 	    /* XXX This branch is pretty bogus.  This code irretrievably
693 	     * clears(!) the magic on the SV (either to avoid further
694 	     * croaking that might ensue when the SvSETMAGIC() below is
695 	     * called, or to avoid two different SVs pointing at the same
696 	     * SvMAGIC()).  This needs a total rethink.  --GSAR */
697 	    else if (SvTYPE(value) >= SVt_PVMG && SvMAGIC(value) &&
698 		     SvTYPE(value) != SVt_PVGV)
699 	    {
700 		SvFLAGS(value) |= (SvFLAGS(value) &
701 				   (SVp_IOK|SVp_NOK|SVp_POK)) >> PRIVSHIFT;
702 		SvMAGICAL_off(value);
703 		/* XXX this is a leak when we get here because the
704 		 * mg_get() in save_scalar_at() croaked */
705 		SvMAGIC(value) = 0;
706 	    }
707             SvREFCNT_dec(sv);
708 	    *(SV**)ptr = value;
709 	    PL_localizing = 2;
710 	    SvSETMAGIC(value);
711 	    PL_localizing = 0;
712 	    SvREFCNT_dec(value);
713             break;
714         case SAVEt_AV:				/* array reference */
715 	    av = (AV*)SSPOPPTR;
716 	    gv = (GV*)SSPOPPTR;
717 	    if (GvAV(gv)) {
718 		AV *goner = GvAV(gv);
719 		SvMAGIC(av) = SvMAGIC(goner);
720 		SvFLAGS((SV*)av) |= SvMAGICAL(goner);
721 		SvMAGICAL_off(goner);
722 		SvMAGIC(goner) = 0;
723 		SvREFCNT_dec(goner);
724 	    }
725             GvAV(gv) = av;
726 	    if (SvMAGICAL(av)) {
727 		PL_localizing = 2;
728 		SvSETMAGIC((SV*)av);
729 		PL_localizing = 0;
730 	    }
731             break;
732         case SAVEt_HV:				/* hash reference */
733 	    hv = (HV*)SSPOPPTR;
734 	    gv = (GV*)SSPOPPTR;
735 	    if (GvHV(gv)) {
736 		HV *goner = GvHV(gv);
737 		SvMAGIC(hv) = SvMAGIC(goner);
738 		SvFLAGS(hv) |= SvMAGICAL(goner);
739 		SvMAGICAL_off(goner);
740 		SvMAGIC(goner) = 0;
741 		SvREFCNT_dec(goner);
742 	    }
743             GvHV(gv) = hv;
744 	    if (SvMAGICAL(hv)) {
745 		PL_localizing = 2;
746 		SvSETMAGIC((SV*)hv);
747 		PL_localizing = 0;
748 	    }
749             break;
750 	case SAVEt_INT:				/* int reference */
751 	    ptr = SSPOPPTR;
752 	    *(int*)ptr = (int)SSPOPINT;
753 	    break;
754 	case SAVEt_LONG:			/* long reference */
755 	    ptr = SSPOPPTR;
756 	    *(long*)ptr = (long)SSPOPLONG;
757 	    break;
758 	case SAVEt_I32:				/* I32 reference */
759 	    ptr = SSPOPPTR;
760 	    *(I32*)ptr = (I32)SSPOPINT;
761 	    break;
762 	case SAVEt_I16:				/* I16 reference */
763 	    ptr = SSPOPPTR;
764 	    *(I16*)ptr = (I16)SSPOPINT;
765 	    break;
766 	case SAVEt_I8:				/* I8 reference */
767 	    ptr = SSPOPPTR;
768 	    *(I8*)ptr = (I8)SSPOPINT;
769 	    break;
