8a96331de33ced286214cc235aee5c0772e8bb7a
[perl.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 statement separators.
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 PL_start_env initialized when perl starts, and
18  * PL_top_env points to this initially, so PL_top_env should always be
19  * non-null.
20  *
21  * Existence of a non-null PL_top_env->je_prev implies it is valid to call
22  * longjmp() at that runlevel (we make sure PL_start_env.je_prev is always
23  * null to ensure this).
24  *
25  * je_mustcatch, when set at any runlevel to TRUE, means eval ops must
26  * establish a local jmpenv to handle exception traps.  Care must be taken
27  * to restore the previous value of je_mustcatch before exiting the
28  * stack frame iff JMPENV_PUSH was not called in that stack frame.
29  * GSAR 97-03-27
30  */
31
32 struct jmpenv {
33     struct jmpenv *     je_prev;
34     Sigjmp_buf          je_buf;         /* uninit if je_prev is NULL */
35     int                 je_ret;         /* last exception thrown */
36     bool                je_mustcatch;   /* need to call longjmp()? */
37 };
38
39 typedef struct jmpenv JMPENV;
40
41 /*
42  * How to build the first jmpenv.
43  *
44  * top_env needs to be non-zero. It points to an area
45  * in which longjmp() stuff is stored, as C callstack
46  * info there at least is thread specific this has to
47  * be per-thread. Otherwise a 'die' in a thread gives
48  * that thread the C stack of last thread to do an eval {}!
49  */
50
51 #define JMPENV_BOOTSTRAP \
52     STMT_START {                                \
53         PERL_POISON_EXPR(PoisonNew(&PL_start_env, 1, JMPENV));\
54         PL_top_env = &PL_start_env;             \
55         PL_start_env.je_prev = NULL;            \
56         PL_start_env.je_ret = -1;               \
57         PL_start_env.je_mustcatch = TRUE;       \
58     } STMT_END
59
60 /*
61  *   PERL_FLEXIBLE_EXCEPTIONS
62  * 
63  * All the flexible exceptions code has been removed.
64  * See the following threads for details:
65  *
66  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2004-07/msg00378.html
67  * 
68  * Joshua's original patches (which weren't applied) and discussion:
69  * 
70  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01396.html
71  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01489.html
72  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01491.html
73  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01608.html
74  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg02144.html
75  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg02998.html
76  * 
77  * Chip's reworked patch and discussion:
78  * 
79  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1999-03/msg00520.html
80  * 
81  * The flaw in these patches (which went unnoticed at the time) was
82  * that they moved some code that could potentially die() out of the
83  * region protected by the setjmp()s.  This caused exceptions within
84  * END blocks and such to not be handled by the correct setjmp().
85  * 
86  * The original patches that introduces flexible exceptions were:
87  *
88  * http://perl5.git.perl.org/perl.git/commit/312caa8e97f1c7ee342a9895c2f0e749625b4929
89  * http://perl5.git.perl.org/perl.git/commit/14dd3ad8c9bf82cf09798a22cc89a9862dfd6d1a                                        
90  *  
91  */
92
93 #define dJMPENV         JMPENV cur_env
94
95 #define JMPENV_PUSH(v) \
96     STMT_START {                                                        \
97         DEBUG_l({                                                       \
98             int i = 0; JMPENV *p = PL_top_env;                          \
99             while (p) { i++; p = p->je_prev; }                          \
100             Perl_deb(aTHX_ "JUMPENV_PUSH level=%d at %s:%d\n",          \
101                          i,  __FILE__, __LINE__);})                     \
102         cur_env.je_prev = PL_top_env;                                   \
103         cur_env.je_ret = PerlProc_setjmp(cur_env.je_buf, SCOPE_SAVES_SIGNAL_MASK);              \
104         PL_top_env = &cur_env;                                          \
105         cur_env.je_mustcatch = FALSE;                                   \
106         (v) = cur_env.je_ret;                                           \
107     } STMT_END
108
109 #define JMPENV_POP \
110     STMT_START {                                                        \
111         DEBUG_l({                                                       \
112             int i = -1; JMPENV *p = PL_top_env;                         \
113             while (p) { i++; p = p->je_prev; }                          \
114             Perl_deb(aTHX_ "JUMPENV_POP level=%d at %s:%d\n",           \
115                          i, __FILE__, __LINE__);})                      \
116         assert(PL_top_env == &cur_env);                                 \
117         PL_top_env = cur_env.je_prev;                                   \
118     } STMT_END
119
120 #define JMPENV_JUMP(v) \
121     STMT_START {                                                \
122         DEBUG_l({                                               \
123             int i = -1; JMPENV *p = PL_top_env;                 \
124             while (p) { i++; p = p->je_prev; }                  \
125             Perl_deb(aTHX_ "JUMPENV_JUMP(%d) level=%d at %s:%d\n", \
126                          (int)v, i, __FILE__, __LINE__);})      \
127         if (PL_top_env->je_prev)                                \
128             PerlProc_longjmp(PL_top_env->je_buf, (v));          \
129         if ((v) == 2)                                           \
130             PerlProc_exit(STATUS_EXIT);                         \
131         PerlIO_printf(PerlIO_stderr(), "panic: top_env, v=%d\n", (int)v); \
132         PerlProc_exit(1);                                       \
133     } STMT_END
134
135 #define CATCH_GET               (PL_top_env->je_mustcatch)
136 #define CATCH_SET(v) \
137     STMT_START {                                                        \
138         DEBUG_l(                                                        \
139             Perl_deb(aTHX_                                              \
140                 "JUMPLEVEL set catch %d => %d (for %p) at %s:%d\n",     \
141                  PL_top_env->je_mustcatch, v, (void*)PL_top_env,        \
142                  __FILE__, __LINE__);)                                  \
143         PL_top_env->je_mustcatch = (v);                                 \
144     } STMT_END
145
146 /*
147 =head1 COP Hint Hashes
148 */
149
150 typedef struct refcounted_he COPHH;
151
152 #define COPHH_KEY_UTF8 REFCOUNTED_HE_KEY_UTF8
153
154 /*
155 =for apidoc Amx|SV *|cophh_fetch_pvn|const COPHH *cophh|const char *keypv|STRLEN keylen|U32 hash|U32 flags
156
157 Look up the entry in the cop hints hash I<cophh> with the key specified by
158 I<keypv> and I<keylen>.  If I<flags> has the C<COPHH_KEY_UTF8> bit set,
159 the key octets are interpreted as UTF-8, otherwise they are interpreted
160 as Latin-1.  I<hash> is a precomputed hash of the key string, or zero if
161 it has not been precomputed.  Returns a mortal scalar copy of the value
162 associated with the key, or C<&PL_sv_placeholder> if there is no value
163 associated with the key.
164
165 =cut
166 */
167
168 #define cophh_fetch_pvn(cophh, keypv, keylen, hash, flags) \
169     Perl_refcounted_he_fetch_pvn(aTHX_ cophh, keypv, keylen, hash, flags)
170
171 /*
172 =for apidoc Amx|SV *|cophh_fetch_pvs|const COPHH *cophh|const char *key|U32 flags
173
174 Like L</cophh_fetch_pvn>, but takes a literal string instead of a
175 string/length pair, and no precomputed hash.
176
177 =cut
178 */
179
180 #define cophh_fetch_pvs(cophh, key, flags) \
181     Perl_refcounted_he_fetch_pvn(aTHX_ cophh, STR_WITH_LEN(key), 0, flags)
182
183 /*
184 =for apidoc Amx|SV *|cophh_fetch_pv|const COPHH *cophh|const char *key|U32 hash|U32 flags
185
186 Like L</cophh_fetch_pvn>, but takes a nul-terminated string instead of
187 a string/length pair.
