Avoid a possible race condition where a parallel make might
[p5sagit/p5-mst-13.2.git] / cop.h
1 /*    cop.h
2  *
3  *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
4  *    2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 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 two ops OP_NEXTSTATE and OP_DBSTATE,
10  * 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 at %s:%d\n",    \
103                          (void*)&cur_env, (void*)PL_top_env,                    \
104                          __FILE__, __LINE__));                                  \
105         cur_env.je_prev = PL_top_env;                                   \
106         OP_REG_TO_MEM;                                                  \
107         cur_env.je_ret = PerlProc_setjmp(cur_env.je_buf, SCOPE_SAVES_SIGNAL_MASK);              \
108         OP_MEM_TO_REG;                                                  \
109         PL_top_env = &cur_env;                                          \
110         cur_env.je_mustcatch = FALSE;                                   \
111         (v) = cur_env.je_ret;                                           \
112     } STMT_END
113
114 #define JMPENV_POP \
115     STMT_START {                                                        \
116         DEBUG_l(Perl_deb(aTHX_ "popping jumplevel was %p, now %p at %s:%d\n",   \
117                          (void*)PL_top_env, (void*)cur_env.je_prev,             \
118                          __FILE__, __LINE__));                                  \
119         assert(PL_top_env == &cur_env);                                 \
120         PL_top_env = cur_env.je_prev;                                   \
121     } STMT_END
122
123 #define JMPENV_JUMP(v) \
124     STMT_START {                                                \
125         OP_REG_TO_MEM;                                          \
126         if (PL_top_env->je_prev)                                \
127             PerlProc_longjmp(PL_top_env->je_buf, (v));          \
128         if ((v) == 2)                                           \
129             PerlProc_exit(STATUS_EXIT);                         \
130         PerlIO_printf(PerlIO_stderr(), "panic: top_env\n");     \
131         PerlProc_exit(1);                                       \
132     } STMT_END
133
134 #define CATCH_GET               (PL_top_env->je_mustcatch)
135 #define CATCH_SET(v)            (PL_top_env->je_mustcatch = (v))
136
137
138 #include "mydtrace.h"
139
140 struct cop {
141     BASEOP
142     /* On LP64 putting this here takes advantage of the fact that BASEOP isn't
143        an exact multiple of 8 bytes to save structure padding.  */
144     line_t      cop_line;       /* line # of this command */
145     /* label for this construct is now stored in cop_hints_hash */
146 #ifdef USE_ITHREADS
147     char *      cop_stashpv;    /* package line was compiled in */
148     char *      cop_file;       /* file name the following line # is from */
149 #else
150     HV *        cop_stash;      /* package line was compiled in */
151     GV *        cop_filegv;     /* file the following line # is from */
152 #endif
153     U32         cop_hints;      /* hints bits from pragmata */
154     U32         cop_seq;        /* parse sequence number */
155     /* Beware. mg.c and warnings.pl assume the type of this is STRLEN *:  */
156     STRLEN *    cop_warnings;   /* lexical warnings bitmask */
157     /* compile time state of %^H.  See the comment in op.c for how this is
158        used to recreate a hash to return from caller.  */
159     struct refcounted_he * cop_hints_hash;
160 };
161
162 #ifdef USE_ITHREADS
163 #  define CopFILE(c)            ((c)->cop_file)
164 #  define CopFILEGV(c)          (CopFILE(c) \
165                                  ? gv_fetchfile(CopFILE(c)) : NULL)
166                                  
167 #  ifdef NETWARE
168 #    define CopFILE_set(c,pv)   ((c)->cop_file = savepv(pv))
169 #    define CopFILE_setn(c,pv,l)  ((c)->cop_file = savepv((pv),(l)))
170 #  else
171 #    define CopFILE_set(c,pv)   ((c)->cop_file = savesharedpv(pv))
172 #    define CopFILE_setn(c,pv,l)  ((c)->cop_file = savesharedpvn((pv),(l)))
173 #  endif
174
175 #  define CopFILESV(c)          (CopFILE(c) \
176                                  ? GvSV(gv_fetchfile(CopFILE(c))) : NULL)
177 #  define CopFILEAV(c)          (CopFILE(c) \
178                                  ? GvAV(gv_fetchfile(CopFILE(c))) : NULL)
179 #  ifdef DEBUGGING
180 #    define CopFILEAVx(c)       (assert(CopFILE(c)), \
181                                    GvAV(gv_fetchfile(CopFILE(c))))
182 #  else
183 #    define CopFILEAVx(c)       (GvAV(gv_fetchfile(CopFILE(c))))
184 #  endif
185 #  define CopSTASHPV(c)         ((c)->cop_stashpv)
186
187 #  ifdef NETWARE
