xref: /openbsd-src/gnu/usr.bin/perl/cop.h (revision b2ea75c1b17e1a9a339660e7ed45cd24946b230e)
1 /*    cop.h
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 struct cop {
11     BASEOP
12     char *	cop_label;	/* label for this construct */
13 #ifdef USE_ITHREADS
14     char *	cop_stashpv;	/* package line was compiled in */
15     char *	cop_file;	/* file name the following line # is from */
16 #else
17     HV *	cop_stash;	/* package line was compiled in */
18     GV *	cop_filegv;	/* file the following line # is from */
19 #endif
20     U32		cop_seq;	/* parse sequence number */
21     I32		cop_arybase;	/* array base this line was compiled with */
22     line_t      cop_line;       /* line # of this command */
23     SV *	cop_warnings;	/* lexical warnings bitmask */
24 };
25 
26 #define Nullcop Null(COP*)
27 
28 #ifdef USE_ITHREADS
29 #  define CopFILE(c)		((c)->cop_file)
30 #  define CopFILEGV(c)		(CopFILE(c) \
31 				 ? gv_fetchfile(CopFILE(c)) : Nullgv)
32 #  define CopFILE_set(c,pv)	((c)->cop_file = savepv(pv))
33 #  define CopFILESV(c)		(CopFILE(c) \
34 				 ? GvSV(gv_fetchfile(CopFILE(c))) : Nullsv)
35 #  define CopFILEAV(c)		(CopFILE(c) \
36 				 ? GvAV(gv_fetchfile(CopFILE(c))) : Nullav)
37 #  define CopSTASHPV(c)		((c)->cop_stashpv)
38 #  define CopSTASHPV_set(c,pv)	((c)->cop_stashpv = ((pv) ? savepv(pv) : Nullch))
39 #  define CopSTASH(c)		(CopSTASHPV(c) \
40 				 ? gv_stashpv(CopSTASHPV(c),GV_ADD) : Nullhv)
41 #  define CopSTASH_set(c,hv)	CopSTASHPV_set(c, (hv) ? HvNAME(hv) : Nullch)
42 #  define CopSTASH_eq(c,hv)	((hv) 					\
43 				 && (CopSTASHPV(c) == HvNAME(hv)	\
44 				     || (CopSTASHPV(c) && HvNAME(hv)	\
45 					 && strEQ(CopSTASHPV(c), HvNAME(hv)))))
46 #else
47 #  define CopFILEGV(c)		((c)->cop_filegv)
48 #  define CopFILEGV_set(c,gv)	((c)->cop_filegv = (GV*)SvREFCNT_inc(gv))
49 #  define CopFILE_set(c,pv)	CopFILEGV_set((c), gv_fetchfile(pv))
50 #  define CopFILESV(c)		(CopFILEGV(c) ? GvSV(CopFILEGV(c)) : Nullsv)
51 #  define CopFILEAV(c)		(CopFILEGV(c) ? GvAV(CopFILEGV(c)) : Nullav)
52 #  define CopFILE(c)		(CopFILESV(c) ? SvPVX(CopFILESV(c)) : Nullch)
53 #  define CopSTASH(c)		((c)->cop_stash)
54 #  define CopSTASH_set(c,hv)	((c)->cop_stash = (hv))
55 #  define CopSTASHPV(c)		(CopSTASH(c) ? HvNAME(CopSTASH(c)) : Nullch)
56    /* cop_stash is not refcounted */
57 #  define CopSTASHPV_set(c,pv)	CopSTASH_set((c), gv_stashpv(pv,GV_ADD))
58 #  define CopSTASH_eq(c,hv)	(CopSTASH(c) == (hv))
59 #endif /* USE_ITHREADS */
60 
61 #define CopSTASH_ne(c,hv)	(!CopSTASH_eq(c,hv))
62 #define CopLINE(c)		((c)->cop_line)
63 #define CopLINE_inc(c)		(++CopLINE(c))
64 #define CopLINE_dec(c)		(--CopLINE(c))
65 #define CopLINE_set(c,l)	(CopLINE(c) = (l))
66 
67 /*
68  * Here we have some enormously heavy (or at least ponderous) wizardry.