188
189 =cut
190 */
191
192 #define cophh_fetch_pv(cophh, key, hash, flags) \
193     Perl_refcounted_he_fetch_pv(aTHX_ cophh, key, hash, flags)
194
195 /*
196 =for apidoc Amx|SV *|cophh_fetch_sv|const COPHH *cophh|SV *key|U32 hash|U32 flags
197
198 Like L</cophh_fetch_pvn>, but takes a Perl scalar instead of a
199 string/length pair.
200
201 =cut
202 */
203
204 #define cophh_fetch_sv(cophh, key, hash, flags) \
205     Perl_refcounted_he_fetch_sv(aTHX_ cophh, key, hash, flags)
206
207 /*
208 =for apidoc Amx|HV *|cophh_2hv|const COPHH *cophh|U32 flags
209
210 Generates and returns a standard Perl hash representing the full set of
211 key/value pairs in the cop hints hash I<cophh>.  I<flags> is currently
212 unused and must be zero.
213
214 =cut
215 */
216
217 #define cophh_2hv(cophh, flags) \
218     Perl_refcounted_he_chain_2hv(aTHX_ cophh, flags)
219
220 /*
221 =for apidoc Amx|COPHH *|cophh_copy|COPHH *cophh
222
223 Make and return a complete copy of the cop hints hash I<cophh>.
224
225 =cut
226 */
227
228 #define cophh_copy(cophh) Perl_refcounted_he_inc(aTHX_ cophh)
229
230 /*
231 =for apidoc Amx|void|cophh_free|COPHH *cophh
232
233 Discard the cop hints hash I<cophh>, freeing all resources associated
234 with it.
235
236 =cut
237 */
238
239 #define cophh_free(cophh) Perl_refcounted_he_free(aTHX_ cophh)
240
241 /*
242 =for apidoc Amx|COPHH *|cophh_new_empty
243
244 Generate and return a fresh cop hints hash containing no entries.
245
246 =cut
247 */
248
249 #define cophh_new_empty() ((COPHH *)NULL)
250
251 /*
252 =for apidoc Amx|COPHH *|cophh_store_pvn|COPHH *cophh|const char *keypv|STRLEN keylen|U32 hash|SV *value|U32 flags
253
254 Stores a value, associated with a key, in the cop hints hash I<cophh>,
255 and returns the modified hash.  The returned hash pointer is in general
256 not the same as the hash pointer that was passed in.  The input hash is
257 consumed by the function, and the pointer to it must not be subsequently
258 used.  Use L</cophh_copy> if you need both hashes.
259
260 The key is specified by I<keypv> and I<keylen>.  If I<flags> has the
261 C<COPHH_KEY_UTF8> bit set, the key octets are interpreted as UTF-8,
262 otherwise they are interpreted as Latin-1.  I<hash> is a precomputed
263 hash of the key string, or zero if it has not been precomputed.
264
265 I<value> is the scalar value to store for this key.  I<value> is copied
266 by this function, which thus does not take ownership of any reference
267 to it, and later changes to the scalar will not be reflected in the
268 value visible in the cop hints hash.  Complex types of scalar will not
269 be stored with referential integrity, but will be coerced to strings.
270
271 =cut
272 */
273
274 #define cophh_store_pvn(cophh, keypv, keylen, hash, value, flags) \
275     Perl_refcounted_he_new_pvn(aTHX_ cophh, keypv, keylen, hash, value, flags)
276
277 /*
278 =for apidoc Amx|COPHH *|cophh_store_pvs|const COPHH *cophh|const char *key|SV *value|U32 flags
279
280 Like L</cophh_store_pvn>, but takes a literal string instead of a
281 string/length pair, and no precomputed hash.
282
283 =cut
284 */
285
286 #define cophh_store_pvs(cophh, key, value, flags) \
287     Perl_refcounted_he_new_pvn(aTHX_ cophh, STR_WITH_LEN(key), 0, value, flags)
288
289 /*
290 =for apidoc Amx|COPHH *|cophh_store_pv|const COPHH *cophh|const char *key|U32 hash|SV *value|U32 flags
291
292 Like L</cophh_store_pvn>, but takes a nul-terminated string instead of
293 a string/length pair.
294
295 =cut
296 */
297
298 #define cophh_store_pv(cophh, key, hash, value, flags) \
299     Perl_refcounted_he_new_pv(aTHX_ cophh, key, hash, value, flags)
300
301 /*
302 =for apidoc Amx|COPHH *|cophh_store_sv|const COPHH *cophh|SV *key|U32 hash|SV *value|U32 flags
303
304 Like L</cophh_store_pvn>, but takes a Perl scalar instead of a
305 string/length pair.
306
307 =cut
308 */
309
310 #define cophh_store_sv(cophh, key, hash, value, flags) \
311     Perl_refcounted_he_new_sv(aTHX_ cophh, key, hash, value, flags)
312
313 /*
314 =for apidoc Amx|COPHH *|cophh_delete_pvn|COPHH *cophh|const char *keypv|STRLEN keylen|U32 hash|U32 flags
315
316 Delete a key and its associated value from the cop hints hash I<cophh>,
317 and returns the modified hash.  The returned hash pointer is in general
318 not the same as the hash pointer that was passed in.  The input hash is
319 consumed by the function, and the pointer to it must not be subsequently
320 used.  Use L</cophh_copy> if you need both hashes.
321
322 The key is specified by I<keypv> and I<keylen>.  If I<flags> has the
323 C<COPHH_KEY_UTF8> bit set, the key octets are interpreted as UTF-8,
324 otherwise they are interpreted as Latin-1.  I<hash> is a precomputed
325 hash of the key string, or zero if it has not been precomputed.
326
327 =cut
328 */
329
330 #define cophh_delete_pvn(cophh, keypv, keylen, hash, flags) \
331     Perl_refcounted_he_new_pvn(aTHX_ cophh, keypv, keylen, hash, \
332         (SV *)NULL, flags)
333
334 /*
335 =for apidoc Amx|COPHH *|cophh_delete_pvs|const COPHH *cophh|const char *key|U32 flags
336
337 Like L</cophh_delete_pvn>, but takes a literal string instead of a
338 string/length pair, and no precomputed hash.
339
340 =cut
341 */
342
343 #define cophh_delete_pvs(cophh, key, flags) \
344     Perl_refcounted_he_new_pvn(aTHX_ cophh, STR_WITH_LEN(key), 0, \
345         (SV *)NULL, flags)
346
347 /*
348 =for apidoc Amx|COPHH *|cophh_delete_pv|const COPHH *cophh|const char *key|U32 hash|U32 flags
349
350 Like L</cophh_delete_pvn>, but takes a nul-terminated string instead of
351 a string/length pair.
352
353 =cut
354 */
355
356 #define cophh_delete_pv(cophh, key, hash, flags) \
357     Perl_refcounted_he_new_pv(aTHX_ cophh, key, hash, (SV *)NULL, flags)
358
359 /*
360 =for apidoc Amx|COPHH *|cophh_delete_sv|const COPHH *cophh|SV *key|U32 hash|U32 flags
361
362 Like L</cophh_delete_pvn>, but takes a Perl scalar instead of a
363 string/length pair.
