xref: /openbsd-src/gnu/usr.bin/perl/scope.c (revision db3296cf5c1dd9058ceecc3a29fe4aaa0bd26000)
1 /*    scope.c
2  *
3  *    Copyright (c) 1991-2002, 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     PL_stack_sp = sp;
54 #ifndef STRESS_REALLOC
55     av_extend(PL_curstack, (p - PL_stack_base) + (n) + 128);
56 #else
57     av_extend(PL_curstack, (p - PL_stack_base) + (n) + 1);
58 #endif
59     return PL_stack_sp;
60 }
61 
62 #ifndef STRESS_REALLOC
63 #define GROW(old) ((old) * 3 / 2)
64 #else
65 #define GROW(old) ((old) + 1)
66 #endif
67 
68 PERL_SI *
69 Perl_new_stackinfo(pTHX_ I32 stitems, I32 cxitems)
70 {
71     PERL_SI *si;
72     New(56, si, 1, PERL_SI);
73     si->si_stack = newAV();
74     AvREAL_off(si->si_stack);
75     av_extend(si->si_stack, stitems > 0 ? stitems-1 : 0);
76     AvALLOC(si->si_stack)[0] = &PL_sv_undef;
77     AvFILLp(si->si_stack) = 0;
78     si->si_prev = 0;
79     si->si_next = 0;
80     si->si_cxmax = cxitems - 1;
81     si->si_cxix = -1;
82     si->si_type = PERLSI_UNDEF;
83     New(56, si->si_cxstack, cxitems, PERL_CONTEXT);
84     /* Without any kind of initialising PUSHSUBST()
85      * in pp_subst() will read uninitialised heap. */
86     Poison(si->si_cxstack, cxitems, PERL_CONTEXT);
87     return si;
88 }
89 
90 I32
91 Perl_cxinc(pTHX)
92 {
93     IV old_max = cxstack_max;
94     cxstack_max = GROW(cxstack_max);
95     Renew(cxstack, cxstack_max + 1, PERL_CONTEXT);	/* XXX should fix CXINC macro */
96     /* Without any kind of initialising deep enough recursion
97      * will end up reading uninitialised PERL_CONTEXTs. */
98     Poison(cxstack + old_max + 1, cxstack_max - old_max, PERL_CONTEXT);
99     return cxstack_ix + 1;
100 }
101 
102 void
103 Perl_push_return(pTHX_ OP *retop)
104 {
105     if (PL_retstack_ix == PL_retstack_max) {
106 	PL_retstack_max = GROW(PL_retstack_max);
107 	Renew(PL_retstack, PL_retstack_max, OP*);
108     }
109     PL_retstack[PL_retstack_ix++] = retop;
110 }
111 
112 OP *
113 Perl_pop_return(pTHX)
114 {
115     if (PL_retstack_ix > 0)
116 	return PL_retstack[--PL_retstack_ix];
117     else
118 	return Nullop;
119 }
120 
121 void
122 Perl_push_scope(pTHX)
123 {
124     if (PL_scopestack_ix == PL_scopestack_max) {
125 	PL_scopestack_max = GROW(PL_scopestack_max);
126 	Renew(PL_scopestack, PL_scopestack_max, I32);
127     }
128     PL_scopestack[PL_scopestack_ix++] = PL_savestack_ix;
129 
130 }
131 
132 void
133 Perl_pop_scope(pTHX)
134 {
135     I32 oldsave = PL_scopestack[--PL_scopestack_ix];
136     LEAVE_SCOPE(oldsave);
137 }
138 
139 void
140 Perl_markstack_grow(pTHX)
141 {
142     I32 oldmax = PL_markstack_max - PL_markstack;
143     I32 newmax = GROW(oldmax);
144 
145     Renew(PL_markstack, newmax, I32);
146     PL_markstack_ptr = PL_markstack + oldmax;
147     PL_markstack_max = PL_markstack + newmax;
148 }
149 
150 void
151 Perl_savestack_grow(pTHX)
152 {
153     PL_savestack_max = GROW(PL_savestack_max) + 4;
154     Renew(PL_savestack, PL_savestack_max, ANY);
155 }
156 
157 #undef GROW
158 
159 void
160 Perl_tmps_grow(pTHX_ I32 n)
161 {
162 #ifndef STRESS_REALLOC
163     if (n < 128)
164 	n = (PL_tmps_max < 512) ? 128 : 512;
165 #endif
166     PL_tmps_max = PL_tmps_ix + n + 1;
167     Renew(PL_tmps_stack, PL_tmps_max, SV*);
168 }
169 
170 
171 void
172 Perl_free_tmps(pTHX)
173 {
174     /* XXX should tmps_floor live in cxstack? */
175     I32 myfloor = PL_tmps_floor;
176     while (PL_tmps_ix > myfloor) {      /* clean up after last statement */
177 	SV* sv = PL_tmps_stack[PL_tmps_ix];
178 	PL_tmps_stack[PL_tmps_ix--] = Nullsv;
179 	if (sv && sv != &PL_sv_undef) {
180 	    SvTEMP_off(sv);
181 	    SvREFCNT_dec(sv);		/* note, can modify tmps_ix!!! */
182 	}
183     }
184 }
185 
186 STATIC SV *
187 S_save_scalar_at(pTHX_ SV **sptr)
188 {
189     register SV *sv;
190     SV *osv = *sptr;
191 
192     sv = *sptr = NEWSV(0,0);
193     if (SvTYPE(osv) >= SVt_PVMG && SvMAGIC(osv) && SvTYPE(osv) != SVt_PVGV) {
194 	sv_upgrade(sv, SvTYPE(osv));
195 	if (SvGMAGICAL(osv)) {
196 	    MAGIC* mg;
197 	    bool oldtainted = PL_tainted;
198 	    mg_get(osv);		/* note, can croak! */
199 	    if (PL_tainting && PL_tainted &&
200 			(mg = mg_find(osv, PERL_MAGIC_taint))) {
201 		SAVESPTR(mg->mg_obj);
202 		mg->mg_obj = osv;
203 	    }
204 	    SvFLAGS(osv) |= (SvFLAGS(osv) &
205 	       (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 /* Like save_generic_pvref(), but uses PerlMemShared_free() rather than Safefree().