770 	case SAVEt_IV:				/* IV reference */
771 	    ptr = SSPOPPTR;
772 	    *(IV*)ptr = (IV)SSPOPIV;
773 	    break;
774 	case SAVEt_SPTR:			/* SV* reference */
775 	    ptr = SSPOPPTR;
776 	    *(SV**)ptr = (SV*)SSPOPPTR;
777 	    break;
778 	case SAVEt_VPTR:			/* random* reference */
779 	case SAVEt_PPTR:			/* char* reference */
780 	    ptr = SSPOPPTR;
781 	    *(char**)ptr = (char*)SSPOPPTR;
782 	    break;
783 	case SAVEt_HPTR:			/* HV* reference */
784 	    ptr = SSPOPPTR;
785 	    *(HV**)ptr = (HV*)SSPOPPTR;
786 	    break;
787 	case SAVEt_APTR:			/* AV* reference */
788 	    ptr = SSPOPPTR;
789 	    *(AV**)ptr = (AV*)SSPOPPTR;
790 	    break;
791 	case SAVEt_NSTAB:
792 	    gv = (GV*)SSPOPPTR;
793 	    (void)sv_clear((SV*)gv);
794 	    break;
795 	case SAVEt_GP:				/* scalar reference */
796 	    ptr = SSPOPPTR;
797 	    gv = (GV*)SSPOPPTR;
798             if (SvPVX(gv) && SvLEN(gv) > 0) {
799                 Safefree(SvPVX(gv));
800             }
801             SvPVX(gv) = (char *)SSPOPPTR;
802             SvCUR(gv) = (STRLEN)SSPOPIV;
803             SvLEN(gv) = (STRLEN)SSPOPIV;
804             gp_free(gv);
805             GvGP(gv) = (GP*)ptr;
806 	    if (GvCVu(gv))
807 		PL_sub_generation++;  /* putting a method back into circulation */
808 	    SvREFCNT_dec(gv);
809             break;
810 	case SAVEt_FREESV:
811 	    ptr = SSPOPPTR;
812 	    SvREFCNT_dec((SV*)ptr);
813 	    break;
814 	case SAVEt_MORTALIZESV:
815 	    ptr = SSPOPPTR;
816 	    sv_2mortal((SV*)ptr);
817 	    break;
818 	case SAVEt_FREEOP:
819 	    ptr = SSPOPPTR;
820 	    if (PL_comppad)
821 		PL_curpad = AvARRAY(PL_comppad);
822 	    op_free((OP*)ptr);
823 	    break;
824 	case SAVEt_FREEPV:
825 	    ptr = SSPOPPTR;
826 	    Safefree((char*)ptr);
827 	    break;
828 	case SAVEt_CLEARSV:
829 	    ptr = (void*)&PL_curpad[SSPOPLONG];
830 	    sv = *(SV**)ptr;
831 	    /* Can clear pad variable in place? */
832 	    if (SvREFCNT(sv) <= 1 && !SvOBJECT(sv)) {
833 		if (SvTHINKFIRST(sv))
834 		    sv_force_normal(sv);
835 		if (SvMAGICAL(sv))
836 		    mg_free(sv);
837 
838 		switch (SvTYPE(sv)) {
839 		case SVt_NULL:
840 		    break;
841 		case SVt_PVAV:
842 		    av_clear((AV*)sv);
843 		    break;
844 		case SVt_PVHV:
845 		    hv_clear((HV*)sv);
846 		    break;
847 		case SVt_PVCV:
848 		    Perl_croak(aTHX_ "panic: leave_scope pad code");
849 		case SVt_RV:
850 		case SVt_IV:
851 		case SVt_NV:
852 		    (void)SvOK_off(sv);
853 		    break;
854 		default:
855 		    (void)SvOK_off(sv);
856 		    (void)SvOOK_off(sv);
