More efficient API choices for string appending.
[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 by Larry Wall and others
5  *
6  *    You may distribute under the terms of either the GNU General Public
7  *    License or the Artistic License, as specified in the README file.
8  *
9  * Control ops (cops) are one of the three ops OP_NEXTSTATE, OP_DBSTATE,
10  * and OP_SETSTATE that (loosely speaking) are separate statements.
11  * They hold information important for lexical state and error reporting.
12  * At run time, PL_curcop is set to point to the most recently executed cop,
13  * and thus can be used to determine our current state.
14  */
15
16 /* A jmpenv packages the state required to perform a proper non-local jump.
17  * Note that there is a start_env initialized when perl starts, and top_env
18  * points to this initially, so top_env should always be non-null.
19  *
20  * Existence of a non-null top_env->je_prev implies it is valid to call
21  * longjmp() at that runlevel (we make sure start_env.je_prev is always
22  * null to ensure this).
23  *
24  * je_mustcatch, when set at any runlevel to TRUE, means eval ops must
25  * establish a local jmpenv to handle exception traps.  Care must be taken
26  * to restore the previous value of je_mustcatch before exiting the
27  * stack frame iff JMPENV_PUSH was not called in that stack frame.
28  * GSAR 97-03-27
29  */
30
31 struct jmpenv {
32     struct jmpenv *     je_prev;
33     Sigjmp_buf          je_buf;         /* only for use if !je_throw */
34     int                 je_ret;         /* last exception thrown */
35     bool                je_mustcatch;   /* need to call longjmp()? */
36 };
37
38 typedef struct jmpenv JMPENV;
39
40 #ifdef OP_IN_REGISTER
41 #define OP_REG_TO_MEM   PL_opsave = op
42 #define OP_MEM_TO_REG   op = PL_opsave
43 #else
44 #define OP_REG_TO_MEM   NOOP
45 #define OP_MEM_TO_REG   NOOP
46 #endif
47
48 /*
49  * How to build the first jmpenv.
50  *
51  * top_env needs to be non-zero. It points to an area
52  * in which longjmp() stuff is stored, as C callstack
53  * info there at least is thread specific this has to
54  * be per-thread. Otherwise a 'die' in a thread gives
55  * that thread the C stack of last thread to do an eval {}!
56  */
57
58 #define JMPENV_BOOTSTRAP \
59     STMT_START {                                \
60         Zero(&PL_start_env, 1, JMPENV);         \
61         PL_start_env.je_ret = -1;               \
62         PL_start_env.je_mustcatch = TRUE;       \
63         PL_top_env = &PL_start_env;             \
64     } STMT_END
65
66 /*
67  *   PERL_FLEXIBLE_EXCEPTIONS
68  * 
69  * All the flexible exceptions code has been removed.
70  * See the following threads for details:
71  *
72  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2004-07/msg00378.html
73  * 
74  * Joshua's original patches (which weren't applied) and discussion:
75  * 
76  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01396.html
77  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01489.html
78  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01491.html
79  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01608.html
80  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg02144.html
81  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg02998.html
82  * 
83  * Chip's reworked patch and discussion:
84  * 
85  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1999-03/msg00520.html
86  * 
87  * The flaw in these patches (which went unnoticed at the time) was
88  * that they moved some code that could potentially die() out of the
89  * region protected by the setjmp()s.  This caused exceptions within
90  * END blocks and such to not be handled by the correct setjmp().
91  * 
92  * The original patches that introduces flexible exceptions were:
93  *
94  *   http://public.activestate.com/cgi-bin/perlbrowse?patch=3386
95  *   http://public.activestate.com/cgi-bin/perlbrowse?patch=5162
96  */
97
98 #define dJMPENV         JMPENV cur_env
99
100 #define JMPENV_PUSH(v) \
101     STMT_START {                                                        \
102         DEBUG_l(Perl_deb(aTHX_ "Setting up jumplevel %p, was %p\n",     \
103                          (void*)&cur_env, (void*)PL_top_env));                  \
104         cur_env.je_prev = PL_top_env;                                   \
105         OP_REG_TO_MEM;                                                  \
106         cur_env.je_ret = PerlProc_setjmp(cur_env.je_buf, SCOPE_SAVES_SIGNAL_MASK);              \
107         OP_MEM_TO_REG;                                                  \
108         PL_top_env = &cur_env;                                          \
109         cur_env.je_mustcatch = FALSE;                                   \
110         (v) = cur_env.je_ret;                                           \
111     } STMT_END
112
113 #define JMPENV_POP \
114     STMT_START {                                                        \
115         DEBUG_l(Perl_deb(aTHX_ "popping jumplevel was %p, now %p\n",    \
116                          (void*)PL_top_env, (void*)cur_env.je_prev));                   \
117         PL_top_env = cur_env.je_prev;                                   \
118     } STMT_END
119
120 #define JMPENV_JUMP(v) \
121     STMT_START {                                                \
122         OP_REG_TO_MEM;                                          \
123         if (PL_top_env->je_prev)                                \
124             PerlProc_longjmp(PL_top_env->je_buf, (v));          \
