cop.h

   1 /*    cop.h
   2  *
   3  *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
   4  *    2000, 2001, 2002, 2003, 2004, 2005, 2006 by Larry Wall and others
   5  *
   6  *    You may distribute under the terms of either the GNU General Public
   7  *    License or the Artistic License, as specified in the README file.
   8  *
   9  * Control ops (cops) are one of the three ops OP_NEXTSTATE, OP_DBSTATE,
  10  * and OP_SETSTATE that (loosely speaking) are separate statements.
  11  * They hold information important for lexical state and error reporting.
  12  * At run time, PL_curcop is set to point to the most recently executed cop,
  13  * and thus can be used to determine our current state.
  14  */
  15
  16 /* A jmpenv packages the state required to perform a proper non-local jump.
  17  * Note that there is a start_env initialized when perl starts, and top_env
  18  * points to this initially, so top_env should always be non-null.
  19  *
  20  * Existence of a non-null top_env->je_prev implies it is valid to call
  21  * longjmp() at that runlevel (we make sure start_env.je_prev is always
  22  * null to ensure this).
  23  *
  24  * je_mustcatch, when set at any runlevel to TRUE, means eval ops must
  25  * establish a local jmpenv to handle exception traps.  Care must be taken
  26  * to restore the previous value of je_mustcatch before exiting the
  27  * stack frame iff JMPENV_PUSH was not called in that stack frame.
  28  * GSAR 97-03-27
  29  */
  30
  31 struct jmpenv {
  32     struct jmpenv *     je_prev;
  33     Sigjmp_buf          je_buf;         /* only for use if !je_throw */
  34     int                 je_ret;         /* last exception thrown */
  35     bool                je_mustcatch;   /* need to call longjmp()? */
  36 };
  37
  38 typedef struct jmpenv JMPENV;
  39
  40 #ifdef OP_IN_REGISTER
  41 #define OP_REG_TO_MEM   PL_opsave = op
  42 #define OP_MEM_TO_REG   op = PL_opsave
  43 #else
  44 #define OP_REG_TO_MEM   NOOP
  45 #define OP_MEM_TO_REG   NOOP
  46 #endif
  47
  48 /*
  49  * How to build the first jmpenv.
  50  *
  51  * top_env needs to be non-zero. It points to an area
  52  * in which longjmp() stuff is stored, as C callstack
  53  * info there at least is thread specific this has to
  54  * be per-thread. Otherwise a 'die' in a thread gives
  55  * that thread the C stack of last thread to do an eval {}!
  56  */
  57
  58 #define JMPENV_BOOTSTRAP \
  59     STMT_START {                                \
  60         Zero(&PL_start_env, 1, JMPENV);         \
  61         PL_start_env.je_ret = -1;               \
  62         PL_start_env.je_mustcatch = TRUE;       \
  63         PL_top_env = &PL_start_env;             \
  64     } STMT_END
  65
  66 /*
  67  *   PERL_FLEXIBLE_EXCEPTIONS
  68  *
  69  * All the flexible exceptions code has been removed.
  70  * See the following threads for details:
  71  *
  72  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2004-07/msg00378.html
  73  *
  74  * Joshua's original patches (which weren't applied) and discussion:
  75  *
  76  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01396.html
  77  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01489.html
  78  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01491.html
  79  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01608.html
  80  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg02144.html
  81  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg02998.html
  82  *
  83  * Chip's reworked patch and discussion:
  84  *
  85  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1999-03/msg00520.html
  86  *
  87  * The flaw in these patches (which went unnoticed at the time) was
  88  * that they moved some code that could potentially die() out of the
  89  * region protected by the setjmp()s.  This caused exceptions within
  90  * END blocks and such to not be handled by the correct setjmp().