69  */
70 
71 /* subroutine context */
72 struct block_sub {
73     CV *	cv;
74     GV *	gv;
75     GV *	dfoutgv;
76 #ifndef USE_THREADS
77     AV *	savearray;
78 #endif /* USE_THREADS */
79     AV *	argarray;
80     U16		olddepth;
81     U8		hasargs;
82     U8		lval;		/* XXX merge lval and hasargs? */
83     SV **	oldcurpad;
84 };
85 
86 #define PUSHSUB(cx)							\
87 	cx->blk_sub.cv = cv;						\
88 	cx->blk_sub.olddepth = CvDEPTH(cv);				\
89 	cx->blk_sub.hasargs = hasargs;					\
90 	cx->blk_sub.lval = PL_op->op_private &                          \
91 	                      (OPpLVAL_INTRO|OPpENTERSUB_INARGS);
92 
93 #define PUSHFORMAT(cx)							\
94 	cx->blk_sub.cv = cv;						\
95 	cx->blk_sub.gv = gv;						\
96 	cx->blk_sub.hasargs = 0;					\
97 	cx->blk_sub.dfoutgv = PL_defoutgv;				\
98 	(void)SvREFCNT_inc(cx->blk_sub.dfoutgv)
99 
100 #ifdef USE_THREADS
101 #  define POP_SAVEARRAY() NOOP
102 #else
103 #  define POP_SAVEARRAY()						\
104     STMT_START {							\
105 	SvREFCNT_dec(GvAV(PL_defgv));					\
106 	GvAV(PL_defgv) = cx->blk_sub.savearray;				\
107     } STMT_END
108 #endif /* USE_THREADS */
109 
110 /* junk in @_ spells trouble when cloning CVs and in pp_caller(), so don't
111  * leave any (a fast av_clear(ary), basically) */
112 #define CLEAR_ARGARRAY(ary) \
113     STMT_START {							\
114 	AvMAX(ary) += AvARRAY(ary) - AvALLOC(ary);			\
115 	SvPVX(ary) = (char*)AvALLOC(ary);				\
116 	AvFILLp(ary) = -1;						\
117     } STMT_END
118 
119 #define POPSUB(cx,sv)							\
120     STMT_START {							\
121 	if (cx->blk_sub.hasargs) {					\
122 	    POP_SAVEARRAY();						\
123 	    /* abandon @_ if it got reified */				\
124 	    if (AvREAL(cx->blk_sub.argarray)) {				\
125 		SSize_t fill = AvFILLp(cx->blk_sub.argarray);		\
126 		SvREFCNT_dec(cx->blk_sub.argarray);			\
127 		cx->blk_sub.argarray = newAV();				\
128 		av_extend(cx->blk_sub.argarray, fill);			\
129 		AvFLAGS(cx->blk_sub.argarray) = AVf_REIFY;		\
130 		cx->blk_sub.oldcurpad[0] = (SV*)cx->blk_sub.argarray;	\
131 	    }								\
132 	    else {							\
133 		CLEAR_ARGARRAY(cx->blk_sub.argarray);			\
134 	    }								\
135 	}								\
136 	sv = (SV*)cx->blk_sub.cv;					\
137 	if (sv && (CvDEPTH((CV*)sv) = cx->blk_sub.olddepth))		\
138 	    sv = Nullsv;						\
139     } STMT_END
140 
141 #define LEAVESUB(sv)							\
142     STMT_START {							\
143 	if (sv)								\
144 	    SvREFCNT_dec(sv);						\
145     } STMT_END
146 
147 #define POPFORMAT(cx)							\
148 	setdefout(cx->blk_sub.dfoutgv);					\
149 	SvREFCNT_dec(cx->blk_sub.dfoutgv);
150 
151 /* eval context */
152 struct block_eval {
153     I32		old_in_eval;
154     I32		old_op_type;
155     SV *	old_namesv;
156     OP *	old_eval_root;
157     SV *	cur_text;
158 };