364
365 =cut
366 */
367
368 #define cophh_delete_sv(cophh, key, hash, flags) \
369     Perl_refcounted_he_new_sv(aTHX_ cophh, key, hash, (SV *)NULL, flags)
370
371 #include "mydtrace.h"
372
373 struct cop {
374     BASEOP
375     /* On LP64 putting this here takes advantage of the fact that BASEOP isn't
376        an exact multiple of 8 bytes to save structure padding.  */
377     line_t      cop_line;       /* line # of this command */
378     /* label for this construct is now stored in cop_hints_hash */
379 #ifdef USE_ITHREADS
380     PADOFFSET   cop_stashoff;   /* offset into PL_stashpad, for the
381                                    package the line was compiled in */
382     char *      cop_file;       /* file name the following line # is from */
383 #else
384     HV *        cop_stash;      /* package line was compiled in */
385     GV *        cop_filegv;     /* file the following line # is from */
386 #endif
387     U32         cop_hints;      /* hints bits from pragmata */
388     U32         cop_seq;        /* parse sequence number */
389     /* Beware. mg.c and warnings.pl assume the type of this is STRLEN *:  */
390     STRLEN *    cop_warnings;   /* lexical warnings bitmask */
391     /* compile time state of %^H.  See the comment in op.c for how this is
392        used to recreate a hash to return from caller.  */
393     COPHH *     cop_hints_hash;
394 };
395
396 #ifdef USE_ITHREADS
397 #  define CopFILE(c)            ((c)->cop_file)
398 #  define CopFILEGV(c)          (CopFILE(c) \
399                                  ? gv_fetchfile(CopFILE(c)) : NULL)
400                                  
401 #  ifdef NETWARE
402 #    define CopFILE_set(c,pv)   ((c)->cop_file = savepv(pv))
403 #    define CopFILE_setn(c,pv,l)  ((c)->cop_file = savepvn((pv),(l)))
404 #  else
405 #    define CopFILE_set(c,pv)   ((c)->cop_file = savesharedpv(pv))
406 #    define CopFILE_setn(c,pv,l)  ((c)->cop_file = savesharedpvn((pv),(l)))
407 #  endif
408
409 #  define CopFILESV(c)          (CopFILE(c) \
410                                  ? GvSV(gv_fetchfile(CopFILE(c))) : NULL)
411 #  define CopFILEAV(c)          (CopFILE(c) \
412                                  ? GvAV(gv_fetchfile(CopFILE(c))) : NULL)
413 #  define CopFILEAVx(c)         (assert_(CopFILE(c)) \
414                                    GvAV(gv_fetchfile(CopFILE(c))))
415
416 #  define CopSTASH(c)           PL_stashpad[(c)->cop_stashoff]
417 #  define CopSTASH_set(c,hv)    ((c)->cop_stashoff = (hv)               \
418                                     ? alloccopstash(hv)                 \
419                                     : 0)
420 #  ifdef NETWARE
421 #    define CopFILE_free(c) SAVECOPFILE_FREE(c)
422 #  else
423 #    define CopFILE_free(c)     (PerlMemShared_free(CopFILE(c)),(CopFILE(c) = NULL))
424 #  endif
425 #else
426 #  define CopFILEGV(c)          ((c)->cop_filegv)
427 #  define CopFILEGV_set(c,gv)   ((c)->cop_filegv = (GV*)SvREFCNT_inc(gv))
428 #  define CopFILE_set(c,pv)     CopFILEGV_set((c), gv_fetchfile(pv))
429 #  define CopFILE_setn(c,pv,l)  CopFILEGV_set((c), gv_fetchfile_flags((pv),(l),0))
430 #  define CopFILESV(c)          (CopFILEGV(c) ? GvSV(CopFILEGV(c)) : NULL)
431 #  define CopFILEAV(c)          (CopFILEGV(c) ? GvAV(CopFILEGV(c)) : NULL)
432 #  ifdef DEBUGGING
433 #    define CopFILEAVx(c)       (assert(CopFILEGV(c)), GvAV(CopFILEGV(c)))
434 #  else
435 #    define CopFILEAVx(c)       (GvAV(CopFILEGV(c)))
436 # endif
437 #  define CopFILE(c)            (CopFILEGV(c) \
438                                     ? GvNAME(CopFILEGV(c))+2 : NULL)
439 #  define CopSTASH(c)           ((c)->cop_stash)
440 #  define CopSTASH_set(c,hv)    ((c)->cop_stash = (hv))
441 #  define CopFILE_free(c)       (SvREFCNT_dec(CopFILEGV(c)),(CopFILEGV(c) = NULL))
442
443 #endif /* USE_ITHREADS */
444
445 #define CopSTASHPV(c)           (CopSTASH(c) ? HvNAME_get(CopSTASH(c)) : NULL)
446    /* cop_stash is not refcounted */
447 #define CopSTASHPV_set(c,pv)    CopSTASH_set((c), gv_stashpv(pv,GV_ADD))
448 #define CopSTASH_eq(c,hv)       (CopSTASH(c) == (hv))
449
450 #define CopHINTHASH_get(c)      ((COPHH*)((c)->cop_hints_hash))
451 #define CopHINTHASH_set(c,h)    ((c)->cop_hints_hash = (h))
452
453 /*
454 =head1 COP Hint Reading
455 */
456
457 /*
458 =for apidoc Am|SV *|cop_hints_fetch_pvn|const COP *cop|const char *keypv|STRLEN keylen|U32 hash|U32 flags
459
460 Look up the hint entry in the cop I<cop> with the key specified by
461 I<keypv> and I<keylen>.  If I<flags> has the C<COPHH_KEY_UTF8> bit set,
462 the key octets are interpreted as UTF-8, otherwise they are interpreted
463 as Latin-1.  I<hash> is a precomputed hash of the key string, or zero if
464 it has not been precomputed.  Returns a mortal scalar copy of the value
465 associated with the key, or C<&PL_sv_placeholder> if there is no value
466 associated with the key.
467
468 =cut
469 */
470
471 #define cop_hints_fetch_pvn(cop, keypv, keylen, hash, flags) \
472     cophh_fetch_pvn(CopHINTHASH_get(cop), keypv, keylen, hash, flags)
473
474 /*
475 =for apidoc Am|SV *|cop_hints_fetch_pvs|const COP *cop|const char *key|U32 flags
476
477 Like L</cop_hints_fetch_pvn>, but takes a literal string instead of a
478 string/length pair, and no precomputed hash.
479
480 =cut
481 */
482
483 #define cop_hints_fetch_pvs(cop, key, flags) \
484     cophh_fetch_pvs(CopHINTHASH_get(cop), key, flags)
485
486 /*
487 =for apidoc Am|SV *|cop_hints_fetch_pv|const COP *cop|const char *key|U32 hash|U32 flags
488
489 Like L</cop_hints_fetch_pvn>, but takes a nul-terminated string instead
490 of a string/length pair.
491
492 =cut
493 */
494
495 #define cop_hints_fetch_pv(cop, key, hash, flags) \
496     cophh_fetch_pv(CopHINTHASH_get(cop), key, hash, flags)
497
498 /*
499 =for apidoc Am|SV *|cop_hints_fetch_sv|const COP *cop|SV *key|U32 hash|U32 flags
500
501 Like L</cop_hints_fetch_pvn>, but takes a Perl scalar instead of a
502 string/length pair.
503
504 =cut
505 */
506
507 #define cop_hints_fetch_sv(cop, key, hash, flags) \
508     cophh_fetch_sv(CopHINTHASH_get(cop), key, hash, flags)
509
510 /*
511 =for apidoc Am|HV *|cop_hints_2hv|const COP *cop|U32 flags
512
513 Generates and returns a standard Perl hash representing the full set of
514 hint entries in the cop I<cop>.  I<flags> is currently unused and must
515 be zero.
