Some reordering and one new address for St├ęphane Payrard
[perl.git] / cop.h
1 /*    cop.h
2  *
3  *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
4  *    2000, 2001, 2002, 2003, 2004, 2005, 2006 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 /* A jmpenv packages the state required to perform a proper non-local jump.
17  * Note that there is a start_env initialized when perl starts, and top_env
18  * points to this initially, so top_env should always be non-null.
19  *
20  * Existence of a non-null top_env->je_prev implies it is valid to call
21  * longjmp() at that runlevel (we make sure start_env.je_prev is always
22  * null to ensure this).
23  *
24  * je_mustcatch, when set at any runlevel to TRUE, means eval ops must
25  * establish a local jmpenv to handle exception traps.  Care must be taken
26  * to restore the previous value of je_mustcatch before exiting the
27  * stack frame iff JMPENV_PUSH was not called in that stack frame.
28  * GSAR 97-03-27
29  */
30
31 struct jmpenv {
32     struct jmpenv *     je_prev;
33     Sigjmp_buf          je_buf;         /* only for use if !je_throw */
34     int                 je_ret;         /* last exception thrown */
35     bool                je_mustcatch;   /* need to call longjmp()? */
36 };
37
38 typedef struct jmpenv JMPENV;
39
40 #ifdef OP_IN_REGISTER
41 #define OP_REG_TO_MEM   PL_opsave = op
42 #define OP_MEM_TO_REG   op = PL_opsave
43 #else
44 #define OP_REG_TO_MEM   NOOP
45 #define OP_MEM_TO_REG   NOOP
46 #endif
47
48 /*
49  * How to build the first jmpenv.
50  *
51  * top_env needs to be non-zero. It points to an area
52  * in which longjmp() stuff is stored, as C callstack
53  * info there at least is thread specific this has to
54  * be per-thread. Otherwise a 'die' in a thread gives
55  * that thread the C stack of last thread to do an eval {}!
56  */
57
58 #define JMPENV_BOOTSTRAP \
59     STMT_START {                                \
60         Zero(&PL_start_env, 1, JMPENV);         \
61         PL_start_env.je_ret = -1;               \
62         PL_start_env.je_mustcatch = TRUE;       \
63         PL_top_env = &PL_start_env;             \
64     } STMT_END
65
66 /*
67  *   PERL_FLEXIBLE_EXCEPTIONS
68  * 
69  * All the flexible exceptions code has been removed.
70  * See the following threads for details:
71  *
72  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2004-07/msg00378.html
73  * 
74  * Joshua's original patches (which weren't applied) and discussion:
75  * 
76  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01396.html
77  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01489.html
78  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01491.html
79  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01608.html
80  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg02144.html
81  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg02998.html
82  * 
83  * Chip's reworked patch and discussion:
84  * 
85  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1999-03/msg00520.html
86  * 
87  * The flaw in these patches (which went unnoticed at the time) was
88  * that they moved some code that could potentially die() out of the
89  * region protected by the setjmp()s.  This caused exceptions within
90  * END blocks and such to not be handled by the correct setjmp().
91  * 
92  * The original patches that introduces flexible exceptions were:
93  *
94  *   http://public.activestate.com/cgi-bin/perlbrowse?patch=3386
95  *   http://public.activestate.com/cgi-bin/perlbrowse?patch=5162
96  */
97
98 #define dJMPENV         JMPENV cur_env
99
100 #define JMPENV_PUSH(v) \
101     STMT_START {                                                        \
102         DEBUG_l(Perl_deb(aTHX_ "Setting up jumplevel %p, was %p\n",     \
103                          &cur_env, PL_top_env));                        \
104         cur_env.je_prev = PL_top_env;                                   \
105         OP_REG_TO_MEM;                                                  \
106         cur_env.je_ret = PerlProc_setjmp(cur_env.je_buf, SCOPE_SAVES_SIGNAL_MASK);              \
107         OP_MEM_TO_REG;                                                  \
108         PL_top_env = &cur_env;                                          \
109         cur_env.je_mustcatch = FALSE;                                   \
110         (v) = cur_env.je_ret;                                           \
111     } STMT_END
112
113 #define JMPENV_POP \
114     STMT_START {                                                        \
115         DEBUG_l(Perl_deb(aTHX_ "popping jumplevel was %p, now %p\n",    \
116                          PL_top_env, cur_env.je_prev));                 \
117         PL_top_env = cur_env.je_prev;                                   \
118     } STMT_END
119
120 #define JMPENV_JUMP(v) \
121     STMT_START {                                                \
122         OP_REG_TO_MEM;                                          \