265  * Can be used to restore a shared global char* to its prior
266  * contents, freeing new value. */
267 void
268 Perl_save_shared_pvref(pTHX_ char **str)
269 {
270     SSCHECK(3);
271     SSPUSHPTR(str);
272     SSPUSHPTR(*str);
273     SSPUSHINT(SAVEt_SHARED_PVREF);
274 }
275 
276 void
277 Perl_save_gp(pTHX_ GV *gv, I32 empty)
278 {
279     SSCHECK(6);
280     SSPUSHIV((IV)SvLEN(gv));
281     SvLEN(gv) = 0; /* forget that anything was allocated here */
282     SSPUSHIV((IV)SvCUR(gv));
283     SSPUSHPTR(SvPVX(gv));
284     SvPOK_off(gv);
285     SSPUSHPTR(SvREFCNT_inc(gv));
286     SSPUSHPTR(GvGP(gv));
287     SSPUSHINT(SAVEt_GP);
288 
289     if (empty) {
290 	register GP *gp;
291 
292 	Newz(602, gp, 1, GP);
293 
294 	if (GvCVu(gv))
295 	    PL_sub_generation++;	/* taking a method out of circulation */
296 	if (GvIOp(gv) && (IoFLAGS(GvIOp(gv)) & IOf_ARGV)) {
297 	    gp->gp_io = newIO();
298 	    IoFLAGS(gp->gp_io) |= IOf_ARGV|IOf_START;
299 	}
300 	GvGP(gv) = gp_ref(gp);
301 	GvSV(gv) = NEWSV(72,0);
302 	GvLINE(gv) = CopLINE(PL_curcop);
303 	GvFILE(gv) = CopFILE(PL_curcop) ? CopFILE(PL_curcop) : "";
304 	GvEGV(gv) = gv;
305     }
306     else {
307 	gp_ref(GvGP(gv));
308 	GvINTRO_on(gv);
309     }
310 }
311 
312 AV *
313 Perl_save_ary(pTHX_ GV *gv)
314 {
315     AV *oav = GvAVn(gv);
316     AV *av;
317 
318     if (!AvREAL(oav) && AvREIFY(oav))
319 	av_reify(oav);
320     SSCHECK(3);
321     SSPUSHPTR(gv);
322     SSPUSHPTR(oav);
323     SSPUSHINT(SAVEt_AV);
324 
325     GvAV(gv) = Null(AV*);
326     av = GvAVn(gv);
327     if (SvMAGIC(oav)) {
328 	SvMAGIC(av) = SvMAGIC(oav);
329 	SvFLAGS((SV*)av) |= SvMAGICAL(oav);
330 	SvMAGICAL_off(oav);
331 	SvMAGIC(oav) = 0;
332 	PL_localizing = 1;
333 	SvSETMAGIC((SV*)av);
334 	PL_localizing = 0;
335     }
336     return av;
337 }
338 
339 HV *
340 Perl_save_hash(pTHX_ GV *gv)
341 {
342     HV *ohv, *hv;
343 
344     SSCHECK(3);
345     SSPUSHPTR(gv);
346     SSPUSHPTR(ohv = GvHVn(gv));
347     SSPUSHINT(SAVEt_HV);
348 
349     GvHV(gv) = Null(HV*);
350     hv = GvHVn(gv);
351     if (SvMAGIC(ohv)) {
352 	SvMAGIC(hv) = SvMAGIC(ohv);
353 	SvFLAGS((SV*)hv) |= SvMAGICAL(ohv);
354 	SvMAGICAL_off(ohv);
355 	SvMAGIC(ohv) = 0;
356 	PL_localizing = 1;
357 	SvSETMAGIC((SV*)hv);
358 	PL_localizing = 0;
359     }
360     return hv;
361 }
362 
363 void
364 Perl_save_item(pTHX_ register SV *item)
365 {
366     register SV *sv = NEWSV(0,0);
367 
368     sv_setsv(sv,item);
369     SSCHECK(3);
370     SSPUSHPTR(item);		/* remember the pointer */
371     SSPUSHPTR(sv);		/* remember the value */
372     SSPUSHINT(SAVEt_ITEM);
373 }
374 
375 void
376 Perl_save_int(pTHX_ int *intp)
377 {
378     SSCHECK(3);
379     SSPUSHINT(*intp);
380     SSPUSHPTR(intp);
381     SSPUSHINT(SAVEt_INT);
382 }
383 
384 void
385 Perl_save_long(pTHX_ long int *longp)
386 {
387     SSCHECK(3);
388     SSPUSHLONG(*longp);
389     SSPUSHPTR(longp);
390     SSPUSHINT(SAVEt_LONG);
391 }
392 
393 void
394 Perl_save_I32(pTHX_ I32 *intp)
395 {
396     SSCHECK(3);
397     SSPUSHINT(*intp);
398     SSPUSHPTR(intp);
399     SSPUSHINT(SAVEt_I32);
400 }
401 
402 void
403 Perl_save_I16(pTHX_ I16 *intp)
404 {
405     SSCHECK(3);
406     SSPUSHINT(*intp);
407     SSPUSHPTR(intp);
408     SSPUSHINT(SAVEt_I16);
409 }
410 
411 void
412 Perl_save_I8(pTHX_ I8 *bytep)
413 {
414     SSCHECK(3);
415     SSPUSHINT(*bytep);
416     SSPUSHPTR(bytep);
417     SSPUSHINT(SAVEt_I8);
418 }
419 
420 void
421 Perl_save_iv(pTHX_ IV *ivp)
422 {
423     SSCHECK(3);
424     SSPUSHIV(*ivp);
425     SSPUSHPTR(ivp);
426     SSPUSHINT(SAVEt_IV);
427 }
428 
429 /* Cannot use save_sptr() to store a char* since the SV** cast will
430  * force word-alignment and we'll miss the pointer.