188 #    define CopSTASHPV_set(c,pv)        ((c)->cop_stashpv = ((pv) ? savepv(pv) : NULL))
189 #  else
190 #    define CopSTASHPV_set(c,pv)        ((c)->cop_stashpv = savesharedpv(pv))
191 #  endif
192
193 #  define CopSTASH(c)           (CopSTASHPV(c) \
194                                  ? gv_stashpv(CopSTASHPV(c),GV_ADD) : NULL)
195 #  define CopSTASH_set(c,hv)    CopSTASHPV_set(c, (hv) ? HvNAME_get(hv) : NULL)
196 #  define CopSTASH_eq(c,hv)     ((hv) && stashpv_hvname_match(c,hv))
197 #  ifdef NETWARE
198 #    define CopSTASH_free(c) SAVECOPSTASH_FREE(c)
199 #    define CopFILE_free(c) SAVECOPFILE_FREE(c)
200 #  else
201 #    define CopSTASH_free(c)    PerlMemShared_free(CopSTASHPV(c))
202 #    define CopFILE_free(c)     (PerlMemShared_free(CopFILE(c)),(CopFILE(c) = NULL))
203 #  endif
204 #else
205 #  define CopFILEGV(c)          ((c)->cop_filegv)
206 #  define CopFILEGV_set(c,gv)   ((c)->cop_filegv = (GV*)SvREFCNT_inc(gv))
207 #  define CopFILE_set(c,pv)     CopFILEGV_set((c), gv_fetchfile(pv))
208 #  define CopFILE_setn(c,pv,l)  CopFILEGV_set((c), gv_fetchfile_flags((pv),(l),0))
209 #  define CopFILESV(c)          (CopFILEGV(c) ? GvSV(CopFILEGV(c)) : NULL)
210 #  define CopFILEAV(c)          (CopFILEGV(c) ? GvAV(CopFILEGV(c)) : NULL)
211 #  ifdef DEBUGGING
212 #    define CopFILEAVx(c)       (assert(CopFILEGV(c)), GvAV(CopFILEGV(c)))
213 #  else
214 #    define CopFILEAVx(c)       (GvAV(CopFILEGV(c)))
215 # endif
216 #  define CopFILE(c)            (CopFILEGV(c) && GvSV(CopFILEGV(c)) \
217                                     ? SvPVX(GvSV(CopFILEGV(c))) : NULL)
218 #  define CopSTASH(c)           ((c)->cop_stash)
219 #  define CopSTASH_set(c,hv)    ((c)->cop_stash = (hv))
220 #  define CopSTASHPV(c)         (CopSTASH(c) ? HvNAME_get(CopSTASH(c)) : NULL)
221    /* cop_stash is not refcounted */
222 #  define CopSTASHPV_set(c,pv)  CopSTASH_set((c), gv_stashpv(pv,GV_ADD))
223 #  define CopSTASH_eq(c,hv)     (CopSTASH(c) == (hv))
224 #  define CopSTASH_free(c)      
225 #  define CopFILE_free(c)       (SvREFCNT_dec(CopFILEGV(c)),(CopFILEGV(c) = NULL))
226
227 #endif /* USE_ITHREADS */
228 #define CopLABEL(c)  Perl_fetch_cop_label(aTHX_ (c)->cop_hints_hash, NULL, NULL)
229 #define CopLABEL_alloc(pv)      ((pv)?savepv(pv):NULL)
230
231 #define CopSTASH_ne(c,hv)       (!CopSTASH_eq(c,hv))
232 #define CopLINE(c)              ((c)->cop_line)
233 #define CopLINE_inc(c)          (++CopLINE(c))
234 #define CopLINE_dec(c)          (--CopLINE(c))
235 #define CopLINE_set(c,l)        (CopLINE(c) = (l))
236
237 /* OutCopFILE() is CopFILE for output (caller, die, warn, etc.) */
238 #define OutCopFILE(c) CopFILE(c)
239
240 /* If $[ is non-zero, it's stored in cop_hints under the key "$[", and
241    HINT_ARYBASE is set to indicate this.
242    Setting it is ineficient due to the need to create 2 mortal SVs, but as
243    using $[ is highly discouraged, no sane Perl code will be using it.  */
244 #define CopARYBASE_get(c)       \
245         ((CopHINTS_get(c) & HINT_ARYBASE)                               \
246          ? SvIV(Perl_refcounted_he_fetch(aTHX_ (c)->cop_hints_hash, 0,  \
247                                          "$[", 2, 0, 0))                \
248          : 0)
249 #define CopARYBASE_set(c, b) STMT_START { \
250         if (b || ((c)->cop_hints & HINT_ARYBASE)) {                     \
251             (c)->cop_hints |= HINT_ARYBASE;                             \
252             if ((c) == &PL_compiling) {                                 \
253                 SV *val = newSViv(b);                                   \
254                 (void)hv_stores(GvHV(PL_hintgv), "$[", val);            \
255                 mg_set(val);                                            \
256                 PL_hints |= HINT_ARYBASE;                               \
257             } else {                                                    \
258                 (c)->cop_hints_hash                                     \
259                    = Perl_refcounted_he_new(aTHX_ (c)->cop_hints_hash,  \
260                                         newSVpvs_flags("$[", SVs_TEMP), \
261                                         sv_2mortal(newSViv(b)));        \
262             }                                                           \
263         }                                                               \
264     } STMT_END
265
266 /* FIXME NATIVE_HINTS if this is changed from op_private (see perl.h)  */
267 #define CopHINTS_get(c)         ((c)->cop_hints + 0)
268 #define CopHINTS_set(c, h)      STMT_START {                            \
269                                     (c)->cop_hints = (h);               \
270                                 } STMT_END
271
272 /*
273  * Here we have some enormously heavy (or at least ponderous) wizardry.