123         if (PL_top_env->je_prev)                                \
124             PerlProc_longjmp(PL_top_env->je_buf, (v));          \
125         if ((v) == 2)                                           \
126             PerlProc_exit(STATUS_EXIT);                         \
127         PerlIO_printf(PerlIO_stderr(), "panic: top_env\n");     \
128         PerlProc_exit(1);                                       \
129     } STMT_END
130
131 #define CATCH_GET               (PL_top_env->je_mustcatch)
132 #define CATCH_SET(v)            (PL_top_env->je_mustcatch = (v))
133
134
135
136 struct cop {
137     BASEOP
138     char *      cop_label;      /* label for this construct */
139 #ifdef USE_ITHREADS
140     char *      cop_stashpv;    /* package line was compiled in */
141     char *      cop_file;       /* file name the following line # is from */
142 #else
143     HV *        cop_stash;      /* package line was compiled in */
144     GV *        cop_filegv;     /* file the following line # is from */
145 #endif
146     U32         cop_seq;        /* parse sequence number */
147     I32         cop_arybase;    /* array base this line was compiled with */
148     line_t      cop_line;       /* line # of this command */
149     SV *        cop_warnings;   /* lexical warnings bitmask */
150     SV *        cop_io;         /* lexical IO defaults */
151 };
152
153 #define Nullcop Null(COP*)
154
155 #ifdef USE_ITHREADS
156 #  define CopFILE(c)            ((c)->cop_file)
157 #  define CopFILEGV(c)          (CopFILE(c) \
158                                  ? gv_fetchfile(CopFILE(c)) : Nullgv)
159                                  
160 #  ifdef NETWARE
161 #    define CopFILE_set(c,pv)   ((c)->cop_file = savepv(pv))
162 #  else
163 #    define CopFILE_set(c,pv)   ((c)->cop_file = savesharedpv(pv))
164 #  endif
165
166 #  define CopFILESV(c)          (CopFILE(c) \
167                                  ? GvSV(gv_fetchfile(CopFILE(c))) : Nullsv)
168 #  define CopFILEAV(c)          (CopFILE(c) \
169                                  ? GvAV(gv_fetchfile(CopFILE(c))) : NULL)
170 #  ifdef DEBUGGING
171 #    define CopFILEAVx(c)       (assert(CopFILE(c)), \
172                                    GvAV(gv_fetchfile(CopFILE(c))))
173 #  else
174 #    define CopFILEAVx(c)       (GvAV(gv_fetchfile(CopFILE(c))))
175 #  endif
176 #  define CopSTASHPV(c)         ((c)->cop_stashpv)
177
178 #  ifdef NETWARE
179 #    define CopSTASHPV_set(c,pv)        ((c)->cop_stashpv = ((pv) ? savepv(pv) : Nullch))
180 #  else
181 #    define CopSTASHPV_set(c,pv)        ((c)->cop_stashpv = savesharedpv(pv))
182 #  endif
183
184 #  define CopSTASH(c)           (CopSTASHPV(c) \
185                                  ? gv_stashpv(CopSTASHPV(c),GV_ADD) : NULL)
186 #  define CopSTASH_set(c,hv)    CopSTASHPV_set(c, (hv) ? HvNAME_get(hv) : Nullch)
187 #  define CopSTASH_eq(c,hv)     ((hv) && stashpv_hvname_match(c,hv))
188 #  ifdef NETWARE
189 #    define CopSTASH_free(c) SAVECOPSTASH_FREE(c)
190 #    define CopFILE_free(c) SAVECOPFILE_FREE(c)
191 #  else
192 #    define CopSTASH_free(c)    PerlMemShared_free(CopSTASHPV(c))
193 #    define CopFILE_free(c)     (PerlMemShared_free(CopFILE(c)),(CopFILE(c) = Nullch))
194 #  endif
195 #else
196 #  define CopFILEGV(c)          ((c)->cop_filegv)
197 #  define CopFILEGV_set(c,gv)   ((c)->cop_filegv = (GV*)SvREFCNT_inc(gv))
198 #  define CopFILE_set(c,pv)     CopFILEGV_set((c), gv_fetchfile(pv))
199 #  define CopFILESV(c)          (CopFILEGV(c) ? GvSV(CopFILEGV(c)) : Nullsv)
200 #  define CopFILEAV(c)          (CopFILEGV(c) ? GvAV(CopFILEGV(c)) : NULL)
201 #  ifdef DEBUGGING
202 #    define CopFILEAVx(c)       (assert(CopFILEGV(c)), GvAV(CopFILEGV(c)))
203 #  else
204 #    define CopFILEAVx(c)       (GvAV(CopFILEGV(c)))
205 # endif
206 #  define CopFILE(c)            (CopFILESV(c) ? SvPVX(CopFILESV(c)) : Nullch)
207 #  define CopSTASH(c)           ((c)->cop_stash)
208 #  define CopSTASH_set(c,hv)    ((c)->cop_stash = (hv))
209 #  define CopSTASHPV(c)         (CopSTASH(c) ? HvNAME_get(CopSTASH(c)) : Nullch)
210    /* cop_stash is not refcounted */
211 #  define CopSTASHPV_set(c,pv)  CopSTASH_set((c), gv_stashpv(pv,GV_ADD))
212 #  define CopSTASH_eq(c,hv)     (CopSTASH(c) == (hv))
213 #  define CopSTASH_free(c)      
214 #  define CopFILE_free(c)       (SvREFCNT_dec(CopFILEGV(c)),(CopFILEGV(c) = Nullgv))
215
216 #endif /* USE_ITHREADS */
217
218 #define CopSTASH_ne(c,hv)       (!CopSTASH_eq(c,hv))
219 #define CopLINE(c)              ((c)->cop_line)
220 #define CopLINE_inc(c)          (++CopLINE(c))
221 #define CopLINE_dec(c)          (--CopLINE(c))
222 #define CopLINE_set(c,l)        (CopLINE(c) = (l))
223
224 /* OutCopFILE() is CopFILE for output (caller, die, warn, etc.) */
225 #ifdef MACOS_TRADITIONAL
226 #  define OutCopFILE(c) MacPerl_MPWFileName(CopFILE(c))
227 #else
228 #  define OutCopFILE(c) CopFILE(c)
229 #endif
230
231 /*
232  * Here we have some enormously heavy (or at least ponderous) wizardry.