125         if ((v) == 2)                                           \
126             PerlProc_exit(STATUS_EXIT);                         \
127         PerlIO_printf(PerlIO_stderr(), "panic: top_env\n");     \
128         PerlProc_exit(1);                                       \
129     } STMT_END
130
131 #define CATCH_GET               (PL_top_env->je_mustcatch)
132 #define CATCH_SET(v)            (PL_top_env->je_mustcatch = (v))
133
134
135 #include "mydtrace.h"
136
137 struct cop {
138     BASEOP
139     /* On LP64 putting this here takes advantage of the fact that BASEOP isn't
140        an exact multiple of 8 bytes to save structure padding.  */
141     line_t      cop_line;       /* line # of this command */
142     /* label for this construct is now stored in cop_hints_hash */
143 #ifdef USE_ITHREADS
144     char *      cop_stashpv;    /* package line was compiled in */
145     char *      cop_file;       /* file name the following line # is from */
146 #else
147     HV *        cop_stash;      /* package line was compiled in */
148     GV *        cop_filegv;     /* file the following line # is from */
149 #endif
150     U32         cop_hints;      /* hints bits from pragmata */
151     U32         cop_seq;        /* parse sequence number */
152     /* Beware. mg.c and warnings.pl assume the type of this is STRLEN *:  */
153     STRLEN *    cop_warnings;   /* lexical warnings bitmask */
154     /* compile time state of %^H.  See the comment in op.c for how this is
155        used to recreate a hash to return from caller.  */
156     struct refcounted_he * cop_hints_hash;
157 };
158
159 #ifdef USE_ITHREADS
160 #  define CopFILE(c)            ((c)->cop_file)
161 #  define CopFILEGV(c)          (CopFILE(c) \
162                                  ? gv_fetchfile(CopFILE(c)) : NULL)
163                                  
164 #  ifdef NETWARE
165 #    define CopFILE_set(c,pv)   ((c)->cop_file = savepv(pv))
166 #    define CopFILE_setn(c,pv,l)  ((c)->cop_file = savepv((pv),(l)))
167 #  else
168 #    define CopFILE_set(c,pv)   ((c)->cop_file = savesharedpv(pv))
169 #    define CopFILE_setn(c,pv,l)  ((c)->cop_file = savesharedpvn((pv),(l)))
170 #  endif
171
172 #  define CopFILESV(c)          (CopFILE(c) \
173                                  ? GvSV(gv_fetchfile(CopFILE(c))) : NULL)
174 #  define CopFILEAV(c)          (CopFILE(c) \
175                                  ? GvAV(gv_fetchfile(CopFILE(c))) : NULL)
176 #  ifdef DEBUGGING
177 #    define CopFILEAVx(c)       (assert(CopFILE(c)), \
178                                    GvAV(gv_fetchfile(CopFILE(c))))
179 #  else
180 #    define CopFILEAVx(c)       (GvAV(gv_fetchfile(CopFILE(c))))
181 #  endif
182 #  define CopSTASHPV(c)         ((c)->cop_stashpv)
183
184 #  ifdef NETWARE
185 #    define CopSTASHPV_set(c,pv)        ((c)->cop_stashpv = ((pv) ? savepv(pv) : NULL))
186 #  else
187 #    define CopSTASHPV_set(c,pv)        ((c)->cop_stashpv = savesharedpv(pv))
188 #  endif
189
190 #  define CopSTASH(c)           (CopSTASHPV(c) \
191                                  ? gv_stashpv(CopSTASHPV(c),GV_ADD) : NULL)
192 #  define CopSTASH_set(c,hv)    CopSTASHPV_set(c, (hv) ? HvNAME_get(hv) : NULL)
193 #  define CopSTASH_eq(c,hv)     ((hv) && stashpv_hvname_match(c,hv))
194 #  ifdef NETWARE
195 #    define CopSTASH_free(c) SAVECOPSTASH_FREE(c)
196 #    define CopFILE_free(c) SAVECOPFILE_FREE(c)
197 #  else
198 #    define CopSTASH_free(c)    PerlMemShared_free(CopSTASHPV(c))
199 #    define CopFILE_free(c)     (PerlMemShared_free(CopFILE(c)),(CopFILE(c) = NULL))
200 #  endif
201 #else
202 #  define CopFILEGV(c)          ((c)->cop_filegv)
203 #  define CopFILEGV_set(c,gv)   ((c)->cop_filegv = (GV*)SvREFCNT_inc(gv))
204 #  define CopFILE_set(c,pv)     CopFILEGV_set((c), gv_fetchfile(pv))
205 #  define CopFILE_setn(c,pv,l)  CopFILEGV_set((c), gv_fetchfile_flags((pv),(l),0))
206 #  define CopFILESV(c)          (CopFILEGV(c) ? GvSV(CopFILEGV(c)) : NULL)
207 #  define CopFILEAV(c)          (CopFILEGV(c) ? GvAV(CopFILEGV(c)) : NULL)
208 #  ifdef DEBUGGING
209 #    define CopFILEAVx(c)       (assert(CopFILEGV(c)), GvAV(CopFILEGV(c)))
210 #  else
211 #    define CopFILEAVx(c)       (GvAV(CopFILEGV(c)))
212 # endif
213 #  define CopFILE(c)            (CopFILEGV(c) && GvSV(CopFILEGV(c)) \
214                                     ? SvPVX(GvSV(CopFILEGV(c))) : NULL)
215 #  define CopSTASH(c)           ((c)->cop_stash)
216 #  define CopSTASH_set(c,hv)    ((c)->cop_stash = (hv))
217 #  define CopSTASHPV(c)         (CopSTASH(c) ? HvNAME_get(CopSTASH(c)) : NULL)
218    /* cop_stash is not refcounted */
219 #  define CopSTASHPV_set(c,pv)  CopSTASH_set((c), gv_stashpv(pv,GV_ADD))
220 #  define CopSTASH_eq(c,hv)     (CopSTASH(c) == (hv))
221 #  define CopSTASH_free(c)      
222 #  define CopFILE_free(c)       (SvREFCNT_dec(CopFILEGV(c)),(CopFILEGV(c) = NULL))
223
224 #endif /* USE_ITHREADS */
225 #define CopLABEL(c)  Perl_fetch_cop_label(aTHX_ (c)->cop_hints_hash, NULL, NULL)
226 #define CopLABEL_alloc(pv)      ((pv)?savepv(pv):NULL)
227
228 #define CopSTASH_ne(c,hv)       (!CopSTASH_eq(c,hv))
229 #define CopLINE(c)              ((c)->cop_line)
230 #define CopLINE_inc(c)          (++CopLINE(c))
231 #define CopLINE_dec(c)          (--CopLINE(c))
232 #define CopLINE_set(c,l)        (CopLINE(c) = (l))
233
234 /* OutCopFILE() is CopFILE for output (caller, die, warn, etc.) */
235 #ifdef MACOS_TRADITIONAL
236 #  define OutCopFILE(c) MacPerl_MPWFileName(CopFILE(c))
237 #else
238 #  define OutCopFILE(c) CopFILE(c)
