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