233  */
234
235 /* subroutine context */
236 struct block_sub {
237     CV *        cv;
238     GV *        gv;
239     GV *        dfoutgv;
240     AV *        savearray;
241     AV *        argarray;
242     long        olddepth;
243     U8          hasargs;
244     U8          lval;           /* XXX merge lval and hasargs? */
245     PAD         *oldcomppad;
246     OP *        retop;  /* op to execute on exit from sub */
247 };
248
249 /* base for the next two macros. Don't use directly.
250  * Note that the refcnt of the cv is incremented twice;  The CX one is
251  * decremented by LEAVESUB, the other by LEAVE. */
252
253 #define PUSHSUB_BASE(cx)                                                \
254         cx->blk_sub.cv = cv;                                            \
255         cx->blk_sub.olddepth = CvDEPTH(cv);                             \
256         cx->blk_sub.hasargs = hasargs;                                  \
257         cx->blk_sub.retop = Nullop;                                             \
258         if (!CvDEPTH(cv)) {                                             \
259             (void)SvREFCNT_inc(cv);                                     \
260             (void)SvREFCNT_inc(cv);                                     \
261             SAVEFREESV(cv);                                             \
262         }
263
264
265 #define PUSHSUB(cx)                                                     \
266         PUSHSUB_BASE(cx)                                                \
267         cx->blk_sub.lval = PL_op->op_private &                          \
268                               (OPpLVAL_INTRO|OPpENTERSUB_INARGS);
269
270 /* variant for use by OP_DBSTATE, where op_private holds hint bits */
271 #define PUSHSUB_DB(cx)                                                  \
272         PUSHSUB_BASE(cx)                                                \
273         cx->blk_sub.lval = 0;
274
275
276 #define PUSHFORMAT(cx)                                                  \
277         cx->blk_sub.cv = cv;                                            \
278         cx->blk_sub.gv = gv;                                            \
279         cx->blk_sub.retop = Nullop;                                     \
280         cx->blk_sub.hasargs = 0;                                        \
281         cx->blk_sub.dfoutgv = PL_defoutgv;                              \
282         (void)SvREFCNT_inc(cx->blk_sub.dfoutgv)
283
284 #define POP_SAVEARRAY()                                         \
285     STMT_START {                                                        \
286         SvREFCNT_dec(GvAV(PL_defgv));                                   \
287         GvAV(PL_defgv) = cx->blk_sub.savearray;                         \
288     } STMT_END
289
290 /* junk in @_ spells trouble when cloning CVs and in pp_caller(), so don't
291  * leave any (a fast av_clear(ary), basically) */
292 #define CLEAR_ARGARRAY(ary) \
293     STMT_START {                                                        \
294         AvMAX(ary) += AvARRAY(ary) - AvALLOC(ary);                      \
295         SvPV_set(ary, (char*)AvALLOC(ary));                             \
296         AvFILLp(ary) = -1;                                              \
297     } STMT_END
298
299 #define POPSUB(cx,sv)                                                   \
300     STMT_START {                                                        \
301         if (cx->blk_sub.hasargs) {                                      \
302             POP_SAVEARRAY();                                            \
303             /* abandon @_ if it got reified */                          \
304             if (AvREAL(cx->blk_sub.argarray)) {                         \
305                 SSize_t fill = AvFILLp(cx->blk_sub.argarray);           \
306                 SvREFCNT_dec(cx->blk_sub.argarray);                     \
307                 cx->blk_sub.argarray = newAV();                         \
308                 av_extend(cx->blk_sub.argarray, fill);                  \
309                 AvREIFY_only(cx->blk_sub.argarray);                     \
310                 CX_CURPAD_SV(cx->blk_sub, 0) = (SV*)cx->blk_sub.argarray;       \
311             }                                                           \
312             else {                                                      \
313                 CLEAR_ARGARRAY(cx->blk_sub.argarray);                   \
314             }                                                           \
315         }                                                               \
316         sv = (SV*)cx->blk_sub.cv;                                       \
317         if (sv && (CvDEPTH((CV*)sv) = cx->blk_sub.olddepth))            \
318             sv = Nullsv;                                                \