239 #endif
240
241 /* If $[ is non-zero, it's stored in cop_hints under the key "$[", and
242    HINT_ARYBASE is set to indicate this.
243    Setting it is ineficient due to the need to create 2 mortal SVs, but as
244    using $[ is highly discouraged, no sane Perl code will be using it.  */
245 #define CopARYBASE_get(c)       \
246         ((CopHINTS_get(c) & HINT_ARYBASE)                               \
247          ? SvIV(Perl_refcounted_he_fetch(aTHX_ (c)->cop_hints_hash, 0,  \
248                                          "$[", 2, 0, 0))                \
249          : 0)
250 #define CopARYBASE_set(c, b) STMT_START { \
251         if (b || ((c)->cop_hints & HINT_ARYBASE)) {                     \
252             (c)->cop_hints |= HINT_ARYBASE;                             \
253             if ((c) == &PL_compiling)                                   \
254                 PL_hints |= HINT_LOCALIZE_HH | HINT_ARYBASE;            \
255             (c)->cop_hints_hash                                         \
256                = Perl_refcounted_he_new(aTHX_ (c)->cop_hints_hash,      \
257                                         newSVpvs_flags("$[", SVs_TEMP), \
258                                         sv_2mortal(newSViv(b)));        \
259         }                                                               \
260     } STMT_END
261
262 /* FIXME NATIVE_HINTS if this is changed from op_private (see perl.h)  */
263 #define CopHINTS_get(c)         ((c)->cop_hints + 0)
264 #define CopHINTS_set(c, h)      STMT_START {                            \
265                                     (c)->cop_hints = (h);               \
266                                 } STMT_END
267
268 /*
269  * Here we have some enormously heavy (or at least ponderous) wizardry.
270  */
271
272 /* subroutine context */
273 struct block_sub {
274     OP *        retop;  /* op to execute on exit from sub */
275     /* Above here is the same for sub, format and eval.  */
276     CV *        cv;
277     /* Above here is the same for sub and format.  */
278     AV *        savearray;
279     AV *        argarray;
280     I32         olddepth;
281     PAD         *oldcomppad;
282 };
283
284
285 /* format context */
286 struct block_format {
287     OP *        retop;  /* op to execute on exit from sub */
288     /* Above here is the same for sub, format and eval.  */
289     CV *        cv;
290     /* Above here is the same for sub and format.  */
291     GV *        gv;
292     GV *        dfoutgv;
293 };
294
295 /* base for the next two macros. Don't use directly.
296  * Note that the refcnt of the cv is incremented twice;  The CX one is
297  * decremented by LEAVESUB, the other by LEAVE. */
298
299 #define PUSHSUB_BASE(cx)                                                \
300         ENTRY_PROBE(GvENAME(CvGV(cv)),                                  \
301                 CopFILE((const COP *)CvSTART(cv)),                      \
302                 CopLINE((const COP *)CvSTART(cv)));                     \
303                                                                         \
304         cx->blk_sub.cv = cv;                                            \
305         cx->blk_sub.olddepth = CvDEPTH(cv);                             \
306         cx->cx_type |= (hasargs) ? CXp_HASARGS : 0;                     \
307         cx->blk_sub.retop = NULL;                                       \
308         if (!CvDEPTH(cv)) {                                             \
309             SvREFCNT_inc_simple_void_NN(cv);                            \
310             SvREFCNT_inc_simple_void_NN(cv);                            \
311             SAVEFREESV(cv);                                             \
312         }
313
314
315 #define PUSHSUB(cx)                                                     \
316         PUSHSUB_BASE(cx)                                                \
317         cx->blk_u16 = PL_op->op_private &                               \
318                               (OPpLVAL_INTRO|OPpENTERSUB_INARGS);
319
320 /* variant for use by OP_DBSTATE, where op_private holds hint bits */
321 #define PUSHSUB_DB(cx)                                                  \
322         PUSHSUB_BASE(cx)                                                \
323         cx->blk_u16 = 0;
324
325
326 #define PUSHFORMAT(cx, retop)                                           \
327         cx->blk_format.cv = cv;                                         \
328         cx->blk_format.gv = gv;                                         \
329         cx->blk_format.retop = (retop);                                 \
330         cx->blk_format.dfoutgv = PL_defoutgv;                           \
331         SvREFCNT_inc_void(cx->blk_format.dfoutgv)
332
333 #define POP_SAVEARRAY()                                         \
334     STMT_START {                                                        \
335         SvREFCNT_dec(GvAV(PL_defgv));                                   \
336         GvAV(PL_defgv) = cx->blk_sub.savearray;                         \
337     } STMT_END
338
339 /* junk in @_ spells trouble when cloning CVs and in pp_caller(), so don't
340  * leave any (a fast av_clear(ary), basically) */
341 #define CLEAR_ARGARRAY(ary) \
342     STMT_START {                                                        \
343         AvMAX(ary) += AvARRAY(ary) - AvALLOC(ary);                      \