274  */
275
276 /* subroutine context */
277 struct block_sub {
278     OP *        retop;  /* op to execute on exit from sub */
279     /* Above here is the same for sub, format and eval.  */
280     CV *        cv;
281     /* Above here is the same for sub and format.  */
282     AV *        savearray;
283     AV *        argarray;
284     I32         olddepth;
285     PAD         *oldcomppad;
286 };
287
288
289 /* format context */
290 struct block_format {
291     OP *        retop;  /* op to execute on exit from sub */
292     /* Above here is the same for sub, format and eval.  */
293     CV *        cv;
294     /* Above here is the same for sub and format.  */
295     GV *        gv;
296     GV *        dfoutgv;
297 };
298
299 /* base for the next two macros. Don't use directly.
300  * Note that the refcnt of the cv is incremented twice;  The CX one is
301  * decremented by LEAVESUB, the other by LEAVE. */
302
303 #define PUSHSUB_BASE(cx)                                                \
304         ENTRY_PROBE(GvENAME(CvGV(cv)),                                  \
305                 CopFILE((const COP *)CvSTART(cv)),                      \
306                 CopLINE((const COP *)CvSTART(cv)));                     \
307                                                                         \
308         cx->blk_sub.cv = cv;                                            \
309         cx->blk_sub.olddepth = CvDEPTH(cv);                             \
310         cx->cx_type |= (hasargs) ? CXp_HASARGS : 0;                     \
311         cx->blk_sub.retop = NULL;                                       \
312         if (!CvDEPTH(cv)) {                                             \
313             SvREFCNT_inc_simple_void_NN(cv);                            \
314             SvREFCNT_inc_simple_void_NN(cv);                            \
315             SAVEFREESV(cv);                                             \
316         }
317
318
319 #define PUSHSUB(cx)                                                     \
320         PUSHSUB_BASE(cx)                                                \
321         cx->blk_u16 = PL_op->op_private &                               \
322                               (OPpLVAL_INTRO|OPpENTERSUB_INARGS);
323
324 /* variant for use by OP_DBSTATE, where op_private holds hint bits */
325 #define PUSHSUB_DB(cx)                                                  \
326         PUSHSUB_BASE(cx)                                                \
327         cx->blk_u16 = 0;
328
329
330 #define PUSHFORMAT(cx, retop)                                           \
331         cx->blk_format.cv = cv;                                         \
332         cx->blk_format.gv = gv;                                         \
333         cx->blk_format.retop = (retop);                                 \
334         cx->blk_format.dfoutgv = PL_defoutgv;                           \
335         SvREFCNT_inc_void(cx->blk_format.dfoutgv)
336
337 #define POP_SAVEARRAY()                                         \
338     STMT_START {                                                        \
339         SvREFCNT_dec(GvAV(PL_defgv));                                   \
340         GvAV(PL_defgv) = cx->blk_sub.savearray;                         \
341     } STMT_END
342
343 /* junk in @_ spells trouble when cloning CVs and in pp_caller(), so don't
344  * leave any (a fast av_clear(ary), basically) */
345 #define CLEAR_ARGARRAY(ary) \
346     STMT_START {                                                        \
347         AvMAX(ary) += AvARRAY(ary) - AvALLOC(ary);                      \
348         AvARRAY(ary) = AvALLOC(ary);                                    \
349         AvFILLp(ary) = -1;                                              \
350     } STMT_END
351
352 #define POPSUB(cx,sv)                                                   \
353     STMT_START {                                                        \
354         RETURN_PROBE(GvENAME(CvGV((const CV*)cx->blk_sub.cv)),          \
355                 CopFILE((COP*)CvSTART((const CV*)cx->blk_sub.cv)),      \
356                 CopLINE((COP*)CvSTART((const CV*)cx->blk_sub.cv)));     \
357                                                                         \
358         if (CxHASARGS(cx)) {                                            \
359             POP_SAVEARRAY();                                            \
360             /* abandon @_ if it got reified */                          \
361             if (AvREAL(cx->blk_sub.argarray)) {                         \
362                 const SSize_t fill = AvFILLp(cx->blk_sub.argarray);     \
363                 SvREFCNT_dec(cx->blk_sub.argarray);                     \
364                 cx->blk_sub.argarray = newAV();                         \
365                 av_extend(cx->blk_sub.argarray, fill);                  \
366                 AvREIFY_only(cx->blk_sub.argarray);                     \
367                 CX_CURPAD_SV(cx->blk_sub, 0) = MUTABLE_SV(cx->blk_sub.argarray); \
368             }                                                           \
369             else {                                                      \
370                 CLEAR_ARGARRAY(cx->blk_sub.argarray);                   \
371             }                                                           \
372         }                                                               \
373         sv = MUTABLE_SV(cx->blk_sub.cv);                                \
374         if (sv && (CvDEPTH((const CV*)sv) = cx->blk_sub.olddepth))      \
375             sv = NULL;                                          \
376     } STMT_END
377
378 #define LEAVESUB(sv)                                                    \
379     STMT_START {                                                        \
380         if (sv)                                                         \
381             SvREFCNT_dec(sv);                                           \
382     } STMT_END
383
384 #define POPFORMAT(cx)                                                   \
385         setdefout(cx->blk_format.dfoutgv);                              \
386         SvREFCNT_dec(cx->blk_format.dfoutgv);
387
388 /* eval context */
389 struct block_eval {
390     OP *        retop;  /* op to execute on exit from eval */
391     /* Above here is the same for sub, format and eval.  */
392     SV *        old_namesv;
393     OP *        old_eval_root;
394     SV *        cur_text;
395     CV *        cv;
396     JMPENV *    cur_top_env; /* value of PL_top_env when eval CX created */
397 };
398
399 /* If we ever need more than 512 op types, change the shift from 7.