319     } STMT_END
320
321 #define LEAVESUB(sv)                                                    \
322     STMT_START {                                                        \
323         if (sv)                                                         \
324             SvREFCNT_dec(sv);                                           \
325     } STMT_END
326
327 #define POPFORMAT(cx)                                                   \
328         setdefout(cx->blk_sub.dfoutgv);                                 \
329         SvREFCNT_dec(cx->blk_sub.dfoutgv);
330
331 /* eval context */
332 struct block_eval {
333     I32         old_in_eval;
334     I32         old_op_type;
335     SV *        old_namesv;
336     OP *        old_eval_root;
337     SV *        cur_text;
338     CV *        cv;
339     OP *        retop;  /* op to execute on exit from eval */
340     JMPENV *    cur_top_env; /* value of PL_top_env when eval CX created */
341 };
342
343 #define PUSHEVAL(cx,n,fgv)                                              \
344     STMT_START {                                                        \
345         cx->blk_eval.old_in_eval = PL_in_eval;                          \
346         cx->blk_eval.old_op_type = PL_op->op_type;                      \
347         cx->blk_eval.old_namesv = (n ? newSVpv(n,0) : Nullsv);          \
348         cx->blk_eval.old_eval_root = PL_eval_root;                      \
349         cx->blk_eval.cur_text = PL_linestr;                             \
350         cx->blk_eval.cv = Nullcv; /* set by doeval(), as applicable */  \
351         cx->blk_eval.retop = Nullop;                                    \
352         cx->blk_eval.cur_top_env = PL_top_env;                          \
353     } STMT_END
354
355 #define POPEVAL(cx)                                                     \
356     STMT_START {                                                        \
357         PL_in_eval = cx->blk_eval.old_in_eval;                          \
358         optype = cx->blk_eval.old_op_type;                              \
359         PL_eval_root = cx->blk_eval.old_eval_root;                      \
360         if (cx->blk_eval.old_namesv)                                    \
361             sv_2mortal(cx->blk_eval.old_namesv);                        \
362     } STMT_END
363
364 /* loop context */
365 struct block_loop {
366     char *      label;
367     I32         resetsp;
368     OP *        redo_op;
369     OP *        next_op;
370     OP *        last_op;
371 #ifdef USE_ITHREADS
372     void *      iterdata;
373     PAD         *oldcomppad;
374 #else
375     SV **       itervar;
376 #endif
377     SV *        itersave;
378     SV *        iterlval;
379     AV *        iterary;
380     IV          iterix;
381     IV          itermax;
382 };
383
384 #ifdef USE_ITHREADS
385 #  define CxITERVAR(c)                                                  \
386         ((c)->blk_loop.iterdata                                         \
387          ? (CxPADLOOP(cx)                                               \
388             ? &CX_CURPAD_SV( (c)->blk_loop,                             \
389                     INT2PTR(PADOFFSET, (c)->blk_loop.iterdata))         \
390             : &GvSV((GV*)(c)->blk_loop.iterdata))                       \
391          : (SV**)NULL)
392 #  define CX_ITERDATA_SET(cx,idata)                                     \
393         CX_CURPAD_SAVE(cx->blk_loop);                                   \
394         if ((cx->blk_loop.iterdata = (idata)))                          \
395             cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));       \
396         else                                                            \
397             cx->blk_loop.itersave = Nullsv;
398 #else
399 #  define CxITERVAR(c)          ((c)->blk_loop.itervar)
400 #  define CX_ITERDATA_SET(cx,ivar)                                      \
401         if ((cx->blk_loop.itervar = (SV**)(ivar)))                      \
402             cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));       \
403         else                                                            \
404             cx->blk_loop.itersave = Nullsv;
405 #endif
406
407 #define PUSHLOOP(cx, dat, s)                                            \
408         cx->blk_loop.label = PL_curcop->cop_label;                      \
409         cx->blk_loop.resetsp = s - PL_stack_base;                       \
410         cx->blk_loop.redo_op = cLOOP->op_redoop;                        \
411         cx->blk_loop.next_op = cLOOP->op_nextop;                        \
412         cx->blk_loop.last_op = cLOOP->op_lastop;                        \
413         cx->blk_loop.iterlval = Nullsv;                                 \
414         cx->blk_loop.iterary = NULL;                                    \