  91  *
  92  * The original patches that introduces flexible exceptions were:
  93  *
  94  *   http://public.activestate.com/cgi-bin/perlbrowse?patch=3386
  95  *   http://public.activestate.com/cgi-bin/perlbrowse?patch=5162
  96  */
  97
  98 #define dJMPENV         JMPENV cur_env
  99
 100 #define JMPENV_PUSH(v) \
 101     STMT_START {                                                        \
 102         DEBUG_l(Perl_deb(aTHX_ "Setting up jumplevel %p, was %p\n",     \
 103                          (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
 136 struct cop {
 137     BASEOP
 138     char *      cop_label;      /* label for this construct */
 139 #ifdef USE_ITHREADS
 140     char *      cop_stashpv;    /* package line was compiled in */
 141     char *      cop_file;       /* file name the following line # is from */
 142 #else
 143     HV *        cop_stash;      /* package line was compiled in */
 144     GV *        cop_filegv;     /* file the following line # is from */
 145 #endif
 146     U32         cop_hints;      /* hints bits from pragmata */
 147     U32         cop_seq;        /* parse sequence number */
 148     line_t      cop_line;       /* line # of this command */
 149     /* Beware. mg.c and warnings.pl assume the type of this is STRLEN *:  */
 150     STRLEN *    cop_warnings;   /* lexical warnings bitmask */
 151     /* compile time state of %^H.  See the comment in op.c for how this is
 152        used to recreate a hash to return from caller.  */
 153     struct refcounted_he * cop_hints_hash;
 154 };
 155
 156 #ifdef USE_ITHREADS
 157 #  define CopFILE(c)            ((c)->cop_file)
 158 #  define CopFILEGV(c)          (CopFILE(c) \
 159                                  ? gv_fetchfile(CopFILE(c)) : NULL)
 160
 161 #  ifdef NETWARE
 162 #    define CopFILE_set(c,pv)   ((c)->cop_file = savepv(pv))
 163 #  else
 164 #    define CopFILE_set(c,pv)   ((c)->cop_file = savesharedpv(pv))
 165 #  endif
 166
 167 #  define CopFILESV(c)          (CopFILE(c) \
 168                                  ? GvSV(gv_fetchfile(CopFILE(c))) : NULL)
 169 #  define CopFILEAV(c)          (CopFILE(c) \
 170                                  ? GvAV(gv_fetchfile(CopFILE(c))) : NULL)
 171 #  ifdef DEBUGGING
 172 #    define CopFILEAVx(c)       (assert(CopFILE(c)), \
 173                                    GvAV(gv_fetchfile(CopFILE(c))))
 174 #  else
 175 #    define CopFILEAVx(c)       (GvAV(gv_fetchfile(CopFILE(c))))
 176 #  endif
 177 #  define CopSTASHPV(c)         ((c)->cop_stashpv)
 178
 179 #  ifdef NETWARE
 180 #    define CopSTASHPV_set(c,pv)        ((c)->cop_stashpv = ((pv) ? savepv(pv) : NULL))
 181 #  else
 182 #    define CopSTASHPV_set(c,pv)        ((c)->cop_stashpv = savesharedpv(pv))
 183 #  endif
 184
 185 #  define CopSTASH(c)           (CopSTASHPV(c) \
 186                                  ? gv_stashpv(CopSTASHPV(c),GV_ADD) : NULL)
 187 #  define CopSTASH_set(c,hv)    CopSTASHPV_set(c, (hv) ? HvNAME_get(hv) : NULL)
 188 #  define CopSTASH_eq(c,hv)     ((hv) && stashpv_hvname_match(c,hv))
 189 #  ifdef NETWARE
 190 #    define CopSTASH_free(c) SAVECOPSTASH_FREE(c)
 191 #    define CopFILE_free(c) SAVECOPFILE_FREE(c)
 192 #  else
 193 #    define CopSTASH_free(c)    PerlMemShared_free(CopSTASHPV(c))
 194 #    define CopFILE_free(c)     (PerlMemShared_free(CopFILE(c)),(CopFILE(c) = NULL))
 195 #  endif
 196 #else
 197 #  define CopFILEGV(c)          ((c)->cop_filegv)
 198 #  define CopFILEGV_set(c,gv)   ((c)->cop_filegv = (GV*)SvREFCNT_inc(gv))
 199 #  define CopFILE_set(c,pv)     CopFILEGV_set((c), gv_fetchfile(pv))
 200 #  define CopFILESV(c)          (CopFILEGV(c) ? GvSV(CopFILEGV(c)) : NULL)