400    blku_gimme is actually also only 2 bits, so could be merged with something.
401 */
402
403 #define CxOLD_IN_EVAL(cx)       (((cx)->blk_u16) & 0x7F)
404 #define CxOLD_OP_TYPE(cx)       (((cx)->blk_u16) >> 7)
405
406 #define PUSHEVAL(cx,n)                                                  \
407     STMT_START {                                                        \
408         assert(!(PL_in_eval & ~0x7F));                                  \
409         assert(!(PL_op->op_type & ~0x1FF));                             \
410         cx->blk_u16 = (PL_in_eval & 0x7F) | ((U16)PL_op->op_type << 7); \
411         cx->blk_eval.old_namesv = (n ? newSVpv(n,0) : NULL);            \
412         cx->blk_eval.old_eval_root = PL_eval_root;                      \
413         cx->blk_eval.cur_text = PL_parser ? PL_parser->linestr : NULL;  \
414         cx->blk_eval.cv = NULL; /* set by doeval(), as applicable */    \
415         cx->blk_eval.retop = NULL;                                      \
416         cx->blk_eval.cur_top_env = PL_top_env;                          \
417     } STMT_END
418
419 #define POPEVAL(cx)                                                     \
420     STMT_START {                                                        \
421         PL_in_eval = CxOLD_IN_EVAL(cx);                                 \
422         optype = CxOLD_OP_TYPE(cx);                                     \
423         PL_eval_root = cx->blk_eval.old_eval_root;                      \
424         if (cx->blk_eval.old_namesv)                                    \
425             sv_2mortal(cx->blk_eval.old_namesv);                        \
426     } STMT_END
427
428 /* loop context */
429 struct block_loop {
430     I32         resetsp;
431     LOOP *      my_op;  /* My op, that contains redo, next and last ops.  */
432     /* (except for non_ithreads we need to modify next_op in pp_ctl.c, hence
433         why next_op is conditionally defined below.)  */
434 #ifdef USE_ITHREADS
435     PAD         *oldcomppad; /* Also used for the GV, if targoffset is 0 */
436     /* This is also accesible via cx->blk_loop.my_op->op_targ */
437     PADOFFSET   targoffset;
438 #else
439     OP *        next_op;
440     SV **       itervar;
441 #endif
442     union {
443         struct { /* valid if type is LOOP_FOR or LOOP_PLAIN (but {NULL,0})*/
444             AV * ary; /* use the stack if this is NULL */
445             IV ix;
446         } ary;
447         struct { /* valid if type is LOOP_LAZYIV */
448             IV cur;
449             IV end;
450         } lazyiv;
451         struct { /* valid if type if LOOP_LAZYSV */
452             SV * cur;
453             SV * end; /* maxiumum value (or minimum in reverse) */
454         } lazysv;
455     } state_u;
456 };
457
458 #ifdef USE_ITHREADS
459 #  define CxITERVAR(c)                                                  \
460         ((c)->blk_loop.oldcomppad                                       \
461          ? (CxPADLOOP(c)                                                \
462             ? &CX_CURPAD_SV( (c)->blk_loop, (c)->blk_loop.targoffset )  \
463             : &GvSV((GV*)(c)->blk_loop.oldcomppad))                     \
464          : (SV**)NULL)
465 #  define CX_ITERDATA_SET(cx,idata,o)                                   \
466         if ((cx->blk_loop.targoffset = (o)))                            \
467             CX_CURPAD_SAVE(cx->blk_loop);                               \
468         else                                                            \
469             cx->blk_loop.oldcomppad = (idata);
470 #else
471 #  define CxITERVAR(c)          ((c)->blk_loop.itervar)
472 #  define CX_ITERDATA_SET(cx,ivar,o)                                    \
473         cx->blk_loop.itervar = (SV**)(ivar);
474 #endif
475 #define CxLABEL(c)      (0 + CopLABEL((c)->blk_oldcop))
476 #define CxHASARGS(c)    (((c)->cx_type & CXp_HASARGS) == CXp_HASARGS)
477 #define CxLVAL(c)       (0 + (c)->blk_u16)
478
479 #ifdef USE_ITHREADS
480 #  define PUSHLOOP_OP_NEXT              /* No need to do anything.  */
481 #  define CX_LOOP_NEXTOP_GET(cx)        ((cx)->blk_loop.my_op->op_nextop + 0)
482 #else
483 #  define PUSHLOOP_OP_NEXT              cx->blk_loop.next_op = cLOOP->op_nextop
484 #  define CX_LOOP_NEXTOP_GET(cx)        ((cx)->blk_loop.next_op + 0)
485 #endif
486
487 #define PUSHLOOP_PLAIN(cx, s)                                           \
488         cx->blk_loop.resetsp = s - PL_stack_base;                       \
489         cx->blk_loop.my_op = cLOOP;                                     \
490         PUSHLOOP_OP_NEXT;                                               \
491         cx->blk_loop.state_u.ary.ary = NULL;                            \
492         cx->blk_loop.state_u.ary.ix = 0;                                \
493         CX_ITERDATA_SET(cx, NULL, 0);
494
495 #define PUSHLOOP_FOR(cx, dat, s, offset)                                \
496         cx->blk_loop.resetsp = s - PL_stack_base;                       \
497         cx->blk_loop.my_op = cLOOP;                                     \
498         PUSHLOOP_OP_NEXT;                                               \