415         cx->blk_loop.iterix = -1;                                       \
416         CX_ITERDATA_SET(cx,dat);
417
418 #define POPLOOP(cx)                                                     \
419         SvREFCNT_dec(cx->blk_loop.iterlval);                            \
420         if (CxITERVAR(cx)) {                                            \
421             if (SvPADMY(cx->blk_loop.itersave)) {                       \
422                 SV **s_v_p = CxITERVAR(cx);                             \
423                 sv_2mortal(*s_v_p);                                     \
424                 *s_v_p = cx->blk_loop.itersave;                         \
425             }                                                           \
426             else {                                                      \
427                 SvREFCNT_dec(cx->blk_loop.itersave);                    \
428             }                                                           \
429         }                                                               \
430         if (cx->blk_loop.iterary && cx->blk_loop.iterary != PL_curstack)\
431             SvREFCNT_dec(cx->blk_loop.iterary);
432
433 /* given/when context */
434 struct block_givwhen {
435         OP *leave_op;
436 };
437
438 #define PUSHGIVEN(cx)                                                   \
439         cx->blk_givwhen.leave_op = cLOGOP->op_other;
440
441 #define PUSHWHEN PUSHGIVEN
442
443 /* context common to subroutines, evals and loops */
444 struct block {
445     I32         blku_oldsp;     /* stack pointer to copy stuff down to */
446     COP *       blku_oldcop;    /* old curcop pointer */
447     I32         blku_oldmarksp; /* mark stack index */
448     I32         blku_oldscopesp;        /* scope stack index */
449     PMOP *      blku_oldpm;     /* values of pattern match vars */
450     U8          blku_gimme;     /* is this block running in list context? */
451
452     union {
453         struct block_sub        blku_sub;
454         struct block_eval       blku_eval;
455         struct block_loop       blku_loop;
456         struct block_givwhen    blku_givwhen;
457     } blk_u;
458 };
459 #define blk_oldsp       cx_u.cx_blk.blku_oldsp
460 #define blk_oldcop      cx_u.cx_blk.blku_oldcop
461 #define blk_oldmarksp   cx_u.cx_blk.blku_oldmarksp
462 #define blk_oldscopesp  cx_u.cx_blk.blku_oldscopesp
463 #define blk_oldpm       cx_u.cx_blk.blku_oldpm
464 #define blk_gimme       cx_u.cx_blk.blku_gimme
465 #define blk_sub         cx_u.cx_blk.blk_u.blku_sub
466 #define blk_eval        cx_u.cx_blk.blk_u.blku_eval
467 #define blk_loop        cx_u.cx_blk.blk_u.blku_loop
468 #define blk_givwhen     cx_u.cx_blk.blk_u.blku_givwhen
469
470 /* Enter a block. */
471 #define PUSHBLOCK(cx,t,sp) CXINC, cx = &cxstack[cxstack_ix],            \
472         cx->cx_type             = t,                                    \
473         cx->blk_oldsp           = sp - PL_stack_base,                   \
474         cx->blk_oldcop          = PL_curcop,                            \
475         cx->blk_oldmarksp       = PL_markstack_ptr - PL_markstack,      \
476         cx->blk_oldscopesp      = PL_scopestack_ix,                     \
477         cx->blk_oldpm           = PL_curpm,                             \
478         cx->blk_gimme           = (U8)gimme;                            \
479         DEBUG_l( PerlIO_printf(Perl_debug_log, "Entering block %ld, type %s\n", \
480                     (long)cxstack_ix, PL_block_type[CxTYPE(cx)]); )
481
482 /* Exit a block (RETURN and LAST). */
483 #define POPBLOCK(cx,pm) cx = &cxstack[cxstack_ix--],                    \
484         newsp            = PL_stack_base + cx->blk_oldsp,               \
485         PL_curcop        = cx->blk_oldcop,                              \
486         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
487         PL_scopestack_ix = cx->blk_oldscopesp,                          \
488         pm               = cx->blk_oldpm,                               \
489         gimme            = cx->blk_gimme;                               \
490         DEBUG_SCOPE("POPBLOCK");                                        \
491         DEBUG_l( PerlIO_printf(Perl_debug_log, "Leaving block %ld, type %s\n",          \
492                     (long)cxstack_ix+1,PL_block_type[CxTYPE(cx)]); )
493
494 /* Continue a block elsewhere (NEXT and REDO). */
495 #define TOPBLOCK(cx) cx  = &cxstack[cxstack_ix],                        \
496         PL_stack_sp      = PL_stack_base + cx->blk_oldsp,               \
497         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
498         PL_scopestack_ix = cx->blk_oldscopesp,                          \
499         PL_curpm         = cx->blk_oldpm;                               \
500         DEBUG_SCOPE("TOPBLOCK");
501
502 /* substitution context */
503 struct subst {
504     I32         sbu_iters;