 201 #  define CopFILEAV(c)          (CopFILEGV(c) ? GvAV(CopFILEGV(c)) : NULL)
 202 #  ifdef DEBUGGING
 203 #    define CopFILEAVx(c)       (assert(CopFILEGV(c)), GvAV(CopFILEGV(c)))
 204 #  else
 205 #    define CopFILEAVx(c)       (GvAV(CopFILEGV(c)))
 206 # endif
 207 #  define CopFILE(c)            (CopFILESV(c) ? SvPVX(CopFILESV(c)) : NULL)
 208 #  define CopSTASH(c)           ((c)->cop_stash)
 209 #  define CopSTASH_set(c,hv)    ((c)->cop_stash = (hv))
 210 #  define CopSTASHPV(c)         (CopSTASH(c) ? HvNAME_get(CopSTASH(c)) : NULL)
 211    /* cop_stash is not refcounted */
 212 #  define CopSTASHPV_set(c,pv)  CopSTASH_set((c), gv_stashpv(pv,GV_ADD))
 213 #  define CopSTASH_eq(c,hv)     (CopSTASH(c) == (hv))
 214 #  define CopSTASH_free(c)
 215 #  define CopFILE_free(c)       (SvREFCNT_dec(CopFILEGV(c)),(CopFILEGV(c) = NULL))
 216
 217 #endif /* USE_ITHREADS */
 218
 219 #define CopSTASH_ne(c,hv)       (!CopSTASH_eq(c,hv))
 220 #define CopLINE(c)              ((c)->cop_line)
 221 #define CopLINE_inc(c)          (++CopLINE(c))
 222 #define CopLINE_dec(c)          (--CopLINE(c))
 223 #define CopLINE_set(c,l)        (CopLINE(c) = (l))
 224
 225 /* OutCopFILE() is CopFILE for output (caller, die, warn, etc.) */
 226 #ifdef MACOS_TRADITIONAL
 227 #  define OutCopFILE(c) MacPerl_MPWFileName(CopFILE(c))
 228 #else
 229 #  define OutCopFILE(c) CopFILE(c)
 230 #endif
 231
 232 /* If $[ is non-zero, it's stored in cop_hints under the key "$[", and
 233    HINT_ARYBASE is set to indicate this.
 234    Setting it is ineficient due to the need to create 2 mortal SVs, but as
 235    using $[ is highly discouraged, no sane Perl code will be using it.  */
 236 #define CopARYBASE_get(c)       \
 237         ((CopHINTS_get(c) & HINT_ARYBASE)                               \
 238          ? SvIV(Perl_refcounted_he_fetch(aTHX_ (c)->cop_hints_hash, 0,  \
 239                                          "$[", 2, 0, 0))                \
 240          : 0)
 241 #define CopARYBASE_set(c, b) STMT_START { \
 242         if (b || ((c)->cop_hints & HINT_ARYBASE)) {                     \
 243             (c)->cop_hints |= HINT_ARYBASE;                             \
 244             if ((c) == &PL_compiling)                                   \
 245                 PL_hints |= HINT_LOCALIZE_HH | HINT_ARYBASE;            \
 246             (c)->cop_hints_hash                                         \
 247                = Perl_refcounted_he_new(aTHX_ (c)->cop_hints_hash,      \
 248                                         sv_2mortal(newSVpvs("$[")),     \
 249                                         sv_2mortal(newSViv(b)));        \
 250         }                                                               \
 251     } STMT_END
 252
 253 /* FIXME NATIVE_HINTS if this is changed from op_private (see perl.h)  */
 254 #define CopHINTS_get(c)         ((c)->cop_hints + 0)
 255 #define CopHINTS_set(c, h)      STMT_START {                            \
 256                                     (c)->cop_hints = (h);               \
 257                                 } STMT_END
 258
 259 /*
 260  * Here we have some enormously heavy (or at least ponderous) wizardry.
 261  */
 262
 263 /* subroutine context */
 264 struct block_sub {
 265     CV *        cv;
 266     GV *        gv;
 267     GV *        dfoutgv;
 268     AV *        savearray;
 269     AV *        argarray;
 270     I32         olddepth;
 271     U8          hasargs;
 272     U8          lval;           /* XXX merge lval and hasargs? */
 273     PAD         *oldcomppad;
 274     OP *        retop;  /* op to execute on exit from sub */
 275 };
 276
 277 /* base for the next two macros. Don't use directly.