499         cx->blk_loop.state_u.ary.ary = NULL;                            \
500         cx->blk_loop.state_u.ary.ix = 0;                                \
501         CX_ITERDATA_SET(cx, dat, offset);
502
503 #define POPLOOP(cx)                                                     \
504         if (CxTYPE(cx) == CXt_LOOP_LAZYSV) {                            \
505             SvREFCNT_dec(cx->blk_loop.state_u.lazysv.cur);              \
506             SvREFCNT_dec(cx->blk_loop.state_u.lazysv.end);              \
507         }                                                               \
508         if (CxTYPE(cx) == CXt_LOOP_FOR)                                 \
509             SvREFCNT_dec(cx->blk_loop.state_u.ary.ary);
510
511 /* given/when context */
512 struct block_givwhen {
513         OP *leave_op;
514 };
515
516 #define PUSHGIVEN(cx)                                                   \
517         cx->blk_givwhen.leave_op = cLOGOP->op_other;
518
519 #define PUSHWHEN PUSHGIVEN
520
521 /* context common to subroutines, evals and loops */
522 struct block {
523     U8          blku_type;      /* what kind of context this is */
524     U8          blku_gimme;     /* is this block running in list context? */
525     U16         blku_u16;       /* used by block_sub and block_eval (so far) */
526     I32         blku_oldsp;     /* stack pointer to copy stuff down to */
527     COP *       blku_oldcop;    /* old curcop pointer */
528     I32         blku_oldmarksp; /* mark stack index */
529     I32         blku_oldscopesp;        /* scope stack index */
530     PMOP *      blku_oldpm;     /* values of pattern match vars */
531
532     union {
533         struct block_sub        blku_sub;
534         struct block_format     blku_format;
535         struct block_eval       blku_eval;
536         struct block_loop       blku_loop;
537         struct block_givwhen    blku_givwhen;
538     } blk_u;
539 };
540 #define blk_oldsp       cx_u.cx_blk.blku_oldsp
541 #define blk_oldcop      cx_u.cx_blk.blku_oldcop
542 #define blk_oldmarksp   cx_u.cx_blk.blku_oldmarksp
543 #define blk_oldscopesp  cx_u.cx_blk.blku_oldscopesp
544 #define blk_oldpm       cx_u.cx_blk.blku_oldpm
545 #define blk_gimme       cx_u.cx_blk.blku_gimme
546 #define blk_u16         cx_u.cx_blk.blku_u16
547 #define blk_sub         cx_u.cx_blk.blk_u.blku_sub
548 #define blk_format      cx_u.cx_blk.blk_u.blku_format
549 #define blk_eval        cx_u.cx_blk.blk_u.blku_eval
550 #define blk_loop        cx_u.cx_blk.blk_u.blku_loop
551 #define blk_givwhen     cx_u.cx_blk.blk_u.blku_givwhen
552
553 /* Enter a block. */
554 #define PUSHBLOCK(cx,t,sp) CXINC, cx = &cxstack[cxstack_ix],            \
555         cx->cx_type             = t,                                    \
556         cx->blk_oldsp           = sp - PL_stack_base,                   \
557         cx->blk_oldcop          = PL_curcop,                            \
558         cx->blk_oldmarksp       = PL_markstack_ptr - PL_markstack,      \
559         cx->blk_oldscopesp      = PL_scopestack_ix,                     \
560         cx->blk_oldpm           = PL_curpm,                             \
561         cx->blk_gimme           = (U8)gimme;                            \
562         DEBUG_l( PerlIO_printf(Perl_debug_log, "Entering block %ld, type %s\n", \
563                     (long)cxstack_ix, PL_block_type[CxTYPE(cx)]); )
564
565 /* Exit a block (RETURN and LAST). */
566 #define POPBLOCK(cx,pm) cx = &cxstack[cxstack_ix--],                    \
567         newsp            = PL_stack_base + cx->blk_oldsp,               \
568         PL_curcop        = cx->blk_oldcop,                              \
569         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
570         PL_scopestack_ix = cx->blk_oldscopesp,                          \
571         pm               = cx->blk_oldpm,                               \
572         gimme            = cx->blk_gimme;                               \
573         DEBUG_SCOPE("POPBLOCK");                                        \
574         DEBUG_l( PerlIO_printf(Perl_debug_log, "Leaving block %ld, type %s\n",          \
575                     (long)cxstack_ix+1,PL_block_type[CxTYPE(cx)]); )
576
577 /* Continue a block elsewhere (NEXT and REDO). */
578 #define TOPBLOCK(cx) cx  = &cxstack[cxstack_ix],                        \
579         PL_stack_sp      = PL_stack_base + cx->blk_oldsp,               \
580         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
581         PL_scopestack_ix = cx->blk_oldscopesp,                          \
582         PL_curpm         = cx->blk_oldpm;                               \
583         DEBUG_SCOPE("TOPBLOCK");
584
585 /* substitution context */
586 struct subst {
587     U8          sbu_type;       /* what kind of context this is */
588     U8          sbu_rflags;
589     U16         sbu_rxtainted;  /* matches struct block */
590     I32         sbu_iters;
591     I32         sbu_maxiters;
592     I32         sbu_oldsave;
593     char *      sbu_orig;
594     SV *        sbu_dstr;
595     SV *        sbu_targ;
596     char *      sbu_s;
597     char *      sbu_m;
598     char *      sbu_strend;
599     void *      sbu_rxres;
600     REGEXP *    sbu_rx;