431  */
432 void
433 Perl_save_pptr(pTHX_ char **pptr)
434 {
435     SSCHECK(3);
436     SSPUSHPTR(*pptr);
437     SSPUSHPTR(pptr);
438     SSPUSHINT(SAVEt_PPTR);
439 }
440 
441 void
442 Perl_save_vptr(pTHX_ void *ptr)
443 {
444     SSCHECK(3);
445     SSPUSHPTR(*(char**)ptr);
446     SSPUSHPTR(ptr);
447     SSPUSHINT(SAVEt_VPTR);
448 }
449 
450 void
451 Perl_save_sptr(pTHX_ SV **sptr)
452 {
453     SSCHECK(3);
454     SSPUSHPTR(*sptr);
455     SSPUSHPTR(sptr);
456     SSPUSHINT(SAVEt_SPTR);
457 }
458 
459 void
460 Perl_save_padsv(pTHX_ PADOFFSET off)
461 {
462     SSCHECK(4);
463     SSPUSHPTR(PL_curpad[off]);
464     SSPUSHPTR(PL_curpad);
465     SSPUSHLONG((long)off);
466     SSPUSHINT(SAVEt_PADSV);
467 }
468 
469 SV **
470 Perl_save_threadsv(pTHX_ PADOFFSET i)
471 {
472 #ifdef USE_5005THREADS
473     SV **svp = &THREADSV(i);	/* XXX Change to save by offset */
474     DEBUG_S(PerlIO_printf(Perl_debug_log, "save_threadsv %"UVuf": %p %p:%s\n",
475 			  (UV)i, svp, *svp, SvPEEK(*svp)));
476     save_svref(svp);
477     return svp;
478 #else
479     Perl_croak(aTHX_ "panic: save_threadsv called in non-threaded perl");
480     return 0;
481 #endif /* USE_5005THREADS */
482 }
483 
484 void
485 Perl_save_nogv(pTHX_ GV *gv)
486 {
487     SSCHECK(2);
488     SSPUSHPTR(gv);
489     SSPUSHINT(SAVEt_NSTAB);
490 }
491 
492 void
493 Perl_save_hptr(pTHX_ HV **hptr)
494 {
495     SSCHECK(3);
496     SSPUSHPTR(*hptr);
497     SSPUSHPTR(hptr);
498     SSPUSHINT(SAVEt_HPTR);
499 }
500 
501 void
502 Perl_save_aptr(pTHX_ AV **aptr)
503 {
504     SSCHECK(3);
505     SSPUSHPTR(*aptr);
506     SSPUSHPTR(aptr);
507     SSPUSHINT(SAVEt_APTR);
508 }
509 
510 void
511 Perl_save_freesv(pTHX_ SV *sv)
512 {
513     SSCHECK(2);
514     SSPUSHPTR(sv);
515     SSPUSHINT(SAVEt_FREESV);
516 }
517 
518 void
519 Perl_save_mortalizesv(pTHX_ SV *sv)
520 {
521     SSCHECK(2);
522     SSPUSHPTR(sv);
523     SSPUSHINT(SAVEt_MORTALIZESV);
524 }
525 
526 void
527 Perl_save_freeop(pTHX_ OP *o)
528 {
529     SSCHECK(2);
530     SSPUSHPTR(o);
531     SSPUSHINT(SAVEt_FREEOP);
532 }
533 
534 void
535 Perl_save_freepv(pTHX_ char *pv)
536 {
537     SSCHECK(2);
538     SSPUSHPTR(pv);
539     SSPUSHINT(SAVEt_FREEPV);
540 }
541 
542 void
543 Perl_save_clearsv(pTHX_ SV **svp)
544 {
545     SSCHECK(2);
546     SSPUSHLONG((long)(svp-PL_curpad));
547     SSPUSHINT(SAVEt_CLEARSV);
548 }
549 
550 void
551 Perl_save_delete(pTHX_ HV *hv, char *key, I32 klen)
552 {
553     SSCHECK(4);
554     SSPUSHINT(klen);
555     SSPUSHPTR(key);
556     SSPUSHPTR(SvREFCNT_inc(hv));
557     SSPUSHINT(SAVEt_DELETE);
558 }
559 
560 void
561 Perl_save_list(pTHX_ register SV **sarg, I32 maxsarg)
562 {
563     register SV *sv;
564     register I32 i;
565 
566     for (i = 1; i <= maxsarg; i++) {
567 	sv = NEWSV(0,0);
568 	sv_setsv(sv,sarg[i]);
569 	SSCHECK(3);
570 	SSPUSHPTR(sarg[i]);		/* remember the pointer */
571 	SSPUSHPTR(sv);			/* remember the value */
572 	SSPUSHINT(SAVEt_ITEM);
573     }
574 }
575 
576 void
577 Perl_save_destructor(pTHX_ DESTRUCTORFUNC_NOCONTEXT_t f, void* p)
578 {
579     SSCHECK(3);
580     SSPUSHDPTR(f);
581     SSPUSHPTR(p);
582     SSPUSHINT(SAVEt_DESTRUCTOR);
583 }
584 
585 void
586 Perl_save_destructor_x(pTHX_ DESTRUCTORFUNC_t f, void* p)
587 {
588     SSCHECK(3);
589     SSPUSHDXPTR(f);
590     SSPUSHPTR(p);
591     SSPUSHINT(SAVEt_DESTRUCTOR_X);
592 }
593 
594 void