344         AvARRAY(ary) = AvALLOC(ary);                                    \
345         AvFILLp(ary) = -1;                                              \
346     } STMT_END
347
348 #define POPSUB(cx,sv)                                                   \
349     STMT_START {                                                        \
350         RETURN_PROBE(GvENAME(CvGV((const CV*)cx->blk_sub.cv)),          \
351                 CopFILE((COP*)CvSTART((const CV*)cx->blk_sub.cv)),      \
352                 CopLINE((COP*)CvSTART((const CV*)cx->blk_sub.cv)));     \
353                                                                         \
354         if (CxHASARGS(cx)) {                                            \
355             POP_SAVEARRAY();                                            \
356             /* abandon @_ if it got reified */                          \
357             if (AvREAL(cx->blk_sub.argarray)) {                         \
358                 const SSize_t fill = AvFILLp(cx->blk_sub.argarray);     \
359                 SvREFCNT_dec(cx->blk_sub.argarray);                     \
360                 cx->blk_sub.argarray = newAV();                         \
361                 av_extend(cx->blk_sub.argarray, fill);                  \
362                 AvREIFY_only(cx->blk_sub.argarray);                     \
363                 CX_CURPAD_SV(cx->blk_sub, 0) = MUTABLE_SV(cx->blk_sub.argarray); \
364             }                                                           \
365             else {                                                      \
366                 CLEAR_ARGARRAY(cx->blk_sub.argarray);                   \
367             }                                                           \
368         }                                                               \
369         sv = MUTABLE_SV(cx->blk_sub.cv);                                \
370         if (sv && (CvDEPTH((const CV*)sv) = cx->blk_sub.olddepth))      \
371             sv = NULL;                                          \
372     } STMT_END
373
374 #define LEAVESUB(sv)                                                    \
375     STMT_START {                                                        \
376         if (sv)                                                         \
377             SvREFCNT_dec(sv);                                           \
378     } STMT_END
379
380 #define POPFORMAT(cx)                                                   \
381         setdefout(cx->blk_format.dfoutgv);                              \
382         SvREFCNT_dec(cx->blk_format.dfoutgv);
383
384 /* eval context */
385 struct block_eval {
386     OP *        retop;  /* op to execute on exit from eval */
387     /* Above here is the same for sub, format and eval.  */
388     SV *        old_namesv;
389     OP *        old_eval_root;
390     SV *        cur_text;
391     CV *        cv;
392     JMPENV *    cur_top_env; /* value of PL_top_env when eval CX created */
393 };
394
395 /* If we ever need more than 512 op types, change the shift from 7.
396    blku_gimme is actually also only 2 bits, so could be merged with something.
397 */
398
399 #define CxOLD_IN_EVAL(cx)       (((cx)->blk_u16) & 0x7F)
400 #define CxOLD_OP_TYPE(cx)       (((cx)->blk_u16) >> 7)
401
402 #define PUSHEVAL(cx,n)                                                  \
403     STMT_START {                                                        \
404         assert(!(PL_in_eval & ~0x7F));                                  \
405         assert(!(PL_op->op_type & ~0x1FF));                             \
406         cx->blk_u16 = (PL_in_eval & 0x7F) | ((U16)PL_op->op_type << 7); \
407         cx->blk_eval.old_namesv = (n ? newSVpv(n,0) : NULL);            \
408         cx->blk_eval.old_eval_root = PL_eval_root;                      \
409         cx->blk_eval.cur_text = PL_parser ? PL_parser->linestr : NULL;  \
410         cx->blk_eval.cv = NULL; /* set by doeval(), as applicable */    \
411         cx->blk_eval.retop = NULL;                                      \
412         cx->blk_eval.cur_top_env = PL_top_env;                          \
413     } STMT_END
414
415 #define POPEVAL(cx)                                                     \
416     STMT_START {                                                        \
417         PL_in_eval = CxOLD_IN_EVAL(cx);                                 \
418         optype = CxOLD_OP_TYPE(cx);                                     \
419         PL_eval_root = cx->blk_eval.old_eval_root;                      \
420         if (cx->blk_eval.old_namesv)                                    \
421             sv_2mortal(cx->blk_eval.old_namesv);                        \
422     } STMT_END
423
424 /* loop context */
425 struct block_loop {
426     I32         resetsp;
427     LOOP *      my_op;  /* My op, that contains redo, next and last ops.  */
428     /* (except for non_ithreads we need to modify next_op in pp_ctl.c, hence
429         why next_op is conditionally defined below.)  */
430 #ifdef USE_ITHREADS
431     PAD         *oldcomppad; /* Also used for the GV, if targoffset is 0 */
432     /* This is also accesible via cx->blk_loop.my_op->op_targ */
433     PADOFFSET   targoffset;
434 #else
435     OP *        next_op;
436     SV **       itervar;
437 #endif
438     union {