601 };
602 #define sb_iters        cx_u.cx_subst.sbu_iters
603 #define sb_maxiters     cx_u.cx_subst.sbu_maxiters
604 #define sb_rflags       cx_u.cx_subst.sbu_rflags
605 #define sb_oldsave      cx_u.cx_subst.sbu_oldsave
606 #define sb_once         cx_u.cx_subst.sbu_once
607 #define sb_rxtainted    cx_u.cx_subst.sbu_rxtainted
608 #define sb_orig         cx_u.cx_subst.sbu_orig
609 #define sb_dstr         cx_u.cx_subst.sbu_dstr
610 #define sb_targ         cx_u.cx_subst.sbu_targ
611 #define sb_s            cx_u.cx_subst.sbu_s
612 #define sb_m            cx_u.cx_subst.sbu_m
613 #define sb_strend       cx_u.cx_subst.sbu_strend
614 #define sb_rxres        cx_u.cx_subst.sbu_rxres
615 #define sb_rx           cx_u.cx_subst.sbu_rx
616
617 #ifdef PERL_CORE
618 #  define PUSHSUBST(cx) CXINC, cx = &cxstack[cxstack_ix],               \
619         cx->sb_iters            = iters,                                \
620         cx->sb_maxiters         = maxiters,                             \
621         cx->sb_rflags           = r_flags,                              \
622         cx->sb_oldsave          = oldsave,                              \
623         cx->sb_rxtainted        = rxtainted,                            \
624         cx->sb_orig             = orig,                                 \
625         cx->sb_dstr             = dstr,                                 \
626         cx->sb_targ             = targ,                                 \
627         cx->sb_s                = s,                                    \
628         cx->sb_m                = m,                                    \
629         cx->sb_strend           = strend,                               \
630         cx->sb_rxres            = NULL,                                 \
631         cx->sb_rx               = rx,                                   \
632         cx->cx_type             = CXt_SUBST | (once ? CXp_ONCE : 0);    \
633         rxres_save(&cx->sb_rxres, rx);                                  \
634         (void)ReREFCNT_inc(rx)
635
636 #  define POPSUBST(cx) cx = &cxstack[cxstack_ix--];                     \
637         rxres_free(&cx->sb_rxres);                                      \
638         ReREFCNT_dec(cx->sb_rx)
639 #endif
640
641 #define CxONCE(cx)              ((cx)->cx_type & CXp_ONCE)
642
643 struct context {
644     union {
645         struct block    cx_blk;
646         struct subst    cx_subst;
647     } cx_u;
648 };
649 #define cx_type cx_u.cx_subst.sbu_type
650
651 /* If you re-order these, there is also an array of uppercase names in perl.h
652    and a static array of context names in pp_ctl.c  */
653 #define CXTYPEMASK      0xf
654 #define CXt_NULL        0
655 #define CXt_WHEN        1
656 #define CXt_BLOCK       2
657 /* When micro-optimising :-) keep GIVEN next to the LOOPs, as these 5 share a
658    jump table in pp_ctl.c
659    The first 4 don't have a 'case' in at least one switch statement in pp_ctl.c
660 */
661 #define CXt_GIVEN       3
662 /* This is first so that CXt_LOOP_FOR|CXt_LOOP_LAZYIV is CXt_LOOP_LAZYIV */
663 #define CXt_LOOP_FOR    4
664 #define CXt_LOOP_PLAIN  5
665 #define CXt_LOOP_LAZYSV 6
666 #define CXt_LOOP_LAZYIV 7
667 #define CXt_SUB         8
668 #define CXt_FORMAT      9
669 #define CXt_EVAL       10
670 #define CXt_SUBST      11
671 /* SUBST doesn't feature in all switch statements.  */
672
673 /* private flags for CXt_SUB and CXt_NULL
674    However, this is checked in many places which do not check the type, so
675    this bit needs to be kept clear for most everything else. For reasons I
676    haven't investigated, it can coexist with CXp_FOR_DEF */
677 #define CXp_MULTICALL   0x10    /* part of a multicall (so don't
678                                    tear down context on exit). */ 
679
680 /* private flags for CXt_SUB and CXt_FORMAT */
681 #define CXp_HASARGS     0x20
682
683 /* private flags for CXt_EVAL */
684 #define CXp_REAL        0x20    /* truly eval'', not a lookalike */
685 #define CXp_TRYBLOCK    0x40    /* eval{}, not eval'' or similar */
686
687 /* private flags for CXt_LOOP */
688 #define CXp_FOR_DEF     0x10    /* foreach using $_ */
689 #ifdef USE_ITHREADS
690 #  define CxPADLOOP(c)  ((c)->blk_loop.targoffset)
691 #endif
692
693 /* private flags for CXt_SUBST */
694 #define CXp_ONCE        0x10    /* What was sbu_once in struct subst */
695
696 #define CxTYPE(c)       ((c)->cx_type & CXTYPEMASK)
697 #define CxTYPE_is_LOOP(c)       (((c)->cx_type & 0xC) == 0x4)
698 #define CxMULTICALL(c)  (((c)->cx_type & CXp_MULTICALL)                 \
699                          == CXp_MULTICALL)
700 #define CxREALEVAL(c)   (((c)->cx_type & (CXTYPEMASK|CXp_REAL))         \
701                          == (CXt_EVAL|CXp_REAL))
702 #define CxTRYBLOCK(c)   (((c)->cx_type & (CXTYPEMASK|CXp_TRYBLOCK))     \
703                          == (CXt_EVAL|CXp_TRYBLOCK))
704 #define CxFOREACH(c)    (CxTYPE_is_LOOP(c) && CxTYPE(c) != CXt_LOOP_PLAIN)
705 #define CxFOREACHDEF(c) ((CxTYPE_is_LOOP(c) && CxTYPE(c) != CXt_LOOP_PLAIN) \
706                          && ((c)->cx_type & CXp_FOR_DEF))
707
708 #define CXINC (cxstack_ix < cxstack_max ? ++cxstack_ix : (cxstack_ix = cxinc()))
