xref: /onnv-gate/usr/src/cmd/perl/5.8.4/distrib/cop.h (revision 0:68f95e015346)
1 /*    cop.h
2  *
3  *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
4  *    2000, 2001, 2002, 2003, 2004, 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  * Control ops (cops) are one of the three ops OP_NEXTSTATE, OP_DBSTATE,
10  * and OP_SETSTATE that (loosely speaking) are separate statements.
11  * They hold information important for lexical state and error reporting.
12  * At run time, PL_curcop is set to point to the most recently executed cop,
13  * and thus can be used to determine our current state.
14  */
15 
16 struct cop {
17     BASEOP
18     char *	cop_label;	/* label for this construct */
19 #ifdef USE_ITHREADS
20     char *	cop_stashpv;	/* package line was compiled in */
21     char *	cop_file;	/* file name the following line # is from */
22 #else
23     HV *	cop_stash;	/* package line was compiled in */
24     GV *	cop_filegv;	/* file the following line # is from */
25 #endif
26     U32		cop_seq;	/* parse sequence number */
27     I32		cop_arybase;	/* array base this line was compiled with */
28     line_t      cop_line;       /* line # of this command */
29     SV *	cop_warnings;	/* lexical warnings bitmask */
30     SV *	cop_io;		/* lexical IO defaults */
31 };
32 
33 #define Nullcop Null(COP*)
34 
35 #ifdef USE_ITHREADS
36 #  define CopFILE(c)		((c)->cop_file)
37 #  define CopFILEGV(c)		(CopFILE(c) \
38 				 ? gv_fetchfile(CopFILE(c)) : Nullgv)
39 
40 #  ifdef NETWARE
41 #    define CopFILE_set(c,pv)	((c)->cop_file = savepv(pv))
42 #  else
43 #    define CopFILE_set(c,pv)	((c)->cop_file = savesharedpv(pv))
44 #  endif
45 
46 #  define CopFILESV(c)		(CopFILE(c) \
47 				 ? GvSV(gv_fetchfile(CopFILE(c))) : Nullsv)
48 #  define CopFILEAV(c)		(CopFILE(c) \
49 				 ? GvAV(gv_fetchfile(CopFILE(c))) : Nullav)
50 #  define CopSTASHPV(c)		((c)->cop_stashpv)
51 
52 #  ifdef NETWARE
53 #    define CopSTASHPV_set(c,pv)	((c)->cop_stashpv = ((pv) ? savepv(pv) : Nullch))
54 #  else
55 #    define CopSTASHPV_set(c,pv)	((c)->cop_stashpv = savesharedpv(pv))
56 #  endif
57 
58 #  define CopSTASH(c)		(CopSTASHPV(c) \
59 				 ? gv_stashpv(CopSTASHPV(c),GV_ADD) : Nullhv)
60 #  define CopSTASH_set(c,hv)	CopSTASHPV_set(c, (hv) ? HvNAME(hv) : Nullch)
61 #  define CopSTASH_eq(c,hv)	((hv) 					\
62 				 && (CopSTASHPV(c) == HvNAME(hv)	\
63 				     || (CopSTASHPV(c) && HvNAME(hv)	\
64 					 && strEQ(CopSTASHPV(c), HvNAME(hv)))))
65 #  ifdef NETWARE
66 #    define CopSTASH_free(c) SAVECOPSTASH_FREE(c)
67 #  else
68 #    define CopSTASH_free(c)	PerlMemShared_free(CopSTASHPV(c))
69 #  endif
70 
71 #  ifdef NETWARE
72 #    define CopFILE_free(c) SAVECOPFILE_FREE(c)
73 #  else
74 #    define CopFILE_free(c)	(PerlMemShared_free(CopFILE(c)),(CopFILE(c) = Nullch))
75 #  endif
76 #else
77 #  define CopFILEGV(c)		((c)->cop_filegv)
78 #  define CopFILEGV_set(c,gv)	((c)->cop_filegv = (GV*)SvREFCNT_inc(gv))
79 #  define CopFILE_set(c,pv)	CopFILEGV_set((c), gv_fetchfile(pv))