595 Perl_save_aelem(pTHX_ AV *av, I32 idx, SV **sptr)
596 {
597     SV *sv;
598     SSCHECK(4);
599     SSPUSHPTR(SvREFCNT_inc(av));
600     SSPUSHINT(idx);
601     SSPUSHPTR(SvREFCNT_inc(*sptr));
602     SSPUSHINT(SAVEt_AELEM);
603     save_scalar_at(sptr);
604     sv = *sptr;
605     /* If we're localizing a tied array element, this new sv
606      * won't actually be stored in the array - so it won't get
607      * reaped when the localize ends. Ensure it gets reaped by
608      * mortifying it instead. DAPM */
609     if (SvTIED_mg(sv, PERL_MAGIC_tiedelem))
610 	sv_2mortal(sv);
611 }
612 
613 void
614 Perl_save_helem(pTHX_ HV *hv, SV *key, SV **sptr)
615 {
616     SV *sv;
617     SSCHECK(4);
618     SSPUSHPTR(SvREFCNT_inc(hv));
619     SSPUSHPTR(SvREFCNT_inc(key));
620     SSPUSHPTR(SvREFCNT_inc(*sptr));
621     SSPUSHINT(SAVEt_HELEM);
622     save_scalar_at(sptr);
623     sv = *sptr;
624     /* If we're localizing a tied hash element, this new sv
625      * won't actually be stored in the hash - so it won't get
626      * reaped when the localize ends. Ensure it gets reaped by
627      * mortifying it instead. DAPM */
628     if (SvTIED_mg(sv, PERL_MAGIC_tiedelem))
629 	sv_2mortal(sv);
630 }
631 
632 void
633 Perl_save_op(pTHX)
634 {
635     SSCHECK(2);
636     SSPUSHPTR(PL_op);
637     SSPUSHINT(SAVEt_OP);
638 }
639 
640 I32
641 Perl_save_alloc(pTHX_ I32 size, I32 pad)
642 {
643     register I32 start = pad + ((char*)&PL_savestack[PL_savestack_ix]
644 				- (char*)PL_savestack);
645     register I32 elems = 1 + ((size + pad - 1) / sizeof(*PL_savestack));
646 
647     /* SSCHECK may not be good enough */
648     while (PL_savestack_ix + elems + 2 > PL_savestack_max)
649 	savestack_grow();
650 
651     PL_savestack_ix += elems;
652     SSPUSHINT(elems);
653     SSPUSHINT(SAVEt_ALLOC);
654     return start;
655 }
656 
657 void
658 Perl_leave_scope(pTHX_ I32 base)
659 {
660     register SV *sv;
661     register SV *value;
662     register GV *gv;
663     register AV *av;
664     register HV *hv;
665     register void* ptr;
666     register char* str;
667     I32 i;
668 
669     if (base < -1)
670 	Perl_croak(aTHX_ "panic: corrupt saved stack index");
671     while (PL_savestack_ix > base) {
672 	switch (SSPOPINT) {
673 	case SAVEt_ITEM:			/* normal string */
674 	    value = (SV*)SSPOPPTR;
675 	    sv = (SV*)SSPOPPTR;
676 	    sv_replace(sv,value);
677 	    PL_localizing = 2;
678 	    SvSETMAGIC(sv);
679 	    PL_localizing = 0;
680 	    break;
681 	case SAVEt_SV:				/* scalar reference */
682 	    value = (SV*)SSPOPPTR;
683 	    gv = (GV*)SSPOPPTR;
684 	    ptr = &GvSV(gv);
685 	    SvREFCNT_dec(gv);
686 	    goto restore_sv;
687 	case SAVEt_GENERIC_PVREF:		/* generic pv */
688 	    str = (char*)SSPOPPTR;
689 	    ptr = SSPOPPTR;
690 	    if (*(char**)ptr != str) {
691 		Safefree(*(char**)ptr);
692 		*(char**)ptr = str;
693 	    }
694 	    break;
695 	case SAVEt_SHARED_PVREF:		/* shared pv */
696 	    str = (char*)SSPOPPTR;
697 	    ptr = SSPOPPTR;
698 	    if (*(char**)ptr != str) {
699 #ifdef NETWARE
700 		PerlMem_free(*(char**)ptr);
701 #else
702 		PerlMemShared_free(*(char**)ptr);
703 #endif
704 		*(char**)ptr = str;
705 	    }
706 	    break;
707 	case SAVEt_GENERIC_SVREF:		/* generic sv */
708 	    value = (SV*)SSPOPPTR;
709 	    ptr = SSPOPPTR;
710 	    sv = *(SV**)ptr;
711 	    *(SV**)ptr = value;
712 	    SvREFCNT_dec(sv);
713 	    SvREFCNT_dec(value);