439         struct { /* valid if type is LOOP_FOR or LOOP_PLAIN (but {NULL,0})*/
440             AV * ary; /* use the stack if this is NULL */
441             IV ix;
442         } ary;
443         struct { /* valid if type is LOOP_LAZYIV */
444             IV cur;
445             IV end;
446         } lazyiv;
447         struct { /* valid if type if LOOP_LAZYSV */
448             SV * cur;
449             SV * end; /* maxiumum value (or minimum in reverse) */
450         } lazysv;
451     } state_u;
452 };
453
454 #ifdef USE_ITHREADS
455 #  define CxITERVAR(c)                                                  \
456         ((c)->blk_loop.oldcomppad                                       \
457          ? (CxPADLOOP(c)                                                \
458             ? &CX_CURPAD_SV( (c)->blk_loop, (c)->blk_loop.targoffset )  \
459             : &GvSV((GV*)(c)->blk_loop.oldcomppad))                     \
460          : (SV**)NULL)
461 #  define CX_ITERDATA_SET(cx,idata,o)                                   \
462         if ((cx->blk_loop.targoffset = (o)))                            \
463             CX_CURPAD_SAVE(cx->blk_loop);                               \
464         else                                                            \
465             cx->blk_loop.oldcomppad = (idata);
466 #else
467 #  define CxITERVAR(c)          ((c)->blk_loop.itervar)
468 #  define CX_ITERDATA_SET(cx,ivar,o)                                    \
469         cx->blk_loop.itervar = (SV**)(ivar);
470 #endif
471 #define CxLABEL(c)      (0 + CopLABEL((c)->blk_oldcop))
472 #define CxHASARGS(c)    (((c)->cx_type & CXp_HASARGS) == CXp_HASARGS)
473 #define CxLVAL(c)       (0 + (c)->blk_u16)
474
475 #ifdef USE_ITHREADS
476 #  define PUSHLOOP_OP_NEXT              /* No need to do anything.  */
477 #  define CX_LOOP_NEXTOP_GET(cx)        ((cx)->blk_loop.my_op->op_nextop + 0)
478 #else
479 #  define PUSHLOOP_OP_NEXT              cx->blk_loop.next_op = cLOOP->op_nextop
480 #  define CX_LOOP_NEXTOP_GET(cx)        ((cx)->blk_loop.next_op + 0)
481 #endif
482
483 #define PUSHLOOP_PLAIN(cx, s)                                           \
484         cx->blk_loop.resetsp = s - PL_stack_base;                       \
485         cx->blk_loop.my_op = cLOOP;                                     \
486         PUSHLOOP_OP_NEXT;                                               \
487         cx->blk_loop.state_u.ary.ary = NULL;                            \
488         cx->blk_loop.state_u.ary.ix = 0;                                \
489         CX_ITERDATA_SET(cx, NULL, 0);
490
491 #define PUSHLOOP_FOR(cx, dat, s, offset)                                \
492         cx->blk_loop.resetsp = s - PL_stack_base;                       \
493         cx->blk_loop.my_op = cLOOP;                                     \
494         PUSHLOOP_OP_NEXT;                                               \
495         cx->blk_loop.state_u.ary.ary = NULL;                            \
496         cx->blk_loop.state_u.ary.ix = 0;                                \
497         CX_ITERDATA_SET(cx, dat, offset);
498
499 #define POPLOOP(cx)                                                     \
500         if (CxTYPE(cx) == CXt_LOOP_LAZYSV) {                            \
501             SvREFCNT_dec(cx->blk_loop.state_u.lazysv.cur);              \
502             SvREFCNT_dec(cx->blk_loop.state_u.lazysv.end);              \
503         }                                                               \
504         if (CxTYPE(cx) == CXt_LOOP_FOR)                                 \
505             SvREFCNT_dec(cx->blk_loop.state_u.ary.ary);
506
507 /* given/when context */
508 struct block_givwhen {
509         OP *leave_op;
510 };
511
512 #define PUSHGIVEN(cx)                                                   \
513         cx->blk_givwhen.leave_op = cLOGOP->op_other;
514
515 #define PUSHWHEN PUSHGIVEN
516
517 /* context common to subroutines, evals and loops */
518 struct block {
519     U8          blku_type;      /* what kind of context this is */
520     U8          blku_gimme;     /* is this block running in list context? */
521     U16         blku_u16;       /* used by block_sub and block_eval (so far) */
522     I32         blku_oldsp;     /* stack pointer to copy stuff down to */
523     COP *       blku_oldcop;    /* old curcop pointer */
524     I32         blku_oldmarksp; /* mark stack index */
525     I32         blku_oldscopesp;        /* scope stack index */
526     PMOP *      blku_oldpm;     /* values of pattern match vars */
527
528     union {
529         struct block_sub        blku_sub;
530         struct block_format     blku_format;
531         struct block_eval       blku_eval;
532         struct block_loop       blku_loop;
533         struct block_givwhen    blku_givwhen;
534     } blk_u;
535 };
536 #define blk_oldsp       cx_u.cx_blk.blku_oldsp
537 #define blk_oldcop      cx_u.cx_blk.blku_oldcop
538 #define blk_oldmarksp   cx_u.cx_blk.blku_oldmarksp
539 #define blk_oldscopesp  cx_u.cx_blk.blku_oldscopesp
540 #define blk_oldpm       cx_u.cx_blk.blku_oldpm
541 #define blk_gimme       cx_u.cx_blk.blku_gimme
542 #define blk_u16         cx_u.cx_blk.blku_u16
543 #define blk_sub         cx_u.cx_blk.blk_u.blku_sub
544 #define blk_format      cx_u.cx_blk.blk_u.blku_format
545 #define blk_eval        cx_u.cx_blk.blk_u.blku_eval
546 #define blk_loop        cx_u.cx_blk.blk_u.blku_loop