80 #  define CopFILESV(c)		(CopFILEGV(c) ? GvSV(CopFILEGV(c)) : Nullsv)
81 #  define CopFILEAV(c)		(CopFILEGV(c) ? GvAV(CopFILEGV(c)) : Nullav)
82 #  define CopFILE(c)		(CopFILESV(c) ? SvPVX(CopFILESV(c)) : Nullch)
83 #  define CopSTASH(c)		((c)->cop_stash)
84 #  define CopSTASH_set(c,hv)	((c)->cop_stash = (hv))
85 #  define CopSTASHPV(c)		(CopSTASH(c) ? HvNAME(CopSTASH(c)) : Nullch)
86    /* cop_stash is not refcounted */
87 #  define CopSTASHPV_set(c,pv)	CopSTASH_set((c), gv_stashpv(pv,GV_ADD))
88 #  define CopSTASH_eq(c,hv)	(CopSTASH(c) == (hv))
89 #  define CopSTASH_free(c)
90 #  define CopFILE_free(c)	(SvREFCNT_dec(CopFILEGV(c)),(CopFILEGV(c) = Nullgv))
91 
92 #endif /* USE_ITHREADS */
93 
94 #define CopSTASH_ne(c,hv)	(!CopSTASH_eq(c,hv))
95 #define CopLINE(c)		((c)->cop_line)
96 #define CopLINE_inc(c)		(++CopLINE(c))
97 #define CopLINE_dec(c)		(--CopLINE(c))
98 #define CopLINE_set(c,l)	(CopLINE(c) = (l))
99 
100 /* OutCopFILE() is CopFILE for output (caller, die, warn, etc.) */
101 #ifdef MACOS_TRADITIONAL
102 #  define OutCopFILE(c) MacPerl_MPWFileName(CopFILE(c))
103 #else
104 #  define OutCopFILE(c) CopFILE(c)
105 #endif
106 
107 /*
108  * Here we have some enormously heavy (or at least ponderous) wizardry.
109  */
110 
111 /* subroutine context */
112 struct block_sub {
113     CV *	cv;
114     GV *	gv;
115     GV *	dfoutgv;
116 #ifndef USE_5005THREADS
117     AV *	savearray;
118 #endif /* USE_5005THREADS */
119     AV *	argarray;
120     long	olddepth;
121     U8		hasargs;
122     U8		lval;		/* XXX merge lval and hasargs? */
123     PAD		*oldcomppad;
124 };
125 
126 /* base for the next two macros. Don't use directly.
127  * Note that the refcnt of the cv is incremented twice;  The CX one is
128  * decremented by LEAVESUB, the other by LEAVE. */
129 
130 #define PUSHSUB_BASE(cx)						\
131 	cx->blk_sub.cv = cv;						\
132 	cx->blk_sub.olddepth = CvDEPTH(cv);				\
133 	cx->blk_sub.hasargs = hasargs;					\
134 	if (!CvDEPTH(cv)) {						\
135 	    (void)SvREFCNT_inc(cv);					\
136 	    (void)SvREFCNT_inc(cv);					\
137 	    SAVEFREESV(cv);						\
138 	}
139 
140 
141 #define PUSHSUB(cx)							\
142 	PUSHSUB_BASE(cx)						\
143 	cx->blk_sub.lval = PL_op->op_private &                          \
144 	                      (OPpLVAL_INTRO|OPpENTERSUB_INARGS);
145 
146 /* variant for use by OP_DBSTATE, where op_private holds hint bits */
147 #define PUSHSUB_DB(cx)							\
148 	PUSHSUB_BASE(cx)						\
149 	cx->blk_sub.lval = 0;
150 
151 
152 #define PUSHFORMAT(cx)							\
153 	cx->blk_sub.cv = cv;						\
154 	cx->blk_sub.gv = gv;						\
155 	cx->blk_sub.hasargs = 0;					\
156 	cx->blk_sub.dfoutgv = PL_defoutgv;				\
157 	(void)SvREFCNT_inc(cx->blk_sub.dfoutgv)
158 
159 #ifdef USE_5005THREADS
160 #  define POP_SAVEARRAY() NOOP
161 #else
162 #  define POP_SAVEARRAY()						\
163     STMT_START {							\
164 	SvREFCNT_dec(GvAV(PL_defgv));					\
165 	GvAV(PL_defgv) = cx->blk_sub.savearray;				\
166     } STMT_END