714 	    break;
715 	case SAVEt_SVREF:			/* scalar reference */
716 	    value = (SV*)SSPOPPTR;
717 	    ptr = SSPOPPTR;
718 	restore_sv:
719 	    sv = *(SV**)ptr;
720 	    DEBUG_S(PerlIO_printf(Perl_debug_log,
721 				  "restore svref: %p %p:%s -> %p:%s\n",
722 				  ptr, sv, SvPEEK(sv), value, SvPEEK(value)));
723 	    if (SvTYPE(sv) >= SVt_PVMG && SvMAGIC(sv) &&
724 		SvTYPE(sv) != SVt_PVGV)
725 	    {
726 		(void)SvUPGRADE(value, SvTYPE(sv));
727 		SvMAGIC(value) = SvMAGIC(sv);
728 		SvFLAGS(value) |= SvMAGICAL(sv);
729 		SvMAGICAL_off(sv);
730 		SvMAGIC(sv) = 0;
731 	    }
732 	    /* XXX This branch is pretty bogus.  This code irretrievably
733 	     * clears(!) the magic on the SV (either to avoid further
734 	     * croaking that might ensue when the SvSETMAGIC() below is
735 	     * called, or to avoid two different SVs pointing at the same
736 	     * SvMAGIC()).  This needs a total rethink.  --GSAR */
737 	    else if (SvTYPE(value) >= SVt_PVMG && SvMAGIC(value) &&
738 		     SvTYPE(value) != SVt_PVGV)
739 	    {
740 		SvFLAGS(value) |= (SvFLAGS(value) &
741 				  (SVp_NOK|SVp_POK)) >> PRIVSHIFT;
742 		SvMAGICAL_off(value);
743 		/* XXX this is a leak when we get here because the
744 		 * mg_get() in save_scalar_at() croaked */
745 		SvMAGIC(value) = 0;
746 	    }
747 	    SvREFCNT_dec(sv);
748 	    *(SV**)ptr = value;
749 	    PL_localizing = 2;
750 	    SvSETMAGIC(value);
751 	    PL_localizing = 0;
752 	    SvREFCNT_dec(value);
753 	    break;
754 	case SAVEt_AV:				/* array reference */
755 	    av = (AV*)SSPOPPTR;
756 	    gv = (GV*)SSPOPPTR;
757 	    if (GvAV(gv)) {
758 		AV *goner = GvAV(gv);
759 		SvMAGIC(av) = SvMAGIC(goner);
760 		SvFLAGS((SV*)av) |= SvMAGICAL(goner);
761 		SvMAGICAL_off(goner);
762 		SvMAGIC(goner) = 0;
763 		SvREFCNT_dec(goner);
764 	    }
765 	    GvAV(gv) = av;
766 	    if (SvMAGICAL(av)) {
767 		PL_localizing = 2;
768 		SvSETMAGIC((SV*)av);
769 		PL_localizing = 0;
770 	    }
771 	    break;
772 	case SAVEt_HV:				/* hash reference */
773 	    hv = (HV*)SSPOPPTR;
774 	    gv = (GV*)SSPOPPTR;
775 	    if (GvHV(gv)) {
776 		HV *goner = GvHV(gv);
777 		SvMAGIC(hv) = SvMAGIC(goner);
778 		SvFLAGS(hv) |= SvMAGICAL(goner);
779 		SvMAGICAL_off(goner);
780 		SvMAGIC(goner) = 0;
781 		SvREFCNT_dec(goner);
782 	    }
783 	    GvHV(gv) = hv;
784 	    if (SvMAGICAL(hv)) {
785 		PL_localizing = 2;
786 		SvSETMAGIC((SV*)hv);
787 		PL_localizing = 0;
788 	    }
789 	    break;
790 	case SAVEt_INT:				/* int reference */
791 	    ptr = SSPOPPTR;
792 	    *(int*)ptr = (int)SSPOPINT;
793 	    break;
794 	case SAVEt_LONG:			/* long reference */
795 	    ptr = SSPOPPTR;
796 	    *(long*)ptr = (long)SSPOPLONG;
797 	    break;
798 	case SAVEt_I32:				/* I32 reference */
799 	    ptr = SSPOPPTR;
800 	    *(I32*)ptr = (I32)SSPOPINT;
801 	    break;
802 	case SAVEt_I16:				/* I16 reference */
803 	    ptr = SSPOPPTR;
804 	    *(I16*)ptr = (I16)SSPOPINT;
805 	    break;
806 	case SAVEt_I8:				/* I8 reference */
807 	    ptr = SSPOPPTR;
808 	    *(I8*)ptr = (I8)SSPOPINT;
809 	    break;
810 	case SAVEt_IV:				/* IV reference */
811 	    ptr = SSPOPPTR;
812 	    *(IV*)ptr = (IV)SSPOPIV;
813 	    break;
814 	case SAVEt_SPTR:			/* SV* reference */
815 	    ptr = SSPOPPTR;
816 	    *(SV**)ptr = (SV*)SSPOPPTR;
817 	    break;
818 	case SAVEt_VPTR:			/* random* reference */
819 	case SAVEt_PPTR:			/* char* reference */