516
517 =cut
518 */
519
520 #define cop_hints_2hv(cop, flags) \
521     cophh_2hv(CopHINTHASH_get(cop), flags)
522
523 #define CopLABEL(c)  Perl_cop_fetch_label(aTHX_ (c), NULL, NULL)
524 #define CopLABEL_len(c,len)  Perl_cop_fetch_label(aTHX_ (c), len, NULL)
525 #define CopLABEL_len_flags(c,len,flags)  Perl_cop_fetch_label(aTHX_ (c), len, flags)
526 #define CopLABEL_alloc(pv)      ((pv)?savepv(pv):NULL)
527
528 #define CopSTASH_ne(c,hv)       (!CopSTASH_eq(c,hv))
529 #define CopLINE(c)              ((c)->cop_line)
530 #define CopLINE_inc(c)          (++CopLINE(c))
531 #define CopLINE_dec(c)          (--CopLINE(c))
532 #define CopLINE_set(c,l)        (CopLINE(c) = (l))
533
534 /* OutCopFILE() is CopFILE for output (caller, die, warn, etc.) */
535 #define OutCopFILE(c) CopFILE(c)
536
537 #define CopHINTS_get(c)         ((c)->cop_hints + 0)
538 #define CopHINTS_set(c, h)      STMT_START {                            \
539                                     (c)->cop_hints = (h);               \
540                                 } STMT_END
541
542 /*
543  * Here we have some enormously heavy (or at least ponderous) wizardry.
544  */
545
546 /* subroutine context */
547 struct block_sub {
548     OP *        retop;  /* op to execute on exit from sub */
549     /* Above here is the same for sub, format and eval.  */
550     CV *        cv;
551     /* Above here is the same for sub and format.  */
552     AV *        savearray;
553     AV *        argarray;
554     I32         olddepth;
555     PAD         *oldcomppad;
556 };
557
558
559 /* format context */
560 struct block_format {
561     OP *        retop;  /* op to execute on exit from sub */
562     /* Above here is the same for sub, format and eval.  */
563     CV *        cv;
564     /* Above here is the same for sub and format.  */
565     GV *        gv;
566     GV *        dfoutgv;
567 };
568
569 /* base for the next two macros. Don't use directly.
570  * Note that the refcnt of the cv is incremented twice;  The CX one is
571  * decremented by LEAVESUB, the other by LEAVE. */
572
573 #define PUSHSUB_BASE(cx)                                                \
574         ENTRY_PROBE(CvNAMED(cv)                                         \
575                         ? HEK_KEY(CvNAME_HEK(cv))                       \
576                         : GvENAME(CvGV(cv)),                            \
577                 CopFILE((const COP *)CvSTART(cv)),                      \
578                 CopLINE((const COP *)CvSTART(cv)),                      \
579                 CopSTASHPV((const COP *)CvSTART(cv)));                  \
580                                                                         \
581         cx->blk_sub.cv = cv;                                            \
582         cx->blk_sub.olddepth = CvDEPTH(cv);                             \
583         cx->cx_type |= (hasargs) ? CXp_HASARGS : 0;                     \
584         cx->blk_sub.retop = NULL;                                       \
585         if (!CvDEPTH(cv)) {                                             \
586             SvREFCNT_inc_simple_void_NN(cv);                            \
587             SvREFCNT_inc_simple_void_NN(cv);                            \
588             SAVEFREESV(cv);                                             \
589         }
590
591 #define PUSHSUB_GET_LVALUE_MASK(func) \
592         /* If the context is indeterminate, then only the lvalue */     \
593         /* flags that the caller also has are applicable.        */     \
594         (                                                               \
595            (PL_op->op_flags & OPf_WANT)                                 \
596                ? OPpENTERSUB_LVAL_MASK                                  \
597                : !(PL_op->op_private & OPpENTERSUB_LVAL_MASK)           \
598                    ? 0 : (U8)func(aTHX)                                 \
599         )
600
601 #define PUSHSUB(cx)                                                     \
602     {                                                                   \
603         U8 phlags = PUSHSUB_GET_LVALUE_MASK(Perl_was_lvalue_sub);       \
604         PUSHSUB_BASE(cx)                                                \
605         cx->blk_u16 = PL_op->op_private &                               \
606                           (phlags|OPpDEREF);                            \
607     }
608
609 /* variant for use by OP_DBSTATE, where op_private holds hint bits */
610 #define PUSHSUB_DB(cx)                                                  \
611         PUSHSUB_BASE(cx)                                                \
612         cx->blk_u16 = 0;
613
614
615 #define PUSHFORMAT(cx, retop)                                           \
616         cx->blk_format.cv = cv;                                         \
617         cx->blk_format.gv = gv;                                         \
618         cx->blk_format.retop = (retop);                                 \
619         cx->blk_format.dfoutgv = PL_defoutgv;                           \
620         cx->blk_u16 = 0;                                                \
621         if (!CvDEPTH(cv)) SvREFCNT_inc_simple_void_NN(cv);              \
622         CvDEPTH(cv)++;                                                  \
623         SvREFCNT_inc_void(cx->blk_format.dfoutgv)
624
625 #define POP_SAVEARRAY()                                         \
626     STMT_START {                                                        \
627         SvREFCNT_dec(GvAV(PL_defgv));                                   \
628         GvAV(PL_defgv) = cx->blk_sub.savearray;                         \
629     } STMT_END
630
631 /* junk in @_ spells trouble when cloning CVs and in pp_caller(), so don't
632  * leave any (a fast av_clear(ary), basically) */
633 #define CLEAR_ARGARRAY(ary) \
634     STMT_START {                                                        \
635         AvMAX(ary) += AvARRAY(ary) - AvALLOC(ary);                      \
636         AvARRAY(ary) = AvALLOC(ary);                                    \
637         AvFILLp(ary) = -1;                                              \
638     } STMT_END
639
640 #define POPSUB(cx,sv)                                                   \
641     STMT_START {                                                        \
642         const I32 olddepth = cx->blk_sub.olddepth;                      \
643         if (!(cx->blk_u16 & CxPOPSUB_DONE)) {                           \
644         cx->blk_u16 |= CxPOPSUB_DONE;                                   \
645         RETURN_PROBE(CvNAMED(cx->blk_sub.cv)                            \
646                         ? HEK_KEY(CvNAME_HEK(cx->blk_sub.cv))           \
647                         : GvENAME(CvGV(cx->blk_sub.cv)),                \
648                 CopFILE((COP*)CvSTART((const CV*)cx->blk_sub.cv)),      \
649                 CopLINE((COP*)CvSTART((const CV*)cx->blk_sub.cv)),      \
650                 CopSTASHPV((COP*)CvSTART((const CV*)cx->blk_sub.cv)));  \
651                                                                         \
652         if (CxHASARGS(cx)) {                                            \
653             POP_SAVEARRAY();                                            \
654             /* abandon @_ if it got reified */                          \
655             if (AvREAL(cx->blk_sub.argarray)) {                         \
656                 const SSize_t fill = AvFILLp(cx->blk_sub.argarray);     \
657                 SvREFCNT_dec_NN(cx->blk_sub.argarray);                  \
658                 cx->blk_sub.argarray = newAV();                         \
659                 av_extend(cx->blk_sub.argarray, fill);                  \
660                 AvREIFY_only(cx->blk_sub.argarray);                     \
661                 CX_CURPAD_SV(cx->blk_sub, 0) = MUTABLE_SV(cx->blk_sub.argarray); \
662             }                                                           \
663             else {                                                      \
664                 CLEAR_ARGARRAY(cx->blk_sub.argarray);                   \
665             }                                                           \
666         }                                                               \
667         }                                                               \
668         sv = MUTABLE_SV(cx->blk_sub.cv);                                \
669         LEAVE_SCOPE(PL_scopestack[cx->blk_oldscopesp-1]);               \
670         if (sv && (CvDEPTH((const CV*)sv) = olddepth))                  \
671             sv = NULL;                                          \
672     } STMT_END
673
674 #define LEAVESUB(sv)                                                    \
675     STMT_START {                                                        \
676         SvREFCNT_dec(sv);                                               \
677     } STMT_END
678
679 #define POPFORMAT(cx)                                                   \
680     STMT_START {                                                        \
681         if (!(cx->blk_u16 & CxPOPSUB_DONE)) {                           \
682         CV * const cv = cx->blk_format.cv;                              \
683         GV * const dfuot = cx->blk_format.dfoutgv;                      \
684         cx->blk_u16 |= CxPOPSUB_DONE;                                   \
685         setdefout(dfuot);                                               \
686         LEAVE_SCOPE(PL_scopestack[cx->blk_oldscopesp-1]);               \
687         if (!--CvDEPTH(cv))                                             \
688             SvREFCNT_dec_NN(cx->blk_format.cv);                         \
689         SvREFCNT_dec_NN(dfuot);                                         \
690         }                                                               \
691     } STMT_END
692
693 /* eval context */
694 struct block_eval {
695     OP *        retop;  /* op to execute on exit from eval */
696     /* Above here is the same for sub, format and eval.  */
697     SV *        old_namesv;
698     OP *        old_eval_root;
699     SV *        cur_text;
700     CV *        cv;
701     JMPENV *    cur_top_env; /* value of PL_top_env when eval CX created */
702 };
703
704 /* If we ever need more than 512 op types, change the shift from 7.