167 #endif /* USE_5005THREADS */
168 
169 /* junk in @_ spells trouble when cloning CVs and in pp_caller(), so don't
170  * leave any (a fast av_clear(ary), basically) */
171 #define CLEAR_ARGARRAY(ary) \
172     STMT_START {							\
173 	AvMAX(ary) += AvARRAY(ary) - AvALLOC(ary);			\
174 	SvPVX(ary) = (char*)AvALLOC(ary);				\
175 	AvFILLp(ary) = -1;						\
176     } STMT_END
177 
178 #define POPSUB(cx,sv)							\
179     STMT_START {							\
180 	if (cx->blk_sub.hasargs) {					\
181 	    POP_SAVEARRAY();						\
182 	    /* abandon @_ if it got reified */				\
183 	    if (AvREAL(cx->blk_sub.argarray)) {				\
184 		SSize_t fill = AvFILLp(cx->blk_sub.argarray);		\
185 		SvREFCNT_dec(cx->blk_sub.argarray);			\
186 		cx->blk_sub.argarray = newAV();				\
187 		av_extend(cx->blk_sub.argarray, fill);			\
188 		AvFLAGS(cx->blk_sub.argarray) = AVf_REIFY;		\
189 		CX_CURPAD_SV(cx->blk_sub, 0) = (SV*)cx->blk_sub.argarray;	\
190 	    }								\
191 	    else {							\
192 		CLEAR_ARGARRAY(cx->blk_sub.argarray);			\
193 	    }								\
194 	}								\
195 	sv = (SV*)cx->blk_sub.cv;					\
196 	if (sv && (CvDEPTH((CV*)sv) = cx->blk_sub.olddepth))		\
197 	    sv = Nullsv;						\
198     } STMT_END
199 
200 #define LEAVESUB(sv)							\
201     STMT_START {							\
202 	if (sv)								\
203 	    SvREFCNT_dec(sv);						\
204     } STMT_END
205 
206 #define POPFORMAT(cx)							\
207 	setdefout(cx->blk_sub.dfoutgv);					\
208 	SvREFCNT_dec(cx->blk_sub.dfoutgv);
209 
210 /* eval context */
211 struct block_eval {
212     I32		old_in_eval;
213     I32		old_op_type;
214     SV *	old_namesv;
215     OP *	old_eval_root;
216     SV *	cur_text;
217     CV *	cv;
218 };
219 
220 #define PUSHEVAL(cx,n,fgv)						\
221     STMT_START {							\
222 	cx->blk_eval.old_in_eval = PL_in_eval;				\
223 	cx->blk_eval.old_op_type = PL_op->op_type;			\
224 	cx->blk_eval.old_namesv = (n ? newSVpv(n,0) : Nullsv);		\
225 	cx->blk_eval.old_eval_root = PL_eval_root;			\
226 	cx->blk_eval.cur_text = PL_linestr;				\
227 	cx->blk_eval.cv = Nullcv; /* set by doeval(), as applicable */	\
228     } STMT_END
229 
230 #define POPEVAL(cx)							\
231     STMT_START {							\
232 	PL_in_eval = cx->blk_eval.old_in_eval;				\
233 	optype = cx->blk_eval.old_op_type;				\
234 	PL_eval_root = cx->blk_eval.old_eval_root;			\
235 	if (cx->blk_eval.old_namesv)					\
236 	    sv_2mortal(cx->blk_eval.old_namesv);			\
237     } STMT_END
238 
239 /* loop context */
240 struct block_loop {
241     char *	label;
242     I32		resetsp;
243     OP *	redo_op;
244     OP *	next_op;
245     OP *	last_op;
246 #ifdef USE_ITHREADS
247     void *	iterdata;
248     PAD		*oldcomppad;
249 #else
250     SV **	itervar;
251 #endif
252     SV *	itersave;
253     SV *	iterlval;
254     AV *	iterary;
255     IV		iterix;
256     IV		itermax;
257 };
258 
259 #ifdef USE_ITHREADS
260 #  define CxITERVAR(c)							\
261 	((c)->blk_loop.iterdata						\
262 	 ? (CxPADLOOP(cx) 						\
263 	    ? &CX_CURPAD_SV( (c)->blk_loop, 				\