820 	    ptr = SSPOPPTR;
821 	    *(char**)ptr = (char*)SSPOPPTR;
822 	    break;
823 	case SAVEt_HPTR:			/* HV* reference */
824 	    ptr = SSPOPPTR;
825 	    *(HV**)ptr = (HV*)SSPOPPTR;
826 	    break;
827 	case SAVEt_APTR:			/* AV* reference */
828 	    ptr = SSPOPPTR;
829 	    *(AV**)ptr = (AV*)SSPOPPTR;
830 	    break;
831 	case SAVEt_NSTAB:
832 	    gv = (GV*)SSPOPPTR;
833 	    (void)sv_clear((SV*)gv);
834 	    break;
835 	case SAVEt_GP:				/* scalar reference */
836 	    ptr = SSPOPPTR;
837 	    gv = (GV*)SSPOPPTR;
838 	    if (SvPVX(gv) && SvLEN(gv) > 0) {
839 		Safefree(SvPVX(gv));
840 	    }
841 	    SvPVX(gv) = (char *)SSPOPPTR;
842 	    SvCUR(gv) = (STRLEN)SSPOPIV;
843 	    SvLEN(gv) = (STRLEN)SSPOPIV;
844 	    gp_free(gv);
845 	    GvGP(gv) = (GP*)ptr;
846 	    if (GvCVu(gv))
847 		PL_sub_generation++;  /* putting a method back into circulation */
848 	    SvREFCNT_dec(gv);
849 	    break;
850 	case SAVEt_FREESV:
851 	    ptr = SSPOPPTR;
852 	    SvREFCNT_dec((SV*)ptr);
853 	    break;
854 	case SAVEt_MORTALIZESV:
855 	    ptr = SSPOPPTR;
856 	    sv_2mortal((SV*)ptr);
857 	    break;
858 	case SAVEt_FREEOP:
859 	    ptr = SSPOPPTR;
860 	    if (PL_comppad)
861 		PL_curpad = AvARRAY(PL_comppad);
862 	    op_free((OP*)ptr);
863 	    break;
864 	case SAVEt_FREEPV:
865 	    ptr = SSPOPPTR;
866 	    Safefree((char*)ptr);
867 	    break;
868 	case SAVEt_CLEARSV:
869 	    ptr = (void*)&PL_curpad[SSPOPLONG];
870 	    sv = *(SV**)ptr;
871 	    /* Can clear pad variable in place? */
872 	    if (SvREFCNT(sv) <= 1 && !SvOBJECT(sv)) {
873 		/*
874 		 * if a my variable that was made readonly is going out of
875 		 * scope, we want to remove the readonlyness so that it can
876 		 * go out of scope quietly
877 		 */
878 		if (SvPADMY(sv) && !SvFAKE(sv))
879 		    SvREADONLY_off(sv);
880 
881 		if (SvTHINKFIRST(sv))
882 		    sv_force_normal_flags(sv, SV_IMMEDIATE_UNREF);
883 		if (SvMAGICAL(sv))
884 		    mg_free(sv);
885 
886 		switch (SvTYPE(sv)) {
887 		case SVt_NULL:
888 		    break;
889 		case SVt_PVAV:
890 		    av_clear((AV*)sv);
891 		    break;
892 		case SVt_PVHV:
893 		    hv_clear((HV*)sv);
894 		    break;
895 		case SVt_PVCV:
896 		    Perl_croak(aTHX_ "panic: leave_scope pad code");
897 		case SVt_RV:
898 		case SVt_IV:
899 		case SVt_NV:
900 		    (void)SvOK_off(sv);
901 		    break;
902 		default:
903 		    (void)SvOK_off(sv);
904 		    (void)SvOOK_off(sv);
905 		    break;
906 		}
907 	    }
908 	    else {	/* Someone has a claim on this, so abandon it. */
909 		U32 padflags = SvFLAGS(sv) & (SVs_PADBUSY|SVs_PADMY|SVs_PADTMP);
910 		switch (SvTYPE(sv)) {	/* Console ourselves with a new value */
911 		case SVt_PVAV:	*(SV**)ptr = (SV*)newAV();	break;
912 		case SVt_PVHV:	*(SV**)ptr = (SV*)newHV();	break;
913 		default:	*(SV**)ptr = NEWSV(0,0);	break;
914 		}
915 		SvREFCNT_dec(sv);	/* Cast current value to the winds. */
916 		SvFLAGS(*(SV**)ptr) |= padflags; /* preserve pad nature */
917 	    }
918 	    break;
919 	case SAVEt_DELETE:
920 	    ptr = SSPOPPTR;
921 	    hv = (HV*)ptr;
922 	    ptr = SSPOPPTR;
923 	    (void)hv_delete(hv, (char*)ptr, (U32)SSPOPINT, G_DISCARD);
924 	    SvREFCNT_dec(hv);
925 	    Safefree(ptr);
926 	    break;
927 	case SAVEt_DESTRUCTOR:
928 	    ptr = SSPOPPTR;
929 	    (*SSPOPDPTR)(ptr);
930 	    break;
931 	case SAVEt_DESTRUCTOR_X:
932 	    ptr = SSPOPPTR;
933 	    (*SSPOPDXPTR)(aTHX_ ptr);
934 	    break;