547 #define blk_givwhen     cx_u.cx_blk.blk_u.blku_givwhen
548
549 /* Enter a block. */
550 #define PUSHBLOCK(cx,t,sp) CXINC, cx = &cxstack[cxstack_ix],            \
551         cx->cx_type             = t,                                    \
552         cx->blk_oldsp           = sp - PL_stack_base,                   \
553         cx->blk_oldcop          = PL_curcop,                            \
554         cx->blk_oldmarksp       = PL_markstack_ptr - PL_markstack,      \
555         cx->blk_oldscopesp      = PL_scopestack_ix,                     \
556         cx->blk_oldpm           = PL_curpm,                             \
557         cx->blk_gimme           = (U8)gimme;                            \
558         DEBUG_l( PerlIO_printf(Perl_debug_log, "Entering block %ld, type %s\n", \
559                     (long)cxstack_ix, PL_block_type[CxTYPE(cx)]); )
560
561 /* Exit a block (RETURN and LAST). */
562 #define POPBLOCK(cx,pm) cx = &cxstack[cxstack_ix--],                    \
563         newsp            = PL_stack_base + cx->blk_oldsp,               \
564         PL_curcop        = cx->blk_oldcop,                              \
565         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
566         PL_scopestack_ix = cx->blk_oldscopesp,                          \
567         pm               = cx->blk_oldpm,                               \
568         gimme            = cx->blk_gimme;                               \
569         DEBUG_SCOPE("POPBLOCK");                                        \
570         DEBUG_l( PerlIO_printf(Perl_debug_log, "Leaving block %ld, type %s\n",          \
571                     (long)cxstack_ix+1,PL_block_type[CxTYPE(cx)]); )
572
573 /* Continue a block elsewhere (NEXT and REDO). */
574 #define TOPBLOCK(cx) cx  = &cxstack[cxstack_ix],                        \
575         PL_stack_sp      = PL_stack_base + cx->blk_oldsp,               \
576         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
577         PL_scopestack_ix = cx->blk_oldscopesp,                          \
578         PL_curpm         = cx->blk_oldpm;                               \
579         DEBUG_SCOPE("TOPBLOCK");
580
581 /* substitution context */
582 struct subst {
583     U8          sbu_type;       /* what kind of context this is */
584     U8          sbu_rflags;
585     U16         sbu_rxtainted;  /* matches struct block */
586     I32         sbu_iters;
587     I32         sbu_maxiters;
588     I32         sbu_oldsave;
589     char *      sbu_orig;
590     SV *        sbu_dstr;
591     SV *        sbu_targ;
592     char *      sbu_s;
593     char *      sbu_m;
594     char *      sbu_strend;
595     void *      sbu_rxres;
596     REGEXP *    sbu_rx;
597 };
598 #define sb_iters        cx_u.cx_subst.sbu_iters
599 #define sb_maxiters     cx_u.cx_subst.sbu_maxiters
600 #define sb_rflags       cx_u.cx_subst.sbu_rflags
601 #define sb_oldsave      cx_u.cx_subst.sbu_oldsave
602 #define sb_once         cx_u.cx_subst.sbu_once
603 #define sb_rxtainted    cx_u.cx_subst.sbu_rxtainted
604 #define sb_orig         cx_u.cx_subst.sbu_orig
605 #define sb_dstr         cx_u.cx_subst.sbu_dstr
606 #define sb_targ         cx_u.cx_subst.sbu_targ
607 #define sb_s            cx_u.cx_subst.sbu_s
608 #define sb_m            cx_u.cx_subst.sbu_m
609 #define sb_strend       cx_u.cx_subst.sbu_strend
610 #define sb_rxres        cx_u.cx_subst.sbu_rxres
611 #define sb_rx           cx_u.cx_subst.sbu_rx
612
613 #ifdef PERL_CORE
614 #  define PUSHSUBST(cx) CXINC, cx = &cxstack[cxstack_ix],               \
615         cx->sb_iters            = iters,                                \
616         cx->sb_maxiters         = maxiters,                             \
617         cx->sb_rflags           = r_flags,                              \
618         cx->sb_oldsave          = oldsave,                              \
619         cx->sb_rxtainted        = rxtainted,                            \
620         cx->sb_orig             = orig,                                 \
621         cx->sb_dstr             = dstr,                                 \
622         cx->sb_targ             = targ,                                 \
623         cx->sb_s                = s,                                    \
624         cx->sb_m                = m,                                    \
625         cx->sb_strend           = strend,                               \
626         cx->sb_rxres            = NULL,                                 \
627         cx->sb_rx               = rx,                                   \
628         cx->cx_type             = CXt_SUBST | (once ? CXp_ONCE : 0);    \
629         rxres_save(&cx->sb_rxres, rx);                                  \
630         (void)ReREFCNT_inc(rx)
631
632 #  define POPSUBST(cx) cx = &cxstack[cxstack_ix--];                     \
633         rxres_free(&cx->sb_rxres);                                      \
634         ReREFCNT_dec(cx->sb_rx)
635 #endif
636
637 #define CxONCE(cx)              ((cx)->cx_type & CXp_ONCE)
638
639 struct context {
640     union {
641         struct block    cx_blk;
642         struct subst    cx_subst;
643     } cx_u;
644 };
645 #define cx_type cx_u.cx_subst.sbu_type
646
647 /* If you re-order these, there is also an array of uppercase names in perl.h
648    and a static array of context names in pp_ctl.c  */
649 #define CXTYPEMASK      0xf