264 		    INT2PTR(PADOFFSET, (c)->blk_loop.iterdata))		\
265 	    : &GvSV((GV*)(c)->blk_loop.iterdata))			\
266 	 : (SV**)NULL)
267 #  define CX_ITERDATA_SET(cx,idata)					\
268 	CX_CURPAD_SAVE(cx->blk_loop);					\
269 	if ((cx->blk_loop.iterdata = (idata)))				\
270 	    cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));	\
271 	else								\
272 	    cx->blk_loop.itersave = Nullsv;
273 #else
274 #  define CxITERVAR(c)		((c)->blk_loop.itervar)
275 #  define CX_ITERDATA_SET(cx,ivar)					\
276 	if ((cx->blk_loop.itervar = (SV**)(ivar)))			\
277 	    cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));	\
278 	else								\
279 	    cx->blk_loop.itersave = Nullsv;
280 #endif
281 
282 #define PUSHLOOP(cx, dat, s)						\
283 	cx->blk_loop.label = PL_curcop->cop_label;			\
284 	cx->blk_loop.resetsp = s - PL_stack_base;			\
285 	cx->blk_loop.redo_op = cLOOP->op_redoop;			\
286 	cx->blk_loop.next_op = cLOOP->op_nextop;			\
287 	cx->blk_loop.last_op = cLOOP->op_lastop;			\
288 	cx->blk_loop.iterlval = Nullsv;					\
289 	cx->blk_loop.iterary = Nullav;					\
290 	cx->blk_loop.iterix = -1;					\
291 	CX_ITERDATA_SET(cx,dat);
292 
293 #define POPLOOP(cx)							\
294 	SvREFCNT_dec(cx->blk_loop.iterlval);				\
295 	if (CxITERVAR(cx)) {						\
296 	    SV **s_v_p = CxITERVAR(cx);					\
297 	    sv_2mortal(*s_v_p);						\
298 	    *s_v_p = cx->blk_loop.itersave;				\
299 	}								\
300 	if (cx->blk_loop.iterary && cx->blk_loop.iterary != PL_curstack)\
301 	    SvREFCNT_dec(cx->blk_loop.iterary);
302 
303 /* context common to subroutines, evals and loops */
304 struct block {
305     I32		blku_oldsp;	/* stack pointer to copy stuff down to */
306     COP *	blku_oldcop;	/* old curcop pointer */
307     I32		blku_oldretsp;	/* return stack index */
308     I32		blku_oldmarksp;	/* mark stack index */
309     I32		blku_oldscopesp;	/* scope stack index */
310     PMOP *	blku_oldpm;	/* values of pattern match vars */
311     U8		blku_gimme;	/* is this block running in list context? */
312 
313     union {
314 	struct block_sub	blku_sub;
315 	struct block_eval	blku_eval;
316 	struct block_loop	blku_loop;
317     } blk_u;
318 };
319 #define blk_oldsp	cx_u.cx_blk.blku_oldsp
320 #define blk_oldcop	cx_u.cx_blk.blku_oldcop
321 #define blk_oldretsp	cx_u.cx_blk.blku_oldretsp
322 #define blk_oldmarksp	cx_u.cx_blk.blku_oldmarksp
323 #define blk_oldscopesp	cx_u.cx_blk.blku_oldscopesp
324 #define blk_oldpm	cx_u.cx_blk.blku_oldpm
325 #define blk_gimme	cx_u.cx_blk.blku_gimme
326 #define blk_sub		cx_u.cx_blk.blk_u.blku_sub
327 #define blk_eval	cx_u.cx_blk.blk_u.blku_eval
328 #define blk_loop	cx_u.cx_blk.blk_u.blku_loop
329 
330 /* Enter a block. */
331 #define PUSHBLOCK(cx,t,sp) CXINC, cx = &cxstack[cxstack_ix],		\
332 	cx->cx_type		= t,					\
333 	cx->blk_oldsp		= sp - PL_stack_base,			\
334 	cx->blk_oldcop		= PL_curcop,				\
335 	cx->blk_oldmarksp	= PL_markstack_ptr - PL_markstack,	\
336 	cx->blk_oldscopesp	= PL_scopestack_ix,			\