705    blku_gimme is actually also only 2 bits, so could be merged with something.
706 */
707
708 #define CxOLD_IN_EVAL(cx)       (((cx)->blk_u16) & 0x7F)
709 #define CxOLD_OP_TYPE(cx)       (((cx)->blk_u16) >> 7)
710
711 #define PUSHEVAL(cx,n)                                                  \
712     STMT_START {                                                        \
713         assert(!(PL_in_eval & ~0x7F));                                  \
714         assert(!(PL_op->op_type & ~0x1FF));                             \
715         cx->blk_u16 = (PL_in_eval & 0x7F) | ((U16)PL_op->op_type << 7); \
716         cx->blk_eval.old_namesv = (n ? newSVpv(n,0) : NULL);            \
717         cx->blk_eval.old_eval_root = PL_eval_root;                      \
718         cx->blk_eval.cur_text = PL_parser ? PL_parser->linestr : NULL;  \
719         cx->blk_eval.cv = NULL; /* set by doeval(), as applicable */    \
720         cx->blk_eval.retop = NULL;                                      \
721         cx->blk_eval.cur_top_env = PL_top_env;                          \
722     } STMT_END
723
724 #define POPEVAL(cx)                                                     \
725     STMT_START {                                                        \
726         PL_in_eval = CxOLD_IN_EVAL(cx);                                 \
727         optype = CxOLD_OP_TYPE(cx);                                     \
728         PL_eval_root = cx->blk_eval.old_eval_root;                      \
729         if (cx->blk_eval.cur_text && SvSCREAM(cx->blk_eval.cur_text))   \
730             SvREFCNT_dec_NN(cx->blk_eval.cur_text);                     \
731         if (cx->blk_eval.old_namesv)                                    \
732             sv_2mortal(cx->blk_eval.old_namesv);                        \
733     } STMT_END
734
735 /* loop context */
736 struct block_loop {
737     I32         resetsp;
738     LOOP *      my_op;  /* My op, that contains redo, next and last ops.  */
739     union {     /* different ways of locating the iteration variable */
740         SV      **svp;
741         GV      *gv;
742         PAD     *oldcomppad; /* only used in ITHREADS */
743     } itervar_u;
744     union {
745         struct { /* valid if type is LOOP_FOR or LOOP_PLAIN (but {NULL,0})*/
746             AV * ary; /* use the stack if this is NULL */
747             IV ix;
748         } ary;
749         struct { /* valid if type is LOOP_LAZYIV */
750             IV cur;
751             IV end;
752         } lazyiv;
753         struct { /* valid if type if LOOP_LAZYSV */
754             SV * cur;
755             SV * end; /* maxiumum value (or minimum in reverse) */
756         } lazysv;
757     } state_u;
758 };
759
760 #ifdef USE_ITHREADS
761 #  define CxITERVAR_PADSV(c) \
762         &CX_CURPAD_SV( (c)->blk_loop.itervar_u, (c)->blk_loop.my_op->op_targ)
763 #else
764 #  define CxITERVAR_PADSV(c) ((c)->blk_loop.itervar_u.svp)
765 #endif
766
767 #define CxITERVAR(c)                                                    \
768         ((c)->blk_loop.itervar_u.oldcomppad                             \
769          ? (CxPADLOOP(c)                                                \
770             ? CxITERVAR_PADSV(c)                                        \
771             : isGV((c)->blk_loop.itervar_u.gv)                          \
772                 ? &GvSV((c)->blk_loop.itervar_u.gv)                     \
773                 : (SV **)&(c)->blk_loop.itervar_u.gv)                   \
774          : (SV**)NULL)
775
776 #define CxLABEL(c)      (0 + CopLABEL((c)->blk_oldcop))
777 #define CxLABEL_len(c,len)      (0 + CopLABEL_len((c)->blk_oldcop, len))
778 #define CxLABEL_len_flags(c,len,flags)  (0 + CopLABEL_len_flags((c)->blk_oldcop, len, flags))
779 #define CxHASARGS(c)    (((c)->cx_type & CXp_HASARGS) == CXp_HASARGS)
780 #define CxLVAL(c)       (0 + ((c)->blk_u16 & 0xff))
781 /* POPSUB has already been performed on this context frame */
782 #define CxPOPSUB_DONE 0x100
783
784
785 #define PUSHLOOP_PLAIN(cx, s)                                           \
786         cx->blk_loop.resetsp = s - PL_stack_base;                       \
787         cx->blk_loop.my_op = cLOOP;                                     \
788         cx->blk_loop.state_u.ary.ary = NULL;                            \
789         cx->blk_loop.state_u.ary.ix = 0;                                \
790         cx->blk_loop.itervar_u.svp = NULL;
791
792 #define PUSHLOOP_FOR(cx, ivar, s)                                       \
793         cx->blk_loop.resetsp = s - PL_stack_base;                       \
794         cx->blk_loop.my_op = cLOOP;                                     \
795         cx->blk_loop.state_u.ary.ary = NULL;                            \
796         cx->blk_loop.state_u.ary.ix = 0;                                \
797         cx->blk_loop.itervar_u.svp = (SV**)(ivar);
798
799 #define POPLOOP(cx)                                                     \
800         if (CxTYPE(cx) == CXt_LOOP_LAZYSV) {                            \
801             SvREFCNT_dec_NN(cx->blk_loop.state_u.lazysv.cur);           \
802             SvREFCNT_dec_NN(cx->blk_loop.state_u.lazysv.end);           \
803         }                                                               \
804         if (CxTYPE(cx) == CXt_LOOP_FOR)                                 \
805             SvREFCNT_dec(cx->blk_loop.state_u.ary.ary);
806
807 /* given/when context */
808 struct block_givwhen {
809         OP *leave_op;
810 };
811
812 #define PUSHGIVEN(cx)                                                   \
813         cx->blk_givwhen.leave_op = cLOGOP->op_other;
814
815 #define PUSHWHEN PUSHGIVEN
816
817 /* context common to subroutines, evals and loops */
818 struct block {
819     U8          blku_type;      /* what kind of context this is */
820     U8          blku_gimme;     /* is this block running in list context? */
821     U16         blku_u16;       /* used by block_sub and block_eval (so far) */
822     I32         blku_oldsp;     /* stack pointer to copy stuff down to */
823     COP *       blku_oldcop;    /* old curcop pointer */
824     I32         blku_oldmarksp; /* mark stack index */
825     I32         blku_oldscopesp;        /* scope stack index */
826     PMOP *      blku_oldpm;     /* values of pattern match vars */
827
828     union {
829         struct block_sub        blku_sub;
830         struct block_format     blku_format;