650 #define CXt_NULL        0
651 #define CXt_WHEN        1
652 #define CXt_BLOCK       2
653 /* When micro-optimising :-) keep GIVEN next to the LOOPs, as these 5 share a
654    jump table in pp_ctl.c
655    The first 4 don't have a 'case' in at least one switch statement in pp_ctl.c
656 */
657 #define CXt_GIVEN       3
658 /* This is first so that CXt_LOOP_FOR|CXt_LOOP_LAZYIV is CXt_LOOP_LAZYIV */
659 #define CXt_LOOP_FOR    4
660 #define CXt_LOOP_PLAIN  5
661 #define CXt_LOOP_LAZYSV 6
662 #define CXt_LOOP_LAZYIV 7
663 #define CXt_SUB         8
664 #define CXt_FORMAT      9
665 #define CXt_EVAL       10
666 #define CXt_SUBST      11
667 /* SUBST doesn't feature in all switch statements.  */
668
669 /* private flags for CXt_SUB and CXt_NULL
670    However, this is checked in many places which do not check the type, so
671    this bit needs to be kept clear for most everything else. For reasons I
672    haven't investigated, it can coexist with CXp_FOR_DEF */
673 #define CXp_MULTICALL   0x10    /* part of a multicall (so don't
674                                    tear down context on exit). */ 
675
676 /* private flags for CXt_SUB and CXt_FORMAT */
677 #define CXp_HASARGS     0x20
678
679 /* private flags for CXt_EVAL */
680 #define CXp_REAL        0x20    /* truly eval'', not a lookalike */
681 #define CXp_TRYBLOCK    0x40    /* eval{}, not eval'' or similar */
682
683 /* private flags for CXt_LOOP */
684 #define CXp_FOR_DEF     0x10    /* foreach using $_ */
685 #ifdef USE_ITHREADS
686 #  define CxPADLOOP(c)  ((c)->blk_loop.targoffset)
687 #endif
688
689 /* private flags for CXt_SUBST */
690 #define CXp_ONCE        0x10    /* What was sbu_once in struct subst */
691
692 #define CxTYPE(c)       ((c)->cx_type & CXTYPEMASK)
693 #define CxTYPE_is_LOOP(c)       (((c)->cx_type & 0xC) == 0x4)
694 #define CxMULTICALL(c)  (((c)->cx_type & CXp_MULTICALL)                 \
695                          == CXp_MULTICALL)
696 #define CxREALEVAL(c)   (((c)->cx_type & (CXTYPEMASK|CXp_REAL))         \
697                          == (CXt_EVAL|CXp_REAL))
698 #define CxTRYBLOCK(c)   (((c)->cx_type & (CXTYPEMASK|CXp_TRYBLOCK))     \
699                          == (CXt_EVAL|CXp_TRYBLOCK))
700 #define CxFOREACH(c)    (CxTYPE_is_LOOP(c) && CxTYPE(c) != CXt_LOOP_PLAIN)
701 #define CxFOREACHDEF(c) ((CxTYPE_is_LOOP(c) && CxTYPE(c) != CXt_LOOP_PLAIN) \
702                          && ((c)->cx_type & CXp_FOR_DEF))
703
704 #define CXINC (cxstack_ix < cxstack_max ? ++cxstack_ix : (cxstack_ix = cxinc()))
705
706 /* 
707 =head1 "Gimme" Values
708 */
709
710 /*
711 =for apidoc AmU||G_SCALAR
712 Used to indicate scalar context.  See C<GIMME_V>, C<GIMME>, and
713 L<perlcall>.
714
715 =for apidoc AmU||G_ARRAY
716 Used to indicate list context.  See C<GIMME_V>, C<GIMME> and
717 L<perlcall>.
718
719 =for apidoc AmU||G_VOID
720 Used to indicate void context.  See C<GIMME_V> and L<perlcall>.
721
722 =for apidoc AmU||G_DISCARD
723 Indicates that arguments returned from a callback should be discarded.  See
724 L<perlcall>.
725
726 =for apidoc AmU||G_EVAL
727
728 Used to force a Perl C<eval> wrapper around a callback.  See
729 L<perlcall>.
730
731 =for apidoc AmU||G_NOARGS
732
733 Indicates that no arguments are being sent to a callback.  See
734 L<perlcall>.
735
736 =cut
737 */
738
739 #define G_SCALAR        2
740 #define G_ARRAY         3
741 #define G_VOID          1
742 #define G_WANT          3
743
744 /* extra flags for Perl_call_* routines */
745 #define G_DISCARD       4       /* Call FREETMPS.
746                                    Don't change this without consulting the
747                                    hash actions codes defined in hv.h */
748 #define G_EVAL          8       /* Assume eval {} around subroutine call. */
749 #define G_NOARGS       16       /* Don't construct a @_ array. */
750 #define G_KEEPERR      32       /* Append errors to $@, don't overwrite it */
751 #define G_NODEBUG      64       /* Disable debugging at toplevel.  */
752 #define G_METHOD      128       /* Calling method. */
753 #define G_FAKINGEVAL  256       /* Faking an eval context for call_sv or
754                                    fold_constants. */
755
756 /* flag bits for PL_in_eval */
757 #define EVAL_NULL       0       /* not in an eval */
758 #define EVAL_INEVAL     1       /* some enclosing scope is an eval */
759 #define EVAL_WARNONLY   2       /* used by yywarn() when calling yyerror() */
760 #define EVAL_KEEPERR    4       /* set by Perl_call_sv if G_KEEPERR */
761 #define EVAL_INREQUIRE  8       /* The code is being required. */
762
763 /* Support for switching (stack and block) contexts.
764  * This ensures magic doesn't invalidate local stack and cx pointers.
765  */
766
767 #define PERLSI_UNKNOWN          -1
768 #define PERLSI_UNDEF            0
769 #define PERLSI_MAIN             1
770 #define PERLSI_MAGIC            2
771 #define PERLSI_SORT             3
772 #define PERLSI_SIGNAL           4
773 #define PERLSI_OVERLOAD         5
774 #define PERLSI_DESTROY          6
775 #define PERLSI_WARNHOOK         7
776 #define PERLSI_DIEHOOK          8
777 #define PERLSI_REQUIRE          9
778
779 struct stackinfo {
780     AV *                si_stack;       /* stack for current runlevel */
781     PERL_CONTEXT *      si_cxstack;     /* context stack for runlevel */
782     struct stackinfo *  si_prev;
783     struct stackinfo *  si_next;