337 	cx->blk_oldretsp	= PL_retstack_ix,			\
338 	cx->blk_oldpm		= PL_curpm,				\
339 	cx->blk_gimme		= (U8)gimme;				\
340 	DEBUG_l( PerlIO_printf(Perl_debug_log, "Entering block %ld, type %s\n",	\
341 		    (long)cxstack_ix, PL_block_type[CxTYPE(cx)]); )
342 
343 /* Exit a block (RETURN and LAST). */
344 #define POPBLOCK(cx,pm) cx = &cxstack[cxstack_ix--],			\
345 	newsp		 = PL_stack_base + cx->blk_oldsp,		\
346 	PL_curcop	 = cx->blk_oldcop,				\
347 	PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,		\
348 	PL_scopestack_ix = cx->blk_oldscopesp,				\
349 	PL_retstack_ix	 = cx->blk_oldretsp,				\
350 	pm		 = cx->blk_oldpm,				\
351 	gimme		 = cx->blk_gimme;				\
352 	DEBUG_SCOPE("POPBLOCK");					\
353 	DEBUG_l( PerlIO_printf(Perl_debug_log, "Leaving block %ld, type %s\n",		\
354 		    (long)cxstack_ix+1,PL_block_type[CxTYPE(cx)]); )
355 
356 /* Continue a block elsewhere (NEXT and REDO). */
357 #define TOPBLOCK(cx) cx  = &cxstack[cxstack_ix],			\
358 	PL_stack_sp	 = PL_stack_base + cx->blk_oldsp,		\
359 	PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,		\
360 	PL_scopestack_ix = cx->blk_oldscopesp,				\
361 	PL_retstack_ix	 = cx->blk_oldretsp,				\
362 	PL_curpm         = cx->blk_oldpm;				\
363 	DEBUG_SCOPE("TOPBLOCK");
364 
365 /* substitution context */
366 struct subst {
367     I32		sbu_iters;
368     I32		sbu_maxiters;
369     I32		sbu_rflags;
370     I32		sbu_oldsave;
371     bool	sbu_once;
372     bool	sbu_rxtainted;
373     char *	sbu_orig;
374     SV *	sbu_dstr;
375     SV *	sbu_targ;
376     char *	sbu_s;
377     char *	sbu_m;
378     char *	sbu_strend;
379     void *	sbu_rxres;
380     REGEXP *	sbu_rx;
381 };
382 #define sb_iters	cx_u.cx_subst.sbu_iters
383 #define sb_maxiters	cx_u.cx_subst.sbu_maxiters
384 #define sb_rflags	cx_u.cx_subst.sbu_rflags
385 #define sb_oldsave	cx_u.cx_subst.sbu_oldsave
386 #define sb_once		cx_u.cx_subst.sbu_once
387 #define sb_rxtainted	cx_u.cx_subst.sbu_rxtainted
388 #define sb_orig		cx_u.cx_subst.sbu_orig
389 #define sb_dstr		cx_u.cx_subst.sbu_dstr
390 #define sb_targ		cx_u.cx_subst.sbu_targ
391 #define sb_s		cx_u.cx_subst.sbu_s
392 #define sb_m		cx_u.cx_subst.sbu_m
393 #define sb_strend	cx_u.cx_subst.sbu_strend
394 #define sb_rxres	cx_u.cx_subst.sbu_rxres
395 #define sb_rx		cx_u.cx_subst.sbu_rx
396 
397 #define PUSHSUBST(cx) CXINC, cx = &cxstack[cxstack_ix],			\
398 	cx->sb_iters		= iters,				\
399 	cx->sb_maxiters		= maxiters,				\
400 	cx->sb_rflags		= r_flags,				\
401 	cx->sb_oldsave		= oldsave,				\
402 	cx->sb_once		= once,					\
403 	cx->sb_rxtainted	= rxtainted,				\
404 	cx->sb_orig		= orig,					\
405 	cx->sb_dstr		= dstr,					\
406 	cx->sb_targ		= targ,					\
407 	cx->sb_s		= s,					\
408 	cx->sb_m		= m,					\
409 	cx->sb_strend		= strend,				\
410 	cx->sb_rxres		= Null(void*),				\
411 	cx->sb_rx		= rx,					\
412 	cx->cx_type		= CXt_SUBST;				\
413 	rxres_save(&cx->sb_rxres, rx)
414 
415 #define POPSUBST(cx) cx = &cxstack[cxstack_ix--];			\
416 	rxres_free(&cx->sb_rxres)