159 
160 #define PUSHEVAL(cx,n,fgv)						\
161     STMT_START {							\
162 	cx->blk_eval.old_in_eval = PL_in_eval;				\
163 	cx->blk_eval.old_op_type = PL_op->op_type;			\
164 	cx->blk_eval.old_namesv = (n ? newSVpv(n,0) : Nullsv);		\
165 	cx->blk_eval.old_eval_root = PL_eval_root;			\
166 	cx->blk_eval.cur_text = PL_linestr;				\
167     } STMT_END
168 
169 #define POPEVAL(cx)							\
170     STMT_START {							\
171 	PL_in_eval = cx->blk_eval.old_in_eval;				\
172 	optype = cx->blk_eval.old_op_type;				\
173 	PL_eval_root = cx->blk_eval.old_eval_root;			\
174 	if (cx->blk_eval.old_namesv)					\
175 	    sv_2mortal(cx->blk_eval.old_namesv);			\
176     } STMT_END
177 
178 /* loop context */
179 struct block_loop {
180     char *	label;
181     I32		resetsp;
182     OP *	redo_op;
183     OP *	next_op;
184     OP *	last_op;
185 #ifdef USE_ITHREADS
186     void *	iterdata;
187     SV **	oldcurpad;
188 #else
189     SV **	itervar;
190 #endif
191     SV *	itersave;
192     SV *	iterlval;
193     AV *	iterary;
194     IV		iterix;
195     IV		itermax;
196 };
197 
198 #ifdef USE_ITHREADS
199 #  define CxITERVAR(c)							\
200 	((c)->blk_loop.iterdata						\
201 	 ? (CxPADLOOP(cx) 						\
202 	    ? &((c)->blk_loop.oldcurpad)[(PADOFFSET)(c)->blk_loop.iterdata]	\
203 	    : &GvSV((GV*)(c)->blk_loop.iterdata))			\
204 	 : (SV**)NULL)
205 #  define CX_ITERDATA_SET(cx,idata)					\
206 	cx->blk_loop.oldcurpad = PL_curpad;				\
207 	if ((cx->blk_loop.iterdata = (idata)))				\
208 	    cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));
209 #else
210 #  define CxITERVAR(c)		((c)->blk_loop.itervar)
211 #  define CX_ITERDATA_SET(cx,ivar)					\
212 	if ((cx->blk_loop.itervar = (SV**)(ivar)))			\
213 	    cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));
214 #endif
215 
216 #define PUSHLOOP(cx, dat, s)						\
217 	cx->blk_loop.label = PL_curcop->cop_label;			\
218 	cx->blk_loop.resetsp = s - PL_stack_base;			\
219 	cx->blk_loop.redo_op = cLOOP->op_redoop;			\
220 	cx->blk_loop.next_op = cLOOP->op_nextop;			\
221 	cx->blk_loop.last_op = cLOOP->op_lastop;			\
222 	cx->blk_loop.iterlval = Nullsv;					\
223 	cx->blk_loop.iterary = Nullav;					\
224 	cx->blk_loop.iterix = -1;					\
225 	CX_ITERDATA_SET(cx,dat);
226 
227 #define POPLOOP(cx)							\
228 	SvREFCNT_dec(cx->blk_loop.iterlval);				\
229 	if (CxITERVAR(cx)) {						\
230 	    SV **s_v_p = CxITERVAR(cx);					\
231 	    sv_2mortal(*s_v_p);						\
232 	    *s_v_p = cx->blk_loop.itersave;				\
233 	}								\
234 	if (cx->blk_loop.iterary && cx->blk_loop.iterary != PL_curstack)\
235 	    SvREFCNT_dec(cx->blk_loop.iterary);
236 
237 /* context common to subroutines, evals and loops */
238 struct block {
239     I32		blku_oldsp;	/* stack pointer to copy stuff down to */