857 		    break;
858 		}
859 	    }
860 	    else {	/* Someone has a claim on this, so abandon it. */
861 		U32 padflags = SvFLAGS(sv) & (SVs_PADBUSY|SVs_PADMY|SVs_PADTMP);
862 		switch (SvTYPE(sv)) {	/* Console ourselves with a new value */
863 		case SVt_PVAV:	*(SV**)ptr = (SV*)newAV();	break;
864 		case SVt_PVHV:	*(SV**)ptr = (SV*)newHV();	break;
865 		default:	*(SV**)ptr = NEWSV(0,0);	break;
866 		}
867 		SvREFCNT_dec(sv);	/* Cast current value to the winds. */
868 		SvFLAGS(*(SV**)ptr) |= padflags; /* preserve pad nature */
869 	    }
870 	    break;
871 	case SAVEt_DELETE:
872 	    ptr = SSPOPPTR;
873 	    hv = (HV*)ptr;
874 	    ptr = SSPOPPTR;
875 	    (void)hv_delete(hv, (char*)ptr, (U32)SSPOPINT, G_DISCARD);
876 	    SvREFCNT_dec(hv);
877 	    Safefree(ptr);
878 	    break;
879 	case SAVEt_DESTRUCTOR:
880 	    ptr = SSPOPPTR;
881 	    (*SSPOPDPTR)(ptr);
882 	    break;
883 	case SAVEt_DESTRUCTOR_X:
884 	    ptr = SSPOPPTR;
885 	    (*SSPOPDXPTR)(aTHXo_ ptr);
886 	    break;
887 	case SAVEt_REGCONTEXT:
888 	case SAVEt_ALLOC:
889 	    i = SSPOPINT;
890 	    PL_savestack_ix -= i;  	/* regexp must have croaked */
891 	    break;
892 	case SAVEt_STACK_POS:		/* Position on Perl stack */
893 	    i = SSPOPINT;
894 	    PL_stack_sp = PL_stack_base + i;
895 	    break;
896 	case SAVEt_AELEM:		/* array element */
897 	    value = (SV*)SSPOPPTR;
898 	    i = SSPOPINT;
899 	    av = (AV*)SSPOPPTR;
900 	    ptr = av_fetch(av,i,1);
901 	    if (ptr) {
902 		sv = *(SV**)ptr;
903 		if (sv && sv != &PL_sv_undef) {
904 		    if (SvTIED_mg((SV*)av, 'P'))
905 			(void)SvREFCNT_inc(sv);
906 		    SvREFCNT_dec(av);
907 		    goto restore_sv;
908 		}
909 	    }
910 	    SvREFCNT_dec(av);
911 	    SvREFCNT_dec(value);
912 	    break;
913 	case SAVEt_HELEM:		/* hash element */
914 	    value = (SV*)SSPOPPTR;
915 	    sv = (SV*)SSPOPPTR;
916 	    hv = (HV*)SSPOPPTR;
917 	    ptr = hv_fetch_ent(hv, sv, 1, 0);
918 	    if (ptr) {
919 		SV *oval = HeVAL((HE*)ptr);
920 		if (oval && oval != &PL_sv_undef) {
921 		    ptr = &HeVAL((HE*)ptr);
922 		    if (SvTIED_mg((SV*)hv, 'P'))
923 			(void)SvREFCNT_inc(*(SV**)ptr);
924 		    SvREFCNT_dec(hv);
925 		    SvREFCNT_dec(sv);
926 		    goto restore_sv;
927 		}
928 	    }
929 	    SvREFCNT_dec(hv);
930 	    SvREFCNT_dec(sv);
931 	    SvREFCNT_dec(value);
932 	    break;
933 	case SAVEt_OP:
934 	    PL_op = (OP*)SSPOPPTR;
935 	    break;
936 	case SAVEt_HINTS:
937 	    *(I32*)&PL_hints = (I32)SSPOPINT;
938 	    break;
939 	case SAVEt_COMPPAD:
940 	    PL_comppad = (AV*)SSPOPPTR;
941 	    if (PL_comppad)
942 		PL_curpad = AvARRAY(PL_comppad);
943 	    else
944 		PL_curpad = Null(SV**);
945 	    break;
946 	case SAVEt_PADSV:
947 	    {
948 		PADOFFSET off = (PADOFFSET)SSPOPLONG;
949 		ptr = SSPOPPTR;
950 		if (ptr)
951 		    ((SV**)ptr)[off] = (SV*)SSPOPPTR;
952 	    }
953 	    break;
954 	default:
955 	    Perl_croak(aTHX_ "panic: leave_scope inconsistency");
956 	}
957     }
958 }
959 
960 void
961 Perl_cx_dump(pTHX_ PERL_CONTEXT *cx)
962 {
963 #ifdef DEBUGGING
964     PerlIO_printf(Perl_debug_log, "CX %ld = %s\n", (long)(cx - cxstack), PL_block_type[CxTYPE(cx)]);
965     if (CxTYPE(cx) != CXt_SUBST) {
966 	PerlIO_printf(Perl_debug_log, "BLK_OLDSP = %ld\n", (long)cx->blk_oldsp);
967 	PerlIO_printf(Perl_debug_log, "BLK_OLDCOP = 0x%"UVxf"\n",
968 		      PTR2UV(cx->blk_oldcop));
969 	PerlIO_printf(Perl_debug_log, "BLK_OLDMARKSP = %ld\n", (long)cx->blk_oldmarksp);
970 	PerlIO_printf(Perl_debug_log, "BLK_OLDSCOPESP = %ld\n", (long)cx->blk_oldscopesp);
971 	PerlIO_printf(Perl_debug_log, "BLK_OLDRETSP = %ld\n", (long)cx->blk_oldretsp);
972 	PerlIO_printf(Perl_debug_log, "BLK_OLDPM = 0x%"UVxf"\n",
973 		      PTR2UV(cx->blk_oldpm));
974 	PerlIO_printf(Perl_debug_log, "BLK_GIMME = %s\n", cx->blk_gimme ? "LIST" : "SCALAR");
975     }
976     switch (CxTYPE(cx)) {
977     case CXt_NULL:
978     case CXt_BLOCK:
979 	break;
980     case CXt_FORMAT:
981 	PerlIO_printf(Perl_debug_log, "BLK_SUB.CV = 0x%"UVxf"\n",
982 		PTR2UV(cx->blk_sub.cv));
983 	PerlIO_printf(Perl_debug_log, "BLK_SUB.GV = 0x%"UVxf"\n",
984 		PTR2UV(cx->blk_sub.gv));
985 	PerlIO_printf(Perl_debug_log, "BLK_SUB.DFOUTGV = 0x%"UVxf"\n",
986 		PTR2UV(cx->blk_sub.dfoutgv));
987 	PerlIO_printf(Perl_debug_log, "BLK_SUB.HASARGS = %d\n",
988 		(int)cx->blk_sub.hasargs);
989 	break;
990     case CXt_SUB:
991 	PerlIO_printf(Perl_debug_log, "BLK_SUB.CV = 0x%"UVxf"\n",
992 		PTR2UV(cx->blk_sub.cv));
993 	PerlIO_printf(Perl_debug_log, "BLK_SUB.OLDDEPTH = %ld\n",
994 		(long)cx->blk_sub.olddepth);
995 	PerlIO_printf(Perl_debug_log, "BLK_SUB.HASARGS = %d\n",
996 		(int)cx->blk_sub.hasargs);
997 	PerlIO_printf(Perl_debug_log, "BLK_SUB.LVAL = %d\n",
998 		(int)cx->blk_sub.lval);
999 	break;
1000     case CXt_EVAL:
1001 	PerlIO_printf(Perl_debug_log, "BLK_EVAL.OLD_IN_EVAL = %ld\n",
1002 		(long)cx->blk_eval.old_in_eval);
1003 	PerlIO_printf(Perl_debug_log, "BLK_EVAL.OLD_OP_TYPE = %s (%s)\n",
1004 		PL_op_name[cx->blk_eval.old_op_type],
1005 		PL_op_desc[cx->blk_eval.old_op_type]);
1006 	if (cx->blk_eval.old_namesv)