709
710 /* 
711 =head1 "Gimme" Values
712 */
713
714 /*
715 =for apidoc AmU||G_SCALAR
716 Used to indicate scalar context.  See C<GIMME_V>, C<GIMME>, and
717 L<perlcall>.
718
719 =for apidoc AmU||G_ARRAY
720 Used to indicate list context.  See C<GIMME_V>, C<GIMME> and
721 L<perlcall>.
722
723 =for apidoc AmU||G_VOID
724 Used to indicate void context.  See C<GIMME_V> and L<perlcall>.
725
726 =for apidoc AmU||G_DISCARD
727 Indicates that arguments returned from a callback should be discarded.  See
728 L<perlcall>.
729
730 =for apidoc AmU||G_EVAL
731
732 Used to force a Perl C<eval> wrapper around a callback.  See
733 L<perlcall>.
734
735 =for apidoc AmU||G_NOARGS
736
737 Indicates that no arguments are being sent to a callback.  See
738 L<perlcall>.
739
740 =cut
741 */
742
743 #define G_SCALAR        2
744 #define G_ARRAY         3
745 #define G_VOID          1
746 #define G_WANT          3
747
748 /* extra flags for Perl_call_* routines */
749 #define G_DISCARD       4       /* Call FREETMPS.
750                                    Don't change this without consulting the
751                                    hash actions codes defined in hv.h */
752 #define G_EVAL          8       /* Assume eval {} around subroutine call. */
753 #define G_NOARGS       16       /* Don't construct a @_ array. */
754 #define G_KEEPERR      32       /* Append errors to $@, don't overwrite it */
755 #define G_NODEBUG      64       /* Disable debugging at toplevel.  */
756 #define G_METHOD      128       /* Calling method. */
757 #define G_FAKINGEVAL  256       /* Faking an eval context for call_sv or
758                                    fold_constants. */
759
760 /* flag bits for PL_in_eval */
761 #define EVAL_NULL       0       /* not in an eval */
762 #define EVAL_INEVAL     1       /* some enclosing scope is an eval */
763 #define EVAL_WARNONLY   2       /* used by yywarn() when calling yyerror() */
764 #define EVAL_KEEPERR    4       /* set by Perl_call_sv if G_KEEPERR */
765 #define EVAL_INREQUIRE  8       /* The code is being required. */
766
767 /* Support for switching (stack and block) contexts.
768  * This ensures magic doesn't invalidate local stack and cx pointers.
769  */
770
771 #define PERLSI_UNKNOWN          -1
772 #define PERLSI_UNDEF            0
773 #define PERLSI_MAIN             1
774 #define PERLSI_MAGIC            2
775 #define PERLSI_SORT             3
776 #define PERLSI_SIGNAL           4
777 #define PERLSI_OVERLOAD         5
778 #define PERLSI_DESTROY          6
779 #define PERLSI_WARNHOOK         7
780 #define PERLSI_DIEHOOK          8
781 #define PERLSI_REQUIRE          9
782
783 struct stackinfo {
784     AV *                si_stack;       /* stack for current runlevel */
785     PERL_CONTEXT *      si_cxstack;     /* context stack for runlevel */
786     struct stackinfo *  si_prev;
787     struct stackinfo *  si_next;