417 
418 struct context {
419     U32		cx_type;	/* what kind of context this is */
420     union {
421 	struct block	cx_blk;
422 	struct subst	cx_subst;
423     } cx_u;
424 };
425 
426 #define CXTYPEMASK	0xff
427 #define CXt_NULL	0
428 #define CXt_SUB		1
429 #define CXt_EVAL	2
430 #define CXt_LOOP	3
431 #define CXt_SUBST	4
432 #define CXt_BLOCK	5
433 #define CXt_FORMAT	6
434 
435 /* private flags for CXt_EVAL */
436 #define CXp_REAL	0x00000100	/* truly eval'', not a lookalike */
437 #define CXp_TRYBLOCK	0x00000200	/* eval{}, not eval'' or similar */
438 
439 #ifdef USE_ITHREADS
440 /* private flags for CXt_LOOP */
441 #  define CXp_PADVAR	0x00000100	/* itervar lives on pad, iterdata
442 					   has pad offset; if not set,
443 					   iterdata holds GV* */
444 #  define CxPADLOOP(c)	(((c)->cx_type & (CXt_LOOP|CXp_PADVAR))		\
445 			 == (CXt_LOOP|CXp_PADVAR))
446 #endif
447 
448 #define CxTYPE(c)	((c)->cx_type & CXTYPEMASK)
449 #define CxREALEVAL(c)	(((c)->cx_type & (CXt_EVAL|CXp_REAL))		\
450 			 == (CXt_EVAL|CXp_REAL))
451 #define CxTRYBLOCK(c)	(((c)->cx_type & (CXt_EVAL|CXp_TRYBLOCK))	\
452 			 == (CXt_EVAL|CXp_TRYBLOCK))
453 
454 #define CXINC (cxstack_ix < cxstack_max ? ++cxstack_ix : (cxstack_ix = cxinc()))
455 
456 /*
457 =head1 "Gimme" Values
458 */
459 
460 /*
461 =for apidoc AmU||G_SCALAR
462 Used to indicate scalar context.  See C<GIMME_V>, C<GIMME>, and
463 L<perlcall>.
464 
465 =for apidoc AmU||G_ARRAY
466 Used to indicate list context.  See C<GIMME_V>, C<GIMME> and
467 L<perlcall>.
468 
469 =for apidoc AmU||G_VOID
470 Used to indicate void context.  See C<GIMME_V> and L<perlcall>.
471 
472 =for apidoc AmU||G_DISCARD
473 Indicates that arguments returned from a callback should be discarded.  See
474 L<perlcall>.
475 
476 =for apidoc AmU||G_EVAL
477 
478 Used to force a Perl C<eval> wrapper around a callback.  See
479 L<perlcall>.
480 
481 =for apidoc AmU||G_NOARGS
482 
483 Indicates that no arguments are being sent to a callback.  See
484 L<perlcall>.
485 
486 =cut
487 */
488 
489 #define G_SCALAR	0
490 #define G_ARRAY		1
491 #define G_VOID		128	/* skip this bit when adding flags below */
492 
493 /* extra flags for Perl_call_* routines */
494 #define G_DISCARD	2	/* Call FREETMPS. */
495 #define G_EVAL		4	/* Assume eval {} around subroutine call. */
496 #define G_NOARGS	8	/* Don't construct a @_ array. */
497 #define G_KEEPERR      16	/* Append errors to $@, don't overwrite it */
498 #define G_NODEBUG      32	/* Disable debugging at toplevel.  */
499 #define G_METHOD       64       /* Calling method. */
500 
501 /* flag bits for PL_in_eval */
502 #define EVAL_NULL	0	/* not in an eval */
503 #define EVAL_INEVAL	1	/* some enclosing scope is an eval */
504 #define EVAL_WARNONLY	2	/* used by yywarn() when calling yyerror() */
505 #define EVAL_KEEPERR	4	/* set by Perl_call_sv if G_KEEPERR */
506 #define EVAL_INREQUIRE	8	/* The code is being required. */
507 
508 /* Support for switching (stack and block) contexts.