784     I32                 si_cxix;        /* current context index */
785     I32                 si_cxmax;       /* maximum allocated index */
786     I32                 si_type;        /* type of runlevel */
787     I32                 si_markoff;     /* offset where markstack begins for us.
788                                          * currently used only with DEBUGGING,
789                                          * but not #ifdef-ed for bincompat */
790 };
791
792 typedef struct stackinfo PERL_SI;
793
794 #define cxstack         (PL_curstackinfo->si_cxstack)
795 #define cxstack_ix      (PL_curstackinfo->si_cxix)
796 #define cxstack_max     (PL_curstackinfo->si_cxmax)
797
798 #ifdef DEBUGGING
799 #  define       SET_MARK_OFFSET \
800     PL_curstackinfo->si_markoff = PL_markstack_ptr - PL_markstack
801 #else
802 #  define       SET_MARK_OFFSET NOOP
803 #endif
804
805 #define PUSHSTACKi(type) \
806     STMT_START {                                                        \
807         PERL_SI *next = PL_curstackinfo->si_next;                       \
808         if (!next) {                                                    \
809             next = new_stackinfo(32, 2048/sizeof(PERL_CONTEXT) - 1);    \
810             next->si_prev = PL_curstackinfo;                            \
811             PL_curstackinfo->si_next = next;                            \
812         }                                                               \
813         next->si_type = type;                                           \
814         next->si_cxix = -1;                                             \
815         AvFILLp(next->si_stack) = 0;                                    \
816         SWITCHSTACK(PL_curstack,next->si_stack);                        \
817         PL_curstackinfo = next;                                         \
818         SET_MARK_OFFSET;                                                \
819     } STMT_END
820
821 #define PUSHSTACK PUSHSTACKi(PERLSI_UNKNOWN)
822
823 /* POPSTACK works with PL_stack_sp, so it may need to be bracketed by
824  * PUTBACK/SPAGAIN to flush/refresh any local SP that may be active */
825 #define POPSTACK \
826     STMT_START {                                                        \
827         dSP;                                                            \
828         PERL_SI * const prev = PL_curstackinfo->si_prev;                \
829         if (!prev) {                                                    \
830             PerlIO_printf(Perl_error_log, "panic: POPSTACK\n");         \
831             my_exit(1);                                                 \
832         }                                                               \
833         SWITCHSTACK(PL_curstack,prev->si_stack);                        \
834         /* don't free prev here, free them all at the END{} */          \
835         PL_curstackinfo = prev;                                         \
836     } STMT_END
837
838 #define POPSTACK_TO(s) \
839     STMT_START {                                                        \
840         while (PL_curstack != s) {                                      \
841             dounwind(-1);                                               \
842             POPSTACK;                                                   \
843         }                                                               \
844     } STMT_END
845
846 #define IN_PERL_COMPILETIME     (PL_curcop == &PL_compiling)
847 #define IN_PERL_RUNTIME         (PL_curcop != &PL_compiling)
848
849 /*
850 =head1 Multicall Functions
851
852 =for apidoc Ams||dMULTICALL
853 Declare local variables for a multicall. See L<perlcall/Lightweight Callbacks>.
854
855 =for apidoc Ams||PUSH_MULTICALL
856 Opening bracket for a lightweight callback.
857 See L<perlcall/Lightweight Callbacks>.
858
859 =for apidoc Ams||MULTICALL
860 Make a lightweight callback. See L<perlcall/Lightweight Callbacks>.
861
862 =for apidoc Ams||POP_MULTICALL
863 Closing bracket for a lightweight callback.
864 See L<perlcall/Lightweight Callbacks>.
865
866 =cut
867 */
868
869 #define dMULTICALL \
870     SV **newsp;                 /* set by POPBLOCK */                   \
871     PERL_CONTEXT *cx;                                                   \
872     CV *multicall_cv;                                                   \
873     OP *multicall_cop;                                                  \
874     bool multicall_oldcatch;                                            \
875     U8 hasargs = 0              /* used by PUSHSUB */
876
877 #define PUSH_MULTICALL(the_cv) \
878     STMT_START {                                                        \
879         CV * const _nOnclAshIngNamE_ = the_cv;                          \
880         CV * const cv = _nOnclAshIngNamE_;                              \
881         AV * const padlist = CvPADLIST(cv);                             \
882         ENTER;                                                          \
883         multicall_oldcatch = CATCH_GET;                                 \
884         SAVETMPS; SAVEVPTR(PL_op);                                      \
885         CATCH_SET(TRUE);                                                \
886         PUSHBLOCK(cx, CXt_SUB|CXp_MULTICALL, PL_stack_sp);              \
887         PUSHSUB(cx);                                                    \
888         if (++CvDEPTH(cv) >= 2) {                                       \
889             PERL_STACK_OVERFLOW_CHECK();                                \
890             Perl_pad_push(aTHX_ padlist, CvDEPTH(cv));                  \
891         }                                                               \
892         SAVECOMPPAD();                                                  \
893         PAD_SET_CUR_NOSAVE(padlist, CvDEPTH(cv));                       \
894         multicall_cv = cv;                                              \
895         multicall_cop = CvSTART(cv);                                    \
896     } STMT_END
897
898 #define MULTICALL \
899     STMT_START {                                                        \
900         PL_op = multicall_cop;                                          \
901         CALLRUNOPS(aTHX);                                               \
902     } STMT_END
903
904 #define POP_MULTICALL \
905     STMT_START {                                                        \
906         LEAVESUB(multicall_cv);                                         \
907         CvDEPTH(multicall_cv)--;                                        \
908         POPBLOCK(cx,PL_curpm);                                          \
909         CATCH_SET(multicall_oldcatch);                                  \
910         LEAVE;                                                          \
911     } STMT_END
912
913 /*
914  * Local variables:
915  * c-indentation-style: bsd
916  * c-basic-offset: 4
917  * indent-tabs-mode: t
918  * End:
919  *
920  * ex: set ts=8 sts=4 sw=4 noet:
921  */