240     COP *	blku_oldcop;	/* old curcop pointer */
241     I32		blku_oldretsp;	/* return stack index */
242     I32		blku_oldmarksp;	/* mark stack index */
243     I32		blku_oldscopesp;	/* scope stack index */
244     PMOP *	blku_oldpm;	/* values of pattern match vars */
245     U8		blku_gimme;	/* is this block running in list context? */
246 
247     union {
248 	struct block_sub	blku_sub;
249 	struct block_eval	blku_eval;
250 	struct block_loop	blku_loop;
251     } blk_u;
252 };
253 #define blk_oldsp	cx_u.cx_blk.blku_oldsp
254 #define blk_oldcop	cx_u.cx_blk.blku_oldcop
255 #define blk_oldretsp	cx_u.cx_blk.blku_oldretsp
256 #define blk_oldmarksp	cx_u.cx_blk.blku_oldmarksp
257 #define blk_oldscopesp	cx_u.cx_blk.blku_oldscopesp
258 #define blk_oldpm	cx_u.cx_blk.blku_oldpm
259 #define blk_gimme	cx_u.cx_blk.blku_gimme
260 #define blk_sub		cx_u.cx_blk.blk_u.blku_sub
261 #define blk_eval	cx_u.cx_blk.blk_u.blku_eval
262 #define blk_loop	cx_u.cx_blk.blk_u.blku_loop
263 
264 /* Enter a block. */
265 #define PUSHBLOCK(cx,t,sp) CXINC, cx = &cxstack[cxstack_ix],		\
266 	cx->cx_type		= t,					\
267 	cx->blk_oldsp		= sp - PL_stack_base,			\
268 	cx->blk_oldcop		= PL_curcop,				\
269 	cx->blk_oldmarksp	= PL_markstack_ptr - PL_markstack,	\
270 	cx->blk_oldscopesp	= PL_scopestack_ix,			\
271 	cx->blk_oldretsp	= PL_retstack_ix,			\
272 	cx->blk_oldpm		= PL_curpm,				\
273 	cx->blk_gimme		= gimme;				\
274 	DEBUG_l( PerlIO_printf(Perl_debug_log, "Entering block %ld, type %s\n",	\
275 		    (long)cxstack_ix, PL_block_type[CxTYPE(cx)]); )
276 
277 /* Exit a block (RETURN and LAST). */
278 #define POPBLOCK(cx,pm) cx = &cxstack[cxstack_ix--],			\
279 	newsp		 = PL_stack_base + cx->blk_oldsp,		\
280 	PL_curcop	 = cx->blk_oldcop,				\
281 	PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,		\
282 	PL_scopestack_ix = cx->blk_oldscopesp,				\
283 	PL_retstack_ix	 = cx->blk_oldretsp,				\
284 	pm		 = cx->blk_oldpm,				\
285 	gimme		 = cx->blk_gimme;				\
286 	DEBUG_l( PerlIO_printf(Perl_debug_log, "Leaving block %ld, type %s\n",		\
287 		    (long)cxstack_ix+1,PL_block_type[CxTYPE(cx)]); )
288 
289 /* Continue a block elsewhere (NEXT and REDO). */
290 #define TOPBLOCK(cx) cx  = &cxstack[cxstack_ix],			\
291 	PL_stack_sp	 = PL_stack_base + cx->blk_oldsp,		\
292 	PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,		\
293 	PL_scopestack_ix = cx->blk_oldscopesp,				\
294 	PL_retstack_ix	 = cx->blk_oldretsp,				\
295 	PL_curpm         = cx->blk_oldpm
296 
297 /* substitution context */
298 struct subst {
299     I32		sbu_iters;
300     I32		sbu_maxiters;
301     I32		sbu_rflags;
302     I32		sbu_oldsave;
303     bool	sbu_once;
304     bool	sbu_rxtainted;
305     char *	sbu_orig;