831         struct block_eval       blku_eval;
832         struct block_loop       blku_loop;
833         struct block_givwhen    blku_givwhen;
834     } blk_u;
835 };
836 #define blk_oldsp       cx_u.cx_blk.blku_oldsp
837 #define blk_oldcop      cx_u.cx_blk.blku_oldcop
838 #define blk_oldmarksp   cx_u.cx_blk.blku_oldmarksp
839 #define blk_oldscopesp  cx_u.cx_blk.blku_oldscopesp
840 #define blk_oldpm       cx_u.cx_blk.blku_oldpm
841 #define blk_gimme       cx_u.cx_blk.blku_gimme
842 #define blk_u16         cx_u.cx_blk.blku_u16
843 #define blk_sub         cx_u.cx_blk.blk_u.blku_sub
844 #define blk_format      cx_u.cx_blk.blk_u.blku_format
845 #define blk_eval        cx_u.cx_blk.blk_u.blku_eval
846 #define blk_loop        cx_u.cx_blk.blk_u.blku_loop
847 #define blk_givwhen     cx_u.cx_blk.blk_u.blku_givwhen
848
849 #define DEBUG_CX(action)                                                \
850     DEBUG_l(                                                            \
851         Perl_deb(aTHX_ "CX %ld %s %s (scope %ld,%ld) at %s:%d\n",       \
852                     (long)cxstack_ix,                                   \
853                     action,                                             \
854                     PL_block_type[CxTYPE(&cxstack[cxstack_ix])],        \
855                     (long)PL_scopestack_ix,                             \
856                     (long)(cxstack[cxstack_ix].blk_oldscopesp),         \
857                     __FILE__, __LINE__));
858
859 /* Enter a block. */
860 #define PUSHBLOCK(cx,t,sp) CXINC, cx = &cxstack[cxstack_ix],            \
861         cx->cx_type             = t,                                    \
862         cx->blk_oldsp           = sp - PL_stack_base,                   \
863         cx->blk_oldcop          = PL_curcop,                            \
864         cx->blk_oldmarksp       = PL_markstack_ptr - PL_markstack,      \
865         cx->blk_oldscopesp      = PL_scopestack_ix,                     \
866         cx->blk_oldpm           = PL_curpm,                             \
867         cx->blk_gimme           = (U8)gimme;                            \
868         DEBUG_CX("PUSH");
869
870 /* Exit a block (RETURN and LAST). */
871 #define POPBLOCK(cx,pm)                                                 \
872         DEBUG_CX("POP");                                                \
873         cx = &cxstack[cxstack_ix--],                                    \
874         newsp            = PL_stack_base + cx->blk_oldsp,               \
875         PL_curcop        = cx->blk_oldcop,                              \
876         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
877         PL_scopestack_ix = cx->blk_oldscopesp,                          \
878         pm               = cx->blk_oldpm,                               \
879         gimme            = cx->blk_gimme;
880
881 /* Continue a block elsewhere (NEXT and REDO). */
882 #define TOPBLOCK(cx)                                                    \
883         DEBUG_CX("TOP");                                                \
884         cx  = &cxstack[cxstack_ix],                                     \
885         PL_stack_sp      = PL_stack_base + cx->blk_oldsp,               \
886         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
887         PL_scopestack_ix = cx->blk_oldscopesp,                          \
888         PL_curpm         = cx->blk_oldpm;
889
890 /* substitution context */
891 struct subst {
892     U8          sbu_type;       /* what kind of context this is */
893     U8          sbu_rflags;
894     U16         sbu_rxtainted;  /* matches struct block */
895     I32         sbu_oldsave;
896     SSize_t     sbu_iters;
897     SSize_t     sbu_maxiters;
898     char *      sbu_orig;
899     SV *        sbu_dstr;
900     SV *        sbu_targ;
901     char *      sbu_s;
902     char *      sbu_m;
903     char *      sbu_strend;
904     void *      sbu_rxres;
905     REGEXP *    sbu_rx;
906 };
907 #define sb_iters        cx_u.cx_subst.sbu_iters
908 #define sb_maxiters     cx_u.cx_subst.sbu_maxiters
909 #define sb_rflags       cx_u.cx_subst.sbu_rflags
910 #define sb_oldsave      cx_u.cx_subst.sbu_oldsave
911 #define sb_rxtainted    cx_u.cx_subst.sbu_rxtainted
912 #define sb_orig         cx_u.cx_subst.sbu_orig
913 #define sb_dstr         cx_u.cx_subst.sbu_dstr
914 #define sb_targ         cx_u.cx_subst.sbu_targ
915 #define sb_s            cx_u.cx_subst.sbu_s
916 #define sb_m            cx_u.cx_subst.sbu_m
917 #define sb_strend       cx_u.cx_subst.sbu_strend
918 #define sb_rxres        cx_u.cx_subst.sbu_rxres
919 #define sb_rx           cx_u.cx_subst.sbu_rx
920
921 #ifdef PERL_CORE
922 #  define PUSHSUBST(cx) CXINC, cx = &cxstack[cxstack_ix],               \
923         cx->sb_iters            = iters,                                \
924         cx->sb_maxiters         = maxiters,                             \
925         cx->sb_rflags           = r_flags,                              \
926         cx->sb_oldsave          = oldsave,                              \
927         cx->sb_rxtainted        = rxtainted,                            \
928         cx->sb_orig             = orig,                                 \
929         cx->sb_dstr             = dstr,                                 \
930         cx->sb_targ             = targ,                                 \
931         cx->sb_s                = s,                                    \
932         cx->sb_m                = m,                                    \
933         cx->sb_strend           = strend,                               \
934         cx->sb_rxres            = NULL,                                 \
935         cx->sb_rx               = rx,                                   \
936         cx->cx_type             = CXt_SUBST | (once ? CXp_ONCE : 0);    \
937         rxres_save(&cx->sb_rxres, rx);                                  \
938         (void)ReREFCNT_inc(rx)
939
940 #  define POPSUBST(cx) cx = &cxstack[cxstack_ix--];                     \
941         rxres_free(&cx->sb_rxres);                                      \
942         ReREFCNT_dec(cx->sb_rx)
943 #endif
944
945 #define CxONCE(cx)              ((cx)->cx_type & CXp_ONCE)
946
947 struct context {
948     union {
949         struct block    cx_blk;
950         struct subst    cx_subst;
951     } cx_u;
952 };
953 #define cx_type cx_u.cx_subst.sbu_type
954