 278  * Note that the refcnt of the cv is incremented twice;  The CX one is
 279  * decremented by LEAVESUB, the other by LEAVE. */
 280
 281 #define PUSHSUB_BASE(cx)                                                \
 282         cx->blk_sub.cv = cv;                                            \
 283         cx->blk_sub.olddepth = CvDEPTH(cv);                             \
 284         cx->blk_sub.hasargs = hasargs;                                  \
 285         cx->blk_sub.retop = NULL;                                       \
 286         if (!CvDEPTH(cv)) {                                             \
 287             SvREFCNT_inc_simple_void_NN(cv);                            \
 288             SvREFCNT_inc_simple_void_NN(cv);                            \
 289             SAVEFREESV(cv);                                             \
 290         }
 291
 292
 293 #define PUSHSUB(cx)                                                     \
 294         PUSHSUB_BASE(cx)                                                \
 295         cx->blk_sub.lval = PL_op->op_private &                          \
 296                               (OPpLVAL_INTRO|OPpENTERSUB_INARGS);
 297
 298 /* variant for use by OP_DBSTATE, where op_private holds hint bits */
 299 #define PUSHSUB_DB(cx)                                                  \
 300         PUSHSUB_BASE(cx)                                                \
 301         cx->blk_sub.lval = 0;
 302
 303
 304 #define PUSHFORMAT(cx)                                                  \
 305         cx->blk_sub.cv = cv;                                            \
 306         cx->blk_sub.gv = gv;                                            \
 307         cx->blk_sub.retop = NULL;                                       \
 308         cx->blk_sub.hasargs = 0;                                        \
 309         cx->blk_sub.dfoutgv = PL_defoutgv;                              \
 310         SvREFCNT_inc_void(cx->blk_sub.dfoutgv)
 311
 312 #define POP_SAVEARRAY()                                         \
 313     STMT_START {                                                        \
 314         SvREFCNT_dec(GvAV(PL_defgv));                                   \
 315         GvAV(PL_defgv) = cx->blk_sub.savearray;                         \
 316     } STMT_END
 317
 318 /* junk in @_ spells trouble when cloning CVs and in pp_caller(), so don't
 319  * leave any (a fast av_clear(ary), basically) */
 320 #define CLEAR_ARGARRAY(ary) \
 321     STMT_START {                                                        \
 322         AvMAX(ary) += AvARRAY(ary) - AvALLOC(ary);                      \
 323         SvPV_set(ary, (char*)AvALLOC(ary));                             \
 324         AvFILLp(ary) = -1;                                              \
 325     } STMT_END
 326
 327 #define POPSUB(cx,sv)                                                   \
 328     STMT_START {                                                        \
 329         if (cx->blk_sub.hasargs) {                                      \
 330             POP_SAVEARRAY();                                            \
 331             /* abandon @_ if it got reified */                          \
 332             if (AvREAL(cx->blk_sub.argarray)) {                         \
 333                 const SSize_t fill = AvFILLp(cx->blk_sub.argarray);     \
 334                 SvREFCNT_dec(cx->blk_sub.argarray);                     \
 335                 cx->blk_sub.argarray = newAV();                         \
 336                 av_extend(cx->blk_sub.argarray, fill);                  \
 337                 AvREIFY_only(cx->blk_sub.argarray);                     \
 338                 CX_CURPAD_SV(cx->blk_sub, 0) = (SV*)cx->blk_sub.argarray;       \
 339             }                                                           \
 340             else {                                                      \
 341                 CLEAR_ARGARRAY(cx->blk_sub.argarray);                   \
 342             }                                                           \
 343         }                                                               \
 344         sv = (SV*)cx->blk_sub.cv;                                       \
 345         if (sv && (CvDEPTH((CV*)sv) = cx->blk_sub.olddepth))            \
 346             sv = NULL;                                          \
 347     } STMT_END
 348
 349 #define LEAVESUB(sv)                                                    \
 350     STMT_START {                                                        \
 351         if (sv)                                                         \
 352             SvREFCNT_dec(sv);                                           \
 353     } STMT_END
 354
 355 #define POPFORMAT(cx)                                                   \
 356         setdefout(cx->blk_sub.dfoutgv);                                 \
 357         SvREFCNT_dec(cx->blk_sub.dfoutgv);
 358
 359 /* eval context */
 360 struct block_eval {
 361     U8          old_in_eval;