935 	case SAVEt_REGCONTEXT:
936 	case SAVEt_ALLOC:
937 	    i = SSPOPINT;
938 	    PL_savestack_ix -= i;  	/* regexp must have croaked */
939 	    break;
940 	case SAVEt_STACK_POS:		/* Position on Perl stack */
941 	    i = SSPOPINT;
942 	    PL_stack_sp = PL_stack_base + i;
943 	    break;
944 	case SAVEt_AELEM:		/* array element */
945 	    value = (SV*)SSPOPPTR;
946 	    i = SSPOPINT;
947 	    av = (AV*)SSPOPPTR;
948 	    ptr = av_fetch(av,i,1);
949 	    if (ptr) {
950 		sv = *(SV**)ptr;
951 		if (sv && sv != &PL_sv_undef) {
952 		    if (SvTIED_mg((SV*)av, PERL_MAGIC_tied))
953 			(void)SvREFCNT_inc(sv);
954 		    SvREFCNT_dec(av);
955 		    goto restore_sv;
956 		}
957 	    }
958 	    SvREFCNT_dec(av);
959 	    SvREFCNT_dec(value);
960 	    break;
961 	case SAVEt_HELEM:		/* hash element */
962 	    value = (SV*)SSPOPPTR;
963 	    sv = (SV*)SSPOPPTR;
964 	    hv = (HV*)SSPOPPTR;
965 	    ptr = hv_fetch_ent(hv, sv, 1, 0);
966 	    if (ptr) {
967 		SV *oval = HeVAL((HE*)ptr);
968 		if (oval && oval != &PL_sv_undef) {
969 		    ptr = &HeVAL((HE*)ptr);
970 		    if (SvTIED_mg((SV*)hv, PERL_MAGIC_tied))
971 			(void)SvREFCNT_inc(*(SV**)ptr);
972 		    SvREFCNT_dec(hv);
973 		    SvREFCNT_dec(sv);
974 		    goto restore_sv;
975 		}
976 	    }
977 	    SvREFCNT_dec(hv);
978 	    SvREFCNT_dec(sv);
979 	    SvREFCNT_dec(value);
980 	    break;
981 	case SAVEt_OP:
982 	    PL_op = (OP*)SSPOPPTR;
983 	    break;
984 	case SAVEt_HINTS:
985 	    if ((PL_hints & HINT_LOCALIZE_HH) && GvHV(PL_hintgv)) {
986 		SvREFCNT_dec((SV*)GvHV(PL_hintgv));
987 		GvHV(PL_hintgv) = NULL;
988 	    }
989 	    *(I32*)&PL_hints = (I32)SSPOPINT;
990 	    break;
991 	case SAVEt_COMPPAD:
992 	    PL_comppad = (AV*)SSPOPPTR;
993 	    if (PL_comppad)
994 		PL_curpad = AvARRAY(PL_comppad);
995 	    else
996 		PL_curpad = Null(SV**);
997 	    break;
998 	case SAVEt_PADSV:
999 	    {
1000 		PADOFFSET off = (PADOFFSET)SSPOPLONG;
1001 		ptr = SSPOPPTR;
1002 		if (ptr)
1003 		    ((SV**)ptr)[off] = (SV*)SSPOPPTR;
1004 	    }
1005 	    break;
1006 	default:
1007 	    Perl_croak(aTHX_ "panic: leave_scope inconsistency");
1008 	}
1009     }
1010 }
1011 
1012 void
1013 Perl_cx_dump(pTHX_ PERL_CONTEXT *cx)
1014 {
1015 #ifdef DEBUGGING
1016     PerlIO_printf(Perl_debug_log, "CX %ld = %s\n", (long)(cx - cxstack), PL_block_type[CxTYPE(cx)]);
1017     if (CxTYPE(cx) != CXt_SUBST) {
1018 	PerlIO_printf(Perl_debug_log, "BLK_OLDSP = %ld\n", (long)cx->blk_oldsp);
1019 	PerlIO_printf(Perl_debug_log, "BLK_OLDCOP = 0x%"UVxf"\n",
1020 		      PTR2UV(cx->blk_oldcop));
1021 	PerlIO_printf(Perl_debug_log, "BLK_OLDMARKSP = %ld\n", (long)cx->blk_oldmarksp);
1022 	PerlIO_printf(Perl_debug_log, "BLK_OLDSCOPESP = %ld\n", (long)cx->blk_oldscopesp);
1023 	PerlIO_printf(Perl_debug_log, "BLK_OLDRETSP = %ld\n", (long)cx->blk_oldretsp);
1024 	PerlIO_printf(Perl_debug_log, "BLK_OLDPM = 0x%"UVxf"\n",
1025 		      PTR2UV(cx->blk_oldpm));
1026 	PerlIO_printf(Perl_debug_log, "BLK_GIMME = %s\n", cx->blk_gimme ? "LIST" : "SCALAR");
1027     }
1028     switch (CxTYPE(cx)) {
1029     case CXt_NULL:
1030     case CXt_BLOCK:
1031 	break;
1032     case CXt_FORMAT:
1033 	PerlIO_printf(Perl_debug_log, "BLK_SUB.CV = 0x%"UVxf"\n",
1034 		PTR2UV(cx->blk_sub.cv));
1035 	PerlIO_printf(Perl_debug_log, "BLK_SUB.GV = 0x%"UVxf"\n",
1036 		PTR2UV(cx->blk_sub.gv));
1037 	PerlIO_printf(Perl_debug_log, "BLK_SUB.DFOUTGV = 0x%"UVxf"\n",