955 /* If you re-order these, there is also an array of uppercase names in perl.h
956    and a static array of context names in pp_ctl.c  */
957 #define CXTYPEMASK      0xf
958 #define CXt_NULL        0
959 #define CXt_WHEN        1
960 #define CXt_BLOCK       2
961 /* When micro-optimising :-) keep GIVEN next to the LOOPs, as these 5 share a
962    jump table in pp_ctl.c
963    The first 4 don't have a 'case' in at least one switch statement in pp_ctl.c
964 */
965 #define CXt_GIVEN       3
966 /* This is first so that CXt_LOOP_FOR|CXt_LOOP_LAZYIV is CXt_LOOP_LAZYIV */
967 #define CXt_LOOP_FOR    4
968 #define CXt_LOOP_PLAIN  5
969 #define CXt_LOOP_LAZYSV 6
970 #define CXt_LOOP_LAZYIV 7
971 #define CXt_SUB         8
972 #define CXt_FORMAT      9
973 #define CXt_EVAL       10
974 #define CXt_SUBST      11
975 /* SUBST doesn't feature in all switch statements.  */
976
977 /* private flags for CXt_SUB and CXt_NULL
978    However, this is checked in many places which do not check the type, so
979    this bit needs to be kept clear for most everything else. For reasons I
980    haven't investigated, it can coexist with CXp_FOR_DEF */
981 #define CXp_MULTICALL   0x10    /* part of a multicall (so don't
982                                    tear down context on exit). */ 
983
984 /* private flags for CXt_SUB and CXt_FORMAT */
985 #define CXp_HASARGS     0x20
986 #define CXp_SUB_RE      0x40    /* code called within regex, i.e. (?{}) */
987 #define CXp_SUB_RE_FAKE 0x80    /* fake sub CX for (?{}) in current scope */
988
989 /* private flags for CXt_EVAL */
990 #define CXp_REAL        0x20    /* truly eval'', not a lookalike */
991 #define CXp_TRYBLOCK    0x40    /* eval{}, not eval'' or similar */
992
993 /* private flags for CXt_LOOP */
994 #define CXp_FOR_DEF     0x10    /* foreach using $_ */
995 #define CXp_FOR_LVREF   0x20    /* foreach using \$var */
996 #define CxPADLOOP(c)    ((c)->blk_loop.my_op->op_targ)
997
998 /* private flags for CXt_SUBST */
999 #define CXp_ONCE        0x10    /* What was sbu_once in struct subst */
1000
1001 #define CxTYPE(c)       ((c)->cx_type & CXTYPEMASK)
1002 #define CxTYPE_is_LOOP(c)       (((c)->cx_type & 0xC) == 0x4)
1003 #define CxMULTICALL(c)  (((c)->cx_type & CXp_MULTICALL)                 \
1004                          == CXp_MULTICALL)
1005 #define CxREALEVAL(c)   (((c)->cx_type & (CXTYPEMASK|CXp_REAL))         \
1006                          == (CXt_EVAL|CXp_REAL))
1007 #define CxTRYBLOCK(c)   (((c)->cx_type & (CXTYPEMASK|CXp_TRYBLOCK))     \
1008                          == (CXt_EVAL|CXp_TRYBLOCK))
1009 #define CxFOREACH(c)    (CxTYPE_is_LOOP(c) && CxTYPE(c) != CXt_LOOP_PLAIN)
1010 #define CxFOREACHDEF(c) ((CxTYPE_is_LOOP(c) && CxTYPE(c) != CXt_LOOP_PLAIN) \
1011                          && ((c)->cx_type & CXp_FOR_DEF))
1012
1013 #define CXINC (cxstack_ix < cxstack_max ? ++cxstack_ix : (cxstack_ix = cxinc()))
1014
1015 /* 
1016 =head1 "Gimme" Values
1017 */
1018
1019 /*
1020 =for apidoc AmU||G_SCALAR
1021 Used to indicate scalar context.  See C<GIMME_V>, C<GIMME>, and
1022 L<perlcall>.
1023
1024 =for apidoc AmU||G_ARRAY
1025 Used to indicate list context.  See C<GIMME_V>, C<GIMME> and
1026 L<perlcall>.
1027
1028 =for apidoc AmU||G_VOID
1029 Used to indicate void context.  See C<GIMME_V> and L<perlcall>.
1030
1031 =for apidoc AmU||G_DISCARD
1032 Indicates that arguments returned from a callback should be discarded.  See
1033 L<perlcall>.
1034
1035 =for apidoc AmU||G_EVAL
1036
1037 Used to force a Perl C<eval> wrapper around a callback.  See
1038 L<perlcall>.
1039
1040 =for apidoc AmU||G_NOARGS
1041
1042 Indicates that no arguments are being sent to a callback.  See
1043 L<perlcall>.
1044
1045 =cut
1046 */
1047
1048 #define G_SCALAR        2
1049 #define G_ARRAY         3
1050 #define G_VOID          1
1051 #define G_WANT          3
1052
1053 /* extra flags for Perl_call_* routines */
1054 #define G_DISCARD       4       /* Call FREETMPS.
1055                                    Don't change this without consulting the
1056                                    hash actions codes defined in hv.h */
1057 #define G_EVAL          8       /* Assume eval {} around subroutine call. */
1058 #define G_NOARGS       16       /* Don't construct a @_ array. */
1059 #define G_KEEPERR      32       /* Warn for errors, don't overwrite $@ */
1060 #define G_NODEBUG      64       /* Disable debugging at toplevel.  */
1061 #define G_METHOD      128       /* Calling method. */
1062 #define G_FAKINGEVAL  256       /* Faking an eval context for call_sv or
1063                                    fold_constants. */
1064 #define G_UNDEF_FILL  512       /* Fill the stack with &PL_sv_undef
1065                                    A special case for UNSHIFT in
1066                                    Perl_magic_methcall().  */
1067 #define G_WRITING_TO_STDERR 1024 /* Perl_write_to_stderr() is calling
1068                                     Perl_magic_methcall().  */
1069 #define G_RE_REPARSING 0x800     /* compiling a run-time /(?{..})/ */
1070 #define G_METHOD_NAMED 4096     /* calling named method, eg without :: or ' */
1071
1072 /* flag bits for PL_in_eval */
1073 #define EVAL_NULL       0       /* not in an eval */
1074 #define EVAL_INEVAL     1       /* some enclosing scope is an eval */
1075 #define EVAL_WARNONLY   2       /* used by yywarn() when calling yyerror() */
1076 #define EVAL_KEEPERR    4       /* set by Perl_call_sv if G_KEEPERR */
1077 #define EVAL_INREQUIRE  8       /* The code is being required. */
1078 #define EVAL_RE_REPARSING 0x10  /* eval_sv() called with G_RE_REPARSING */
1079
1080 /* Support for switching (stack and block) contexts.
1081  * This ensures magic doesn't invalidate local stack and cx pointers.
1082  */
1083
1084 #define PERLSI_UNKNOWN          -1
1085 #define PERLSI_UNDEF            0
1086 #define PERLSI_MAIN             1
1087 #define PERLSI_MAGIC            2
1088 #define PERLSI_SORT             3
1089 #define PERLSI_SIGNAL           4
1090 #define PERLSI_OVERLOAD         5
1091 #define PERLSI_DESTROY          6
1092 #define PERLSI_WARNHOOK         7
1093 #define PERLSI_DIEHOOK          8
1094 #define PERLSI_REQUIRE          9
1095
1096 struct stackinfo {
1097     AV *                si_stack;       /* stack for current runlevel */
1098     PERL_CONTEXT *      si_cxstack;     /* context stack for runlevel */
1099     struct stackinfo *  si_prev;
1100     struct stackinfo *  si_next;