306     SV *	sbu_dstr;
307     SV *	sbu_targ;
308     char *	sbu_s;
309     char *	sbu_m;
310     char *	sbu_strend;
311     void *	sbu_rxres;
312     REGEXP *	sbu_rx;
313 };
314 #define sb_iters	cx_u.cx_subst.sbu_iters
315 #define sb_maxiters	cx_u.cx_subst.sbu_maxiters
316 #define sb_rflags	cx_u.cx_subst.sbu_rflags
317 #define sb_oldsave	cx_u.cx_subst.sbu_oldsave
318 #define sb_once		cx_u.cx_subst.sbu_once
319 #define sb_rxtainted	cx_u.cx_subst.sbu_rxtainted
320 #define sb_orig		cx_u.cx_subst.sbu_orig
321 #define sb_dstr		cx_u.cx_subst.sbu_dstr
322 #define sb_targ		cx_u.cx_subst.sbu_targ
323 #define sb_s		cx_u.cx_subst.sbu_s
324 #define sb_m		cx_u.cx_subst.sbu_m
325 #define sb_strend	cx_u.cx_subst.sbu_strend
326 #define sb_rxres	cx_u.cx_subst.sbu_rxres
327 #define sb_rx		cx_u.cx_subst.sbu_rx
328 
329 #define PUSHSUBST(cx) CXINC, cx = &cxstack[cxstack_ix],			\
330 	cx->sb_iters		= iters,				\
331 	cx->sb_maxiters		= maxiters,				\
332 	cx->sb_rflags		= r_flags,				\
333 	cx->sb_oldsave		= oldsave,				\
334 	cx->sb_once		= once,					\
335 	cx->sb_rxtainted	= rxtainted,				\
336 	cx->sb_orig		= orig,					\
337 	cx->sb_dstr		= dstr,					\
338 	cx->sb_targ		= targ,					\
339 	cx->sb_s		= s,					\
340 	cx->sb_m		= m,					\
341 	cx->sb_strend		= strend,				\
342 	cx->sb_rxres		= Null(void*),				\
343 	cx->sb_rx		= rx,					\
344 	cx->cx_type		= CXt_SUBST;				\
345 	rxres_save(&cx->sb_rxres, rx)
346 
347 #define POPSUBST(cx) cx = &cxstack[cxstack_ix--];			\
348 	rxres_free(&cx->sb_rxres)
349 
350 struct context {
351     U32		cx_type;	/* what kind of context this is */
352     union {
353 	struct block	cx_blk;
354 	struct subst	cx_subst;
355     } cx_u;
356 };
357 
358 #define CXTYPEMASK	0xff
359 #define CXt_NULL	0
360 #define CXt_SUB		1
361 #define CXt_EVAL	2
362 #define CXt_LOOP	3
363 #define CXt_SUBST	4
364 #define CXt_BLOCK	5
365 #define CXt_FORMAT	6
366 
367 /* private flags for CXt_EVAL */
368 #define CXp_REAL	0x00000100	/* truly eval'', not a lookalike */
369 #define CXp_TRYBLOCK	0x00000200	/* eval{}, not eval'' or similar */
370 
371 #ifdef USE_ITHREADS
372 /* private flags for CXt_LOOP */
373 #  define CXp_PADVAR	0x00000100	/* itervar lives on pad, iterdata
374 					   has pad offset; if not set,
375 					   iterdata holds GV* */
376 #  define CxPADLOOP(c)	(((c)->cx_type & (CXt_LOOP|CXp_PADVAR))		\
377 			 == (CXt_LOOP|CXp_PADVAR))
378 #endif
379 
380 #define CxTYPE(c)	((c)->cx_type & CXTYPEMASK)
381 #define CxREALEVAL(c)	(((c)->cx_type & (CXt_EVAL|CXp_REAL))		\
382 			 == (CXt_EVAL|CXp_REAL))
383 #define CxTRYBLOCK(c)	(((c)->cx_type & (CXt_EVAL|CXp_TRYBLOCK))	\
384 			 == (CXt_EVAL|CXp_TRYBLOCK))
385 
386 #define CXINC (cxstack_ix < cxstack_max ? ++cxstack_ix : (cxstack_ix = cxinc()))