1038 		PTR2UV(cx->blk_sub.dfoutgv));
1039 	PerlIO_printf(Perl_debug_log, "BLK_SUB.HASARGS = %d\n",
1040 		(int)cx->blk_sub.hasargs);
1041 	break;
1042     case CXt_SUB:
1043 	PerlIO_printf(Perl_debug_log, "BLK_SUB.CV = 0x%"UVxf"\n",
1044 		PTR2UV(cx->blk_sub.cv));
1045 	PerlIO_printf(Perl_debug_log, "BLK_SUB.OLDDEPTH = %ld\n",
1046 		(long)cx->blk_sub.olddepth);
1047 	PerlIO_printf(Perl_debug_log, "BLK_SUB.HASARGS = %d\n",
1048 		(int)cx->blk_sub.hasargs);
1049 	PerlIO_printf(Perl_debug_log, "BLK_SUB.LVAL = %d\n",
1050 		(int)cx->blk_sub.lval);
1051 	break;
1052     case CXt_EVAL:
1053 	PerlIO_printf(Perl_debug_log, "BLK_EVAL.OLD_IN_EVAL = %ld\n",
1054 		(long)cx->blk_eval.old_in_eval);
1055 	PerlIO_printf(Perl_debug_log, "BLK_EVAL.OLD_OP_TYPE = %s (%s)\n",
1056 		PL_op_name[cx->blk_eval.old_op_type],
1057 		PL_op_desc[cx->blk_eval.old_op_type]);
1058 	if (cx->blk_eval.old_namesv)
1059 	    PerlIO_printf(Perl_debug_log, "BLK_EVAL.OLD_NAME = %s\n",
1060 			  SvPVX(cx->blk_eval.old_namesv));
1061 	PerlIO_printf(Perl_debug_log, "BLK_EVAL.OLD_EVAL_ROOT = 0x%"UVxf"\n",
1062 		PTR2UV(cx->blk_eval.old_eval_root));
1063 	break;
1064 
1065     case CXt_LOOP:
1066 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.LABEL = %s\n",
1067 		cx->blk_loop.label);
1068 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.RESETSP = %ld\n",
1069 		(long)cx->blk_loop.resetsp);
1070 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.REDO_OP = 0x%"UVxf"\n",
1071 		PTR2UV(cx->blk_loop.redo_op));
1072 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.NEXT_OP = 0x%"UVxf"\n",
1073 		PTR2UV(cx->blk_loop.next_op));
1074 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.LAST_OP = 0x%"UVxf"\n",
1075 		PTR2UV(cx->blk_loop.last_op));
1076 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.ITERIX = %ld\n",
1077 		(long)cx->blk_loop.iterix);
1078 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.ITERARY = 0x%"UVxf"\n",
1079 		PTR2UV(cx->blk_loop.iterary));
1080 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.ITERVAR = 0x%"UVxf"\n",
1081 		PTR2UV(CxITERVAR(cx)));
1082 	if (CxITERVAR(cx))
1083 	    PerlIO_printf(Perl_debug_log, "BLK_LOOP.ITERSAVE = 0x%"UVxf"\n",
1084 		PTR2UV(cx->blk_loop.itersave));
1085 	PerlIO_printf(Perl_debug_log, "BLK_LOOP.ITERLVAL = 0x%"UVxf"\n",
1086 		PTR2UV(cx->blk_loop.iterlval));
1087 	break;
1088 
1089     case CXt_SUBST:
1090 	PerlIO_printf(Perl_debug_log, "SB_ITERS = %ld\n",
1091 		(long)cx->sb_iters);
1092 	PerlIO_printf(Perl_debug_log, "SB_MAXITERS = %ld\n",
1093 		(long)cx->sb_maxiters);
1094 	PerlIO_printf(Perl_debug_log, "SB_RFLAGS = %ld\n",
1095 		(long)cx->sb_rflags);
1096 	PerlIO_printf(Perl_debug_log, "SB_ONCE = %ld\n",
1097 		(long)cx->sb_once);
1098 	PerlIO_printf(Perl_debug_log, "SB_ORIG = %s\n",
1099 		cx->sb_orig);
1100 	PerlIO_printf(Perl_debug_log, "SB_DSTR = 0x%"UVxf"\n",
1101 		PTR2UV(cx->sb_dstr));
1102 	PerlIO_printf(Perl_debug_log, "SB_TARG = 0x%"UVxf"\n",
1103 		PTR2UV(cx->sb_targ));
1104 	PerlIO_printf(Perl_debug_log, "SB_S = 0x%"UVxf"\n",
1105 		PTR2UV(cx->sb_s));
1106 	PerlIO_printf(Perl_debug_log, "SB_M = 0x%"UVxf"\n",
1107 		PTR2UV(cx->sb_m));
1108 	PerlIO_printf(Perl_debug_log, "SB_STREND = 0x%"UVxf"\n",
1109 		PTR2UV(cx->sb_strend));
1110 	PerlIO_printf(Perl_debug_log, "SB_RXRES = 0x%"UVxf"\n",
1111 		PTR2UV(cx->sb_rxres));
1112 	break;
1113     }
1114 #endif	/* DEBUGGING */
1115 }
1116