1101     I32                 si_cxix;        /* current context index */
1102     I32                 si_cxmax;       /* maximum allocated index */
1103     I32                 si_type;        /* type of runlevel */
1104     I32                 si_markoff;     /* offset where markstack begins for us.
1105                                          * currently used only with DEBUGGING,
1106                                          * but not #ifdef-ed for bincompat */
1107 };
1108
1109 typedef struct stackinfo PERL_SI;
1110
1111 #define cxstack         (PL_curstackinfo->si_cxstack)
1112 #define cxstack_ix      (PL_curstackinfo->si_cxix)
1113 #define cxstack_max     (PL_curstackinfo->si_cxmax)
1114
1115 #ifdef DEBUGGING
1116 #  define       SET_MARK_OFFSET \
1117     PL_curstackinfo->si_markoff = PL_markstack_ptr - PL_markstack
1118 #else
1119 #  define       SET_MARK_OFFSET NOOP
1120 #endif
1121
1122 #define PUSHSTACKi(type) \
1123     STMT_START {                                                        \
1124         PERL_SI *next = PL_curstackinfo->si_next;                       \
1125         DEBUG_l({                                                       \
1126             int i = 0; PERL_SI *p = PL_curstackinfo;                    \
1127             while (p) { i++; p = p->si_prev; }                          \
1128             Perl_deb(aTHX_ "push STACKINFO %d at %s:%d\n",              \
1129                          i, __FILE__, __LINE__);})                      \
1130         if (!next) {                                                    \
1131             next = new_stackinfo(32, 2048/sizeof(PERL_CONTEXT) - 1);    \
1132             next->si_prev = PL_curstackinfo;                            \
1133             PL_curstackinfo->si_next = next;                            \
1134         }                                                               \
1135         next->si_type = type;                                           \
1136         next->si_cxix = -1;                                             \
1137         AvFILLp(next->si_stack) = 0;                                    \
1138         SWITCHSTACK(PL_curstack,next->si_stack);                        \
1139         PL_curstackinfo = next;                                         \
1140         SET_MARK_OFFSET;                                                \
1141     } STMT_END
1142
1143 #define PUSHSTACK PUSHSTACKi(PERLSI_UNKNOWN)
1144
1145 /* POPSTACK works with PL_stack_sp, so it may need to be bracketed by
1146  * PUTBACK/SPAGAIN to flush/refresh any local SP that may be active */
1147 #define POPSTACK \
1148     STMT_START {                                                        \
1149         dSP;                                                            \
1150         PERL_SI * const prev = PL_curstackinfo->si_prev;                \
1151         DEBUG_l({                                                       \
1152             int i = -1; PERL_SI *p = PL_curstackinfo;                   \
1153             while (p) { i++; p = p->si_prev; }                          \
1154             Perl_deb(aTHX_ "pop  STACKINFO %d at %s:%d\n",              \
1155                          i, __FILE__, __LINE__);})                      \
1156         if (!prev) {                                                    \
1157             Perl_croak_popstack();                                      \
1158         }                                                               \
1159         SWITCHSTACK(PL_curstack,prev->si_stack);                        \
1160         /* don't free prev here, free them all at the END{} */          \
1161         PL_curstackinfo = prev;                                         \
1162     } STMT_END
1163
1164 #define POPSTACK_TO(s) \
1165     STMT_START {                                                        \
1166         while (PL_curstack != s) {                                      \
1167             dounwind(-1);                                               \
1168             POPSTACK;                                                   \
1169         }                                                               \
1170     } STMT_END
1171
1172 #define IN_PERL_COMPILETIME     (PL_curcop == &PL_compiling)
1173 #define IN_PERL_RUNTIME         (PL_curcop != &PL_compiling)
1174
1175 /*
1176 =head1 Multicall Functions
1177
1178 =for apidoc Ams||dMULTICALL
1179 Declare local variables for a multicall.  See L<perlcall/LIGHTWEIGHT CALLBACKS>.
1180
1181 =for apidoc Ams||PUSH_MULTICALL
1182 Opening bracket for a lightweight callback.
1183 See L<perlcall/LIGHTWEIGHT CALLBACKS>.
1184
1185 =for apidoc Ams||MULTICALL
1186 Make a lightweight callback.  See L<perlcall/LIGHTWEIGHT CALLBACKS>.
1187
1188 =for apidoc Ams||POP_MULTICALL
1189 Closing bracket for a lightweight callback.
1190 See L<perlcall/LIGHTWEIGHT CALLBACKS>.
1191
1192 =cut
1193 */
1194
1195 #define dMULTICALL \
1196     SV **newsp;                 /* set by POPBLOCK */                   \
1197     PERL_CONTEXT *cx;                                                   \
1198     CV *multicall_cv;                                                   \
1199     OP *multicall_cop;                                                  \
1200     bool multicall_oldcatch;                                            \
1201     U8 hasargs = 0              /* used by PUSHSUB */
1202
1203 #define PUSH_MULTICALL(the_cv) \
1204     PUSH_MULTICALL_FLAGS(the_cv, 0)
1205
1206 /* Like PUSH_MULTICALL, but allows you to specify extra flags
1207  * for the CX stack entry (this isn't part of the public API) */
1208
1209 #define PUSH_MULTICALL_FLAGS(the_cv, flags) \
1210     STMT_START {                                                        \
1211         CV * const _nOnclAshIngNamE_ = the_cv;                          \
1212         CV * const cv = _nOnclAshIngNamE_;                              \
1213         PADLIST * const padlist = CvPADLIST(cv);                        \
1214         ENTER;                                                          \
1215         multicall_oldcatch = CATCH_GET;                                 \
1216         SAVETMPS; SAVEVPTR(PL_op);                                      \
1217         CATCH_SET(TRUE);                                                \
1218         PUSHSTACKi(PERLSI_SORT);                                        \
1219         PUSHBLOCK(cx, (CXt_SUB|CXp_MULTICALL|flags), PL_stack_sp);      \
1220         PUSHSUB(cx);                                                    \
1221         if (!(flags & CXp_SUB_RE_FAKE))                                 \
1222             CvDEPTH(cv)++;                                              \
1223         if (CvDEPTH(cv) >= 2) {                                         \
1224             PERL_STACK_OVERFLOW_CHECK();                                \
1225             Perl_pad_push(aTHX_ padlist, CvDEPTH(cv));                  \
1226         }                                                               \
1227         SAVECOMPPAD();                                                  \
1228         PAD_SET_CUR_NOSAVE(padlist, CvDEPTH(cv));                       \
1229         multicall_cv = cv;                                              \
1230         multicall_cop = CvSTART(cv);                                    \
1231     } STMT_END
1232
1233 #define MULTICALL \
1234     STMT_START {                                                        \
1235         PL_op = multicall_cop;                                          \
1236         CALLRUNOPS(aTHX);                                               \
1237     } STMT_END
1238
1239 #define POP_MULTICALL \
1240     STMT_START {                                                        \
1241         cx = &cxstack[cxstack_ix];                                      \
1242         if (! ((CvDEPTH(multicall_cv) = cx->blk_sub.olddepth)) ) {      \
1243                 LEAVESUB(multicall_cv);                                 \
1244         }                                                               \
1245         POPBLOCK(cx,PL_curpm);                                          \
1246         POPSTACK;                                                       \
1247         CATCH_SET(multicall_oldcatch);                                  \
1248         LEAVE;                                                          \
1249         SPAGAIN;                                                        \
1250     } STMT_END
1251
1252 /* Change the CV of an already-pushed MULTICALL CxSUB block.
1253  * (this isn't part of the public API) */
1254
1255 #define CHANGE_MULTICALL_FLAGS(the_cv, flags) \
1256     STMT_START {                                                        \
1257         CV * const _nOnclAshIngNamE_ = the_cv;                          \
1258         CV * const cv = _nOnclAshIngNamE_;                              \
1259         PADLIST * const padlist = CvPADLIST(cv);                        \
1260         cx = &cxstack[cxstack_ix];                                      \
1261         assert(cx->cx_type & CXp_MULTICALL);                            \
1262         if (! ((CvDEPTH(multicall_cv) = cx->blk_sub.olddepth)) ) {      \
1263                 LEAVESUB(multicall_cv);                                 \
1264         }                                                               \
1265         cx->cx_type = (CXt_SUB|CXp_MULTICALL|flags);                    \
1266         PUSHSUB(cx);                                                    \
1267         if (!(flags & CXp_SUB_RE_FAKE))                                 \
1268             CvDEPTH(cv)++;                                              \
1269         if (CvDEPTH(cv) >= 2) {                                         \
1270             PERL_STACK_OVERFLOW_CHECK();                                \
1271             Perl_pad_push(aTHX_ padlist, CvDEPTH(cv));                  \
1272         }                                                               \
1273         SAVECOMPPAD();                                                  \
1274         PAD_SET_CUR_NOSAVE(padlist, CvDEPTH(cv));                       \
1275         multicall_cv = cv;                                              \
1276         multicall_cop = CvSTART(cv);                                    \
1277     } STMT_END
1278 /*
1279  * ex: set ts=8 sts=4 sw=4 et:
1280  */