387 
388 /* "gimme" values */
389 
390 /*
391 =for apidoc AmU||G_SCALAR
392 Used to indicate scalar context.  See C<GIMME_V>, C<GIMME>, and
393 L<perlcall>.
394 
395 =for apidoc AmU||G_ARRAY
396 Used to indicate list context.  See C<GIMME_V>, C<GIMME> and
397 L<perlcall>.
398 
399 =for apidoc AmU||G_VOID
400 Used to indicate void context.  See C<GIMME_V> and L<perlcall>.
401 
402 =for apidoc AmU||G_DISCARD
403 Indicates that arguments returned from a callback should be discarded.  See
404 L<perlcall>.
405 
406 =for apidoc AmU||G_EVAL
407 
408 Used to force a Perl C<eval> wrapper around a callback.  See
409 L<perlcall>.
410 
411 =for apidoc AmU||G_NOARGS
412 
413 Indicates that no arguments are being sent to a callback.  See
414 L<perlcall>.
415 
416 =cut
417 */
418 
419 #define G_SCALAR	0
420 #define G_ARRAY		1
421 #define G_VOID		128	/* skip this bit when adding flags below */
422 
423 /* extra flags for Perl_call_* routines */
424 #define G_DISCARD	2	/* Call FREETMPS. */
425 #define G_EVAL		4	/* Assume eval {} around subroutine call. */
426 #define G_NOARGS	8	/* Don't construct a @_ array. */
427 #define G_KEEPERR      16	/* Append errors to $@, don't overwrite it */
428 #define G_NODEBUG      32	/* Disable debugging at toplevel.  */
429 #define G_METHOD       64       /* Calling method. */
430 
431 /* flag bits for PL_in_eval */
432 #define EVAL_NULL	0	/* not in an eval */
433 #define EVAL_INEVAL	1	/* some enclosing scope is an eval */
434 #define EVAL_WARNONLY	2	/* used by yywarn() when calling yyerror() */
435 #define EVAL_KEEPERR	4	/* set by Perl_call_sv if G_KEEPERR */
436 #define EVAL_INREQUIRE	8	/* The code is being required. */
437 
438 /* Support for switching (stack and block) contexts.
439  * This ensures magic doesn't invalidate local stack and cx pointers.
440  */
441 
442 #define PERLSI_UNKNOWN		-1
443 #define PERLSI_UNDEF		0
444 #define PERLSI_MAIN		1
445 #define PERLSI_MAGIC		2
446 #define PERLSI_SORT		3
447 #define PERLSI_SIGNAL		4
448 #define PERLSI_OVERLOAD		5
449 #define PERLSI_DESTROY		6
450 #define PERLSI_WARNHOOK		7
451 #define PERLSI_DIEHOOK		8
452 #define PERLSI_REQUIRE		9
453 
454 struct stackinfo {
455     AV *		si_stack;	/* stack for current runlevel */
456     PERL_CONTEXT *	si_cxstack;	/* context stack for runlevel */
457     I32			si_cxix;	/* current context index */
458     I32			si_cxmax;	/* maximum allocated index */
459     I32			si_type;	/* type of runlevel */
460     struct stackinfo *	si_prev;
461     struct stackinfo *	si_next;
462     I32			si_markoff;	/* offset where markstack begins for us.
463 					 * currently used only with DEBUGGING,
464 					 * but not #ifdef-ed for bincompat */
465 };
466 
467 typedef struct stackinfo PERL_SI;
468 
469 #define cxstack		(PL_curstackinfo->si_cxstack)
470 #define cxstack_ix	(PL_curstackinfo->si_cxix)
471 #define cxstack_max	(PL_curstackinfo->si_cxmax)
472 
473 #ifdef DEBUGGING
474 #  define	SET_MARK_OFFSET \
475     PL_curstackinfo->si_markoff = PL_markstack_ptr - PL_markstack
476 #else
477 #  define	SET_MARK_OFFSET NOOP
478 #endif
479 
480 #define PUSHSTACKi(type) \
481     STMT_START {							\
482 	PERL_SI *next = PL_curstackinfo->si_next;			\
483 	if (!next) {							\
484 	    next = new_stackinfo(32, 2048/sizeof(PERL_CONTEXT) - 1);	\
485 	    next->si_prev = PL_curstackinfo;				\
486 	    PL_curstackinfo->si_next = next;				\
487 	}								\
488 	next->si_type = type;						\
489 	next->si_cxix = -1;						\
490 	AvFILLp(next->si_stack) = 0;					\
491 	SWITCHSTACK(PL_curstack,next->si_stack);			\
492 	PL_curstackinfo = next;						\
493 	SET_MARK_OFFSET;						\
494     } STMT_END
495 
496 #define PUSHSTACK PUSHSTACKi(PERLSI_UNKNOWN)
497 
498 /* POPSTACK works with PL_stack_sp, so it may need to be bracketed by
499  * PUTBACK/SPAGAIN to flush/refresh any local SP that may be active */
500 #define POPSTACK \
501     STMT_START {							\
502 	dSP;								\
503 	PERL_SI *prev = PL_curstackinfo->si_prev;			\
504 	if (!prev) {							\
505 	    PerlIO_printf(Perl_error_log, "panic: POPSTACK\n");		\
506 	    my_exit(1);							\
507 	}								\
508 	SWITCHSTACK(PL_curstack,prev->si_stack);			\
509 	/* don't free prev here, free them all at the END{} */		\
510 	PL_curstackinfo = prev;						\
511     } STMT_END
512 
513 #define POPSTACK_TO(s) \
514     STMT_START {							\
515 	while (PL_curstack != s) {					\
516 	    dounwind(-1);						\
517 	    POPSTACK;							\
518 	}								\
519     } STMT_END
520