505     I32         sbu_maxiters;
506     I32         sbu_rflags;
507     I32         sbu_oldsave;
508     bool        sbu_once;
509     bool        sbu_rxtainted;
510     char *      sbu_orig;
511     SV *        sbu_dstr;
512     SV *        sbu_targ;
513     char *      sbu_s;
514     char *      sbu_m;
515     char *      sbu_strend;
516     void *      sbu_rxres;
517     REGEXP *    sbu_rx;
518 };
519 #define sb_iters        cx_u.cx_subst.sbu_iters
520 #define sb_maxiters     cx_u.cx_subst.sbu_maxiters
521 #define sb_rflags       cx_u.cx_subst.sbu_rflags
522 #define sb_oldsave      cx_u.cx_subst.sbu_oldsave
523 #define sb_once         cx_u.cx_subst.sbu_once
524 #define sb_rxtainted    cx_u.cx_subst.sbu_rxtainted
525 #define sb_orig         cx_u.cx_subst.sbu_orig
526 #define sb_dstr         cx_u.cx_subst.sbu_dstr
527 #define sb_targ         cx_u.cx_subst.sbu_targ
528 #define sb_s            cx_u.cx_subst.sbu_s
529 #define sb_m            cx_u.cx_subst.sbu_m
530 #define sb_strend       cx_u.cx_subst.sbu_strend
531 #define sb_rxres        cx_u.cx_subst.sbu_rxres
532 #define sb_rx           cx_u.cx_subst.sbu_rx
533
534 #define PUSHSUBST(cx) CXINC, cx = &cxstack[cxstack_ix],                 \
535         cx->sb_iters            = iters,                                \
536         cx->sb_maxiters         = maxiters,                             \
537         cx->sb_rflags           = r_flags,                              \
538         cx->sb_oldsave          = oldsave,                              \
539         cx->sb_once             = once,                                 \
540         cx->sb_rxtainted        = rxtainted,                            \
541         cx->sb_orig             = orig,                                 \
542         cx->sb_dstr             = dstr,                                 \
543         cx->sb_targ             = targ,                                 \
544         cx->sb_s                = s,                                    \
545         cx->sb_m                = m,                                    \
546         cx->sb_strend           = strend,                               \
547         cx->sb_rxres            = Null(void*),                          \
548         cx->sb_rx               = rx,                                   \
549         cx->cx_type             = CXt_SUBST;                            \
550         rxres_save(&cx->sb_rxres, rx)
551
552 #define POPSUBST(cx) cx = &cxstack[cxstack_ix--];                       \
553         rxres_free(&cx->sb_rxres)
554
555 struct context {
556     U32         cx_type;        /* what kind of context this is */
557     union {
558         struct block    cx_blk;
559         struct subst    cx_subst;
560     } cx_u;
561 };
562
563 #define CXTYPEMASK      0xff
564 #define CXt_NULL        0
565 #define CXt_SUB         1
566 #define CXt_EVAL        2
567 #define CXt_LOOP        3
568 #define CXt_SUBST       4
569 #define CXt_BLOCK       5
570 #define CXt_FORMAT      6
571 #define CXt_GIVEN       7
572 #define CXt_WHEN        8
573
574 /* private flags for CXt_SUB and CXt_NULL */
575 #define CXp_MULTICALL   0x00000400      /* part of a multicall (so don't
576                                            tear down context on exit). */ 
577
578 /* private flags for CXt_EVAL */
579 #define CXp_REAL        0x00000100      /* truly eval'', not a lookalike */
580 #define CXp_TRYBLOCK    0x00000200      /* eval{}, not eval'' or similar */
581
582 /* private flags for CXt_LOOP */
583 #define CXp_FOREACH     0x00000200      /* a foreach loop */
584 #define CXp_FOR_DEF     0x00000400      /* foreach using $_ */
585 #ifdef USE_ITHREADS
586 #  define CXp_PADVAR    0x00000100      /* itervar lives on pad, iterdata
587                                            has pad offset; if not set,
588                                            iterdata holds GV* */
589 #  define CxPADLOOP(c)  (((c)->cx_type & (CXt_LOOP|CXp_PADVAR))         \
590                          == (CXt_LOOP|CXp_PADVAR))
591 #endif
592
593 #define CxTYPE(c)       ((c)->cx_type & CXTYPEMASK)
594 #define CxMULTICALL(c)  (((c)->cx_type & CXp_MULTICALL)                 \
595                          == CXp_MULTICALL)
596 #define CxREALEVAL(c)   (((c)->cx_type & (CXt_EVAL|CXp_REAL))           \
597                          == (CXt_EVAL|CXp_REAL))
598 #define CxTRYBLOCK(c)   (((c)->cx_type & (CXt_EVAL|CXp_TRYBLOCK))       \
599                          == (CXt_EVAL|CXp_TRYBLOCK))
600 #define CxFOREACH(c)    (((c)->cx_type & (CXt_LOOP|CXp_FOREACH))        \
601                          == (CXt_LOOP|CXp_FOREACH))
602 #define CxFOREACHDEF(c) (((c)->cx_type & (CXt_LOOP|CXp_FOREACH|CXp_FOR_DEF))\
603                          == (CXt_LOOP|CXp_FOREACH|CXp_FOR_DEF))
604
605 #define CXINC (cxstack_ix < cxstack_max ? ++cxstack_ix : (cxstack_ix = cxinc()))