509  * This ensures magic doesn't invalidate local stack and cx pointers.
510  */
511 
512 #define PERLSI_UNKNOWN		-1
513 #define PERLSI_UNDEF		0
514 #define PERLSI_MAIN		1
515 #define PERLSI_MAGIC		2
516 #define PERLSI_SORT		3
517 #define PERLSI_SIGNAL		4
518 #define PERLSI_OVERLOAD		5
519 #define PERLSI_DESTROY		6
520 #define PERLSI_WARNHOOK		7
521 #define PERLSI_DIEHOOK		8
522 #define PERLSI_REQUIRE		9
523 
524 struct stackinfo {
525     AV *		si_stack;	/* stack for current runlevel */
526     PERL_CONTEXT *	si_cxstack;	/* context stack for runlevel */
527     I32			si_cxix;	/* current context index */
528     I32			si_cxmax;	/* maximum allocated index */
529     I32			si_type;	/* type of runlevel */
530     struct stackinfo *	si_prev;
531     struct stackinfo *	si_next;
532     I32			si_markoff;	/* offset where markstack begins for us.
533 					 * currently used only with DEBUGGING,
534 					 * but not #ifdef-ed for bincompat */
535 };
536 
537 typedef struct stackinfo PERL_SI;
538 
539 #define cxstack		(PL_curstackinfo->si_cxstack)
540 #define cxstack_ix	(PL_curstackinfo->si_cxix)
541 #define cxstack_max	(PL_curstackinfo->si_cxmax)
542 
543 #ifdef DEBUGGING
544 #  define	SET_MARK_OFFSET \
545     PL_curstackinfo->si_markoff = PL_markstack_ptr - PL_markstack
546 #else
547 #  define	SET_MARK_OFFSET NOOP
548 #endif
549 
550 #define PUSHSTACKi(type) \
551     STMT_START {							\
552 	PERL_SI *next = PL_curstackinfo->si_next;			\
553 	if (!next) {							\
554 	    next = new_stackinfo(32, 2048/sizeof(PERL_CONTEXT) - 1);	\
555 	    next->si_prev = PL_curstackinfo;				\
556 	    PL_curstackinfo->si_next = next;				\
557 	}								\
558 	next->si_type = type;						\
559 	next->si_cxix = -1;						\
560 	AvFILLp(next->si_stack) = 0;					\
561 	SWITCHSTACK(PL_curstack,next->si_stack);			\
562 	PL_curstackinfo = next;						\
563 	SET_MARK_OFFSET;						\
564     } STMT_END
565 
566 #define PUSHSTACK PUSHSTACKi(PERLSI_UNKNOWN)
567 
568 /* POPSTACK works with PL_stack_sp, so it may need to be bracketed by
569  * PUTBACK/SPAGAIN to flush/refresh any local SP that may be active */
570 #define POPSTACK \
571     STMT_START {							\
572 	dSP;								\
573 	PERL_SI *prev = PL_curstackinfo->si_prev;			\
574 	if (!prev) {							\
575 	    PerlIO_printf(Perl_error_log, "panic: POPSTACK\n");		\
576 	    my_exit(1);							\
577 	}								\
578 	SWITCHSTACK(PL_curstack,prev->si_stack);			\
579 	/* don't free prev here, free them all at the END{} */		\
580 	PL_curstackinfo = prev;						\
581     } STMT_END
582 
583 #define POPSTACK_TO(s) \
584     STMT_START {							\
585 	while (PL_curstack != s) {					\
586 	    dounwind(-1);						\
587 	    POPSTACK;							\
588 	}								\
589     } STMT_END
590 
591 #define IN_PERL_COMPILETIME	(PL_curcop == &PL_compiling)
592 #define IN_PERL_RUNTIME		(PL_curcop != &PL_compiling)
593 
594