1007 	    PerlIO_printf(Perl_debug_log, "BLK_EVAL.OLD_NAME = %s\n",
1008 			  SvPVX(cx->blk_eval.old_namesv));
1009 	PerlIO_printf(Perl_debug_log, "BLK_EVAL.OLD_EVAL_ROOT = 0x%"UVxf"\n",
1010 		PTR2UV(cx->blk_eval.old_eval_root));
1011 	break;
1012 
1013     case CXt_LOOP:
1014 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.LABEL = %s\n",
1015 		cx->blk_loop.label);
1016 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.RESETSP = %ld\n",
1017 		(long)cx->blk_loop.resetsp);
1018 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.REDO_OP = 0x%"UVxf"\n",
1019 		PTR2UV(cx->blk_loop.redo_op));
1020 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.NEXT_OP = 0x%"UVxf"\n",
1021 		PTR2UV(cx->blk_loop.next_op));
1022 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.LAST_OP = 0x%"UVxf"\n",
1023 		PTR2UV(cx->blk_loop.last_op));
1024 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.ITERIX = %ld\n",
1025 		(long)cx->blk_loop.iterix);
1026 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.ITERARY = 0x%"UVxf"\n",
1027 		PTR2UV(cx->blk_loop.iterary));
1028 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.ITERVAR = 0x%"UVxf"\n",
1029 		PTR2UV(CxITERVAR(cx)));
1030 	if (CxITERVAR(cx))
1031 	    PerlIO_printf(Perl_debug_log, "BLK_LOOP.ITERSAVE = 0x%"UVxf"\n",
1032 		PTR2UV(cx->blk_loop.itersave));
1033 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.ITERLVAL = 0x%"UVxf"\n",
1034 		PTR2UV(cx->blk_loop.iterlval));
1035 	break;
1036 
1037     case CXt_SUBST:
1038 	PerlIO_printf(Perl_debug_log, "SB_ITERS = %ld\n",
1039 		(long)cx->sb_iters);
1040 	PerlIO_printf(Perl_debug_log, "SB_MAXITERS = %ld\n",
1041 		(long)cx->sb_maxiters);
1042 	PerlIO_printf(Perl_debug_log, "SB_RFLAGS = %ld\n",
1043 		(long)cx->sb_rflags);
1044 	PerlIO_printf(Perl_debug_log, "SB_ONCE = %ld\n",
1045 		(long)cx->sb_once);
1046 	PerlIO_printf(Perl_debug_log, "SB_ORIG = %s\n",
1047 		cx->sb_orig);
1048 	PerlIO_printf(Perl_debug_log, "SB_DSTR = 0x%"UVxf"\n",
1049 		PTR2UV(cx->sb_dstr));
1050 	PerlIO_printf(Perl_debug_log, "SB_TARG = 0x%"UVxf"\n",
1051 		PTR2UV(cx->sb_targ));
1052 	PerlIO_printf(Perl_debug_log, "SB_S = 0x%"UVxf"\n",
1053 		PTR2UV(cx->sb_s));
1054 	PerlIO_printf(Perl_debug_log, "SB_M = 0x%"UVxf"\n",
1055 		PTR2UV(cx->sb_m));
1056 	PerlIO_printf(Perl_debug_log, "SB_STREND = 0x%"UVxf"\n",
1057 		PTR2UV(cx->sb_strend));
1058 	PerlIO_printf(Perl_debug_log, "SB_RXRES = 0x%"UVxf"\n",
1059 		PTR2UV(cx->sb_rxres));
1060 	break;
1061     }
1062 #endif	/* DEBUGGING */
1063 }
1064