606
607 /* 
608 =head1 "Gimme" Values
609 */
610
611 /*
612 =for apidoc AmU||G_SCALAR
613 Used to indicate scalar context.  See C<GIMME_V>, C<GIMME>, and
614 L<perlcall>.
615
616 =for apidoc AmU||G_ARRAY
617 Used to indicate list context.  See C<GIMME_V>, C<GIMME> and
618 L<perlcall>.
619
620 =for apidoc AmU||G_VOID
621 Used to indicate void context.  See C<GIMME_V> and L<perlcall>.
622
623 =for apidoc AmU||G_DISCARD
624 Indicates that arguments returned from a callback should be discarded.  See
625 L<perlcall>.
626
627 =for apidoc AmU||G_EVAL
628
629 Used to force a Perl C<eval> wrapper around a callback.  See
630 L<perlcall>.
631
632 =for apidoc AmU||G_NOARGS
633
634 Indicates that no arguments are being sent to a callback.  See
635 L<perlcall>.
636
637 =cut
638 */
639
640 #define G_SCALAR        0
641 #define G_ARRAY         1
642 #define G_VOID          128     /* skip this bit when adding flags below */
643
644 /* extra flags for Perl_call_* routines */
645 #define G_DISCARD       2       /* Call FREETMPS. */
646 #define G_EVAL          4       /* Assume eval {} around subroutine call. */
647 #define G_NOARGS        8       /* Don't construct a @_ array. */
648 #define G_KEEPERR      16       /* Append errors to $@, don't overwrite it */
649 #define G_NODEBUG      32       /* Disable debugging at toplevel.  */
650 #define G_METHOD       64       /* Calling method. */
651
652 /* flag bits for PL_in_eval */
653 #define EVAL_NULL       0       /* not in an eval */
654 #define EVAL_INEVAL     1       /* some enclosing scope is an eval */
655 #define EVAL_WARNONLY   2       /* used by yywarn() when calling yyerror() */
656 #define EVAL_KEEPERR    4       /* set by Perl_call_sv if G_KEEPERR */
657 #define EVAL_INREQUIRE  8       /* The code is being required. */
658
659 /* Support for switching (stack and block) contexts.
660  * This ensures magic doesn't invalidate local stack and cx pointers.
661  */
662
663 #define PERLSI_UNKNOWN          -1
664 #define PERLSI_UNDEF            0
665 #define PERLSI_MAIN             1
666 #define PERLSI_MAGIC            2
667 #define PERLSI_SORT             3
668 #define PERLSI_SIGNAL           4
669 #define PERLSI_OVERLOAD         5
670 #define PERLSI_DESTROY          6
671 #define PERLSI_WARNHOOK         7
672 #define PERLSI_DIEHOOK          8
673 #define PERLSI_REQUIRE          9
674
675 struct stackinfo {
676     AV *                si_stack;       /* stack for current runlevel */
677     PERL_CONTEXT *      si_cxstack;     /* context stack for runlevel */
678     I32                 si_cxix;        /* current context index */
679     I32                 si_cxmax;       /* maximum allocated index */
680     I32                 si_type;        /* type of runlevel */
681     struct stackinfo *  si_prev;
682     struct stackinfo *  si_next;