788     I32                 si_cxix;        /* current context index */
789     I32                 si_cxmax;       /* maximum allocated index */
790     I32                 si_type;        /* type of runlevel */
791     I32                 si_markoff;     /* offset where markstack begins for us.
792                                          * currently used only with DEBUGGING,
793                                          * but not #ifdef-ed for bincompat */
794 };
795
796 typedef struct stackinfo PERL_SI;
797
798 #define cxstack         (PL_curstackinfo->si_cxstack)
799 #define cxstack_ix      (PL_curstackinfo->si_cxix)
800 #define cxstack_max     (PL_curstackinfo->si_cxmax)
801
802 #ifdef DEBUGGING
803 #  define       SET_MARK_OFFSET \
804     PL_curstackinfo->si_markoff = PL_markstack_ptr - PL_markstack
805 #else
806 #  define       SET_MARK_OFFSET NOOP
807 #endif
808
809 #define PUSHSTACKi(type) \
810     STMT_START {                                                        \
811         PERL_SI *next = PL_curstackinfo->si_next;                       \
812         if (!next) {                                                    \
813             next = new_stackinfo(32, 2048/sizeof(PERL_CONTEXT) - 1);    \
814             next->si_prev = PL_curstackinfo;                            \
815             PL_curstackinfo->si_next = next;                            \
816         }                                                               \
817         next->si_type = type;                                           \
818         next->si_cxix = -1;                                             \
819         AvFILLp(next->si_stack) = 0;                                    \
820         SWITCHSTACK(PL_curstack,next->si_stack);                        \
821         PL_curstackinfo = next;                                         \
822         SET_MARK_OFFSET;                                                \
823     } STMT_END
824
825 #define PUSHSTACK PUSHSTACKi(PERLSI_UNKNOWN)
826
827 /* POPSTACK works with PL_stack_sp, so it may need to be bracketed by
828  * PUTBACK/SPAGAIN to flush/refresh any local SP that may be active */
829 #define POPSTACK \
830     STMT_START {                                                        \
831         dSP;                                                            \
832         PERL_SI * const prev = PL_curstackinfo->si_prev;                \
833         if (!prev) {                                                    \
834             PerlIO_printf(Perl_error_log, "panic: POPSTACK\n");         \
835             my_exit(1);                                                 \
836         }                                                               \
837         SWITCHSTACK(PL_curstack,prev->si_stack);                        \
838         /* don't free prev here, free them all at the END{} */          \
839         PL_curstackinfo = prev;                                         \
840     } STMT_END
841
842 #define POPSTACK_TO(s) \
843     STMT_START {                                                        \
844         while (PL_curstack != s) {                                      \
845             dounwind(-1);                                               \
846             POPSTACK;                                                   \
847         }                                                               \
848     } STMT_END
849
850 #define IN_PERL_COMPILETIME     (PL_curcop == &PL_compiling)
851 #define IN_PERL_RUNTIME         (PL_curcop != &PL_compiling)
852
853 /*
854 =head1 Multicall Functions
855
856 =for apidoc Ams||dMULTICALL
857 Declare local variables for a multicall. See L<perlcall/Lightweight Callbacks>.
858
859 =for apidoc Ams||PUSH_MULTICALL
860 Opening bracket for a lightweight callback.
861 See L<perlcall/Lightweight Callbacks>.
862
863 =for apidoc Ams||MULTICALL
864 Make a lightweight callback. See L<perlcall/Lightweight Callbacks>.
865
866 =for apidoc Ams||POP_MULTICALL
867 Closing bracket for a lightweight callback.
868 See L<perlcall/Lightweight Callbacks>.
869
870 =cut
871 */
872
873 #define dMULTICALL \
874     SV **newsp;                 /* set by POPBLOCK */                   \
875     PERL_CONTEXT *cx;                                                   \
876     CV *multicall_cv;                                                   \
877     OP *multicall_cop;                                                  \
878     bool multicall_oldcatch;                                            \
879     U8 hasargs = 0              /* used by PUSHSUB */
880
881 #define PUSH_MULTICALL(the_cv) \
882     STMT_START {                                                        \
883         CV * const _nOnclAshIngNamE_ = the_cv;                          \
884         CV * const cv = _nOnclAshIngNamE_;                              \
885         AV * const padlist = CvPADLIST(cv);                             \
886         ENTER;                                                          \
887         multicall_oldcatch = CATCH_GET;                                 \
888         SAVETMPS; SAVEVPTR(PL_op);                                      \
889         CATCH_SET(TRUE);                                                \
890         PUSHSTACKi(PERLSI_SORT);                                        \
891         PUSHBLOCK(cx, CXt_SUB|CXp_MULTICALL, PL_stack_sp);              \
892         PUSHSUB(cx);                                                    \
893         if (++CvDEPTH(cv) >= 2) {                                       \
894             PERL_STACK_OVERFLOW_CHECK();                                \
895             Perl_pad_push(aTHX_ padlist, CvDEPTH(cv));                  \
896         }                                                               \
897         SAVECOMPPAD();                                                  \
898         PAD_SET_CUR_NOSAVE(padlist, CvDEPTH(cv));                       \
899         multicall_cv = cv;                                              \
900         multicall_cop = CvSTART(cv);                                    \
901     } STMT_END
902
903 #define MULTICALL \
904     STMT_START {                                                        \
905         PL_op = multicall_cop;                                          \
906         CALLRUNOPS(aTHX);                                               \
907     } STMT_END
908
909 #define POP_MULTICALL \
910     STMT_START {                                                        \
911         LEAVESUB(multicall_cv);                                         \
912         CvDEPTH(multicall_cv)--;                                        \
913         POPBLOCK(cx,PL_curpm);                                          \
914         POPSTACK;                                                       \
915         CATCH_SET(multicall_oldcatch);                                  \
916         LEAVE;                                                          \
917         SPAGAIN;                                                        \
918     } STMT_END
919
920 /*
921  * Local variables:
922  * c-indentation-style: bsd
923  * c-basic-offset: 4
924  * indent-tabs-mode: t
925  * End:
926  *
927  * ex: set ts=8 sts=4 sw=4 noet:
928  */