683     I32                 si_markoff;     /* offset where markstack begins for us.
684                                          * currently used only with DEBUGGING,
685                                          * but not #ifdef-ed for bincompat */
686 };
687
688 typedef struct stackinfo PERL_SI;
689
690 #define cxstack         (PL_curstackinfo->si_cxstack)
691 #define cxstack_ix      (PL_curstackinfo->si_cxix)
692 #define cxstack_max     (PL_curstackinfo->si_cxmax)
693
694 #ifdef DEBUGGING
695 #  define       SET_MARK_OFFSET \
696     PL_curstackinfo->si_markoff = PL_markstack_ptr - PL_markstack
697 #else
698 #  define       SET_MARK_OFFSET NOOP
699 #endif
700
701 #define PUSHSTACKi(type) \
702     STMT_START {                                                        \
703         PERL_SI *next = PL_curstackinfo->si_next;                       \
704         if (!next) {                                                    \
705             next = new_stackinfo(32, 2048/sizeof(PERL_CONTEXT) - 1);    \
706             next->si_prev = PL_curstackinfo;                            \
707             PL_curstackinfo->si_next = next;                            \
708         }                                                               \
709         next->si_type = type;                                           \
710         next->si_cxix = -1;                                             \
711         AvFILLp(next->si_stack) = 0;                                    \
712         SWITCHSTACK(PL_curstack,next->si_stack);                        \
713         PL_curstackinfo = next;                                         \
714         SET_MARK_OFFSET;                                                \
715     } STMT_END
716
717 #define PUSHSTACK PUSHSTACKi(PERLSI_UNKNOWN)
718
719 /* POPSTACK works with PL_stack_sp, so it may need to be bracketed by
720  * PUTBACK/SPAGAIN to flush/refresh any local SP that may be active */
721 #define POPSTACK \
722     STMT_START {                                                        \
723         dSP;                                                            \
724         PERL_SI * const prev = PL_curstackinfo->si_prev;                \
725         if (!prev) {                                                    \
726             PerlIO_printf(Perl_error_log, "panic: POPSTACK\n");         \
727             my_exit(1);                                                 \
728         }                                                               \
729         SWITCHSTACK(PL_curstack,prev->si_stack);                        \
730         /* don't free prev here, free them all at the END{} */          \
731         PL_curstackinfo = prev;                                         \
732     } STMT_END
733
734 #define POPSTACK_TO(s) \
735     STMT_START {                                                        \
736         while (PL_curstack != s) {                                      \
737             dounwind(-1);                                               \
738             POPSTACK;                                                   \
739         }                                                               \
740     } STMT_END
741
742 #define IN_PERL_COMPILETIME     (PL_curcop == &PL_compiling)
743 #define IN_PERL_RUNTIME         (PL_curcop != &PL_compiling)
744
745 /*
746 =head1 Multicall Functions
747
748 =for apidoc Ams||dMULTICALL
749 Declare local variables for a multicall. See L<perlcall/Lightweight Callbacks>.
750
751 =for apidoc Ams||PUSH_MULTICALL
752 Opening bracket for a lightweight callback.
753 See L<perlcall/Lightweight Callbacks>.
754
755 =for apidoc Ams||MULTICALL
756 Make a lightweight callback. See L<perlcall/Lightweight Callbacks>.
757
758 =for apidoc Ams||POP_MULTICALL
759 Closing bracket for a lightweight callback.
760 See L<perlcall/Lightweight Callbacks>.
761
762 =cut
763 */
764
765 #define dMULTICALL \
766     SV **newsp;                 /* set by POPBLOCK */                   \
767     PERL_CONTEXT *cx;                                                   \
768     CV *multicall_cv;                                                   \
769     OP *multicall_cop;                                                  \
770     bool multicall_oldcatch;                                            \
771     U8 hasargs = 0              /* used by PUSHSUB */
772
773 #define PUSH_MULTICALL(the_cv) \
774     STMT_START {                                                        \
775         CV * const _nOnclAshIngNamE_ = the_cv;                          \
776         CV * const cv = _nOnclAshIngNamE_;                              \
777         AV * const padlist = CvPADLIST(cv);                             \
778         ENTER;                                                          \
779         multicall_oldcatch = CATCH_GET;                                 \
780         SAVETMPS; SAVEVPTR(PL_op);                                      \
781         CATCH_SET(TRUE);                                                \
782         PUSHBLOCK(cx, CXt_SUB|CXp_MULTICALL, PL_stack_sp);              \
783         PUSHSUB(cx);                                                    \
784         if (++CvDEPTH(cv) >= 2) {                                       \
785             PERL_STACK_OVERFLOW_CHECK();                                \
786             Perl_pad_push(aTHX_ padlist, CvDEPTH(cv));                  \
787         }                                                               \
788         SAVECOMPPAD();                                                  \
789         PAD_SET_CUR_NOSAVE(padlist, CvDEPTH(cv));                       \
790         multicall_cv = cv;                                              \
791         multicall_cop = CvSTART(cv);                                    \
792     } STMT_END
793
794 #define MULTICALL \
795     STMT_START {                                                        \
796         PL_op = multicall_cop;                                          \
797         CALLRUNOPS(aTHX);                                               \
798     } STMT_END
799
800 #define POP_MULTICALL \
801     STMT_START {                                                        \
802         LEAVESUB(multicall_cv);                                         \
803         CvDEPTH(multicall_cv)--;                                        \
804         POPBLOCK(cx,PL_curpm);                                          \
805         CATCH_SET(multicall_oldcatch);                                  \
806         LEAVE;                                                          \
807     } STMT_END