 362     U16         old_op_type;
 363     SV *        old_namesv;
 364     OP *        old_eval_root;
 365     SV *        cur_text;
 366     CV *        cv;
 367     OP *        retop;  /* op to execute on exit from eval */
 368     JMPENV *    cur_top_env; /* value of PL_top_env when eval CX created */
 369 };
 370
 371 #define PUSHEVAL(cx,n,fgv)                                              \
 372     STMT_START {                                                        \
 373         cx->blk_eval.old_in_eval = PL_in_eval;                          \
 374         cx->blk_eval.old_op_type = PL_op->op_type;                      \
 375         cx->blk_eval.old_namesv = (n ? newSVpv(n,0) : NULL);            \
 376         cx->blk_eval.old_eval_root = PL_eval_root;                      \
 377         cx->blk_eval.cur_text = PL_linestr;                             \
 378         cx->blk_eval.cv = NULL; /* set by doeval(), as applicable */    \
 379         cx->blk_eval.retop = NULL;                                      \
 380         cx->blk_eval.cur_top_env = PL_top_env;                          \
 381     } STMT_END
 382
 383 #define POPEVAL(cx)                                                     \
 384     STMT_START {                                                        \
 385         PL_in_eval = cx->blk_eval.old_in_eval;                          \
 386         optype = cx->blk_eval.old_op_type;                              \
 387         PL_eval_root = cx->blk_eval.old_eval_root;                      \
 388         if (cx->blk_eval.old_namesv)                                    \
 389             sv_2mortal(cx->blk_eval.old_namesv);                        \
 390     } STMT_END
 391
 392 /* loop context */
 393 struct block_loop {
 394     char *      label;
 395     I32         resetsp;
 396     LOOP *      my_op;  /* My op, that contains redo, next and last ops.  */
 397     /* (except for non_ithreads we need to modify next_op in pp_ctl.c, hence
 398         why next_op is conditionally defined below.)  */
 399 #ifdef USE_ITHREADS
 400     void *      iterdata;
 401     PAD         *oldcomppad;
 402 #else
 403     OP *        next_op;
 404     SV **       itervar;
 405 #endif
 406     SV *        itersave;
 407     /* (from inspection of source code) for a .. range of strings this is the
 408        current string.  */
 409     SV *        iterlval;
 410     /* (from inspection of source code) for a foreach loop this is the array
 411        being iterated over. For a .. range of numbers it's the current value.
 412        A check is often made on the SvTYPE of iterary to determine whether
 413        we are iterating over an array or a range. (numbers or strings)  */
 414     AV *        iterary;
 415     IV          iterix;
 416     /* (from inspection of source code) for a .. range of numbers this is the
 417        maximum value.  */
 418     IV          itermax;
 419 };
 420 /* It might be possible to squeeze this structure further. As best I can tell
 421    itermax and iterlval are never used at the same time, so it might be possible
 422    to make them into a union. However, I'm not confident that there are enough
 423    flag bits/NULLable pointers in this structure alone to encode which is
 424    active. There is, however, U8 of space free in struct block, which could be
 425    used. Right now it may not be worth squeezing this structure further, as it's
 426    the largest part of struct block, and currently struct block is 64 bytes on
 427    an ILP32 system, which will give good cache alignment.
 428 */
 429
 430 #ifdef USE_ITHREADS
 431 #  define CxITERVAR(c)                                                  \
 432         ((c)->blk_loop.iterdata                                         \
 433          ? (CxPADLOOP(cx)                                               \
 434             ? &CX_CURPAD_SV( (c)->blk_loop,                             \
 435                     INT2PTR(PADOFFSET, (c)->blk_loop.iterdata))         \
 436             : &GvSV((GV*)(c)->blk_loop.iterdata))                       \
 437          : (SV**)NULL)
 438 #  define CX_ITERDATA_SET(cx,idata)                                     \
 439         CX_CURPAD_SAVE(cx->blk_loop);                                   \
 440         if ((cx->blk_loop.iterdata = (idata)))                          \
 441             cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));       \
 442         else                                                            \
 443             cx->blk_loop.itersave = NULL;
 444 #else
 445 #  define CxITERVAR(c)          ((c)->blk_loop.itervar)
 446 #  define CX_ITERDATA_SET(cx,ivar)                                      \
 447         if ((cx->blk_loop.itervar = (SV**)(ivar)))                      \
 448             cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));       \
 449         else                                                            \
 450             cx->blk_loop.itersave = NULL;
 451 #endif
 452
 453 #ifdef USE_ITHREADS
 454 #  define PUSHLOOP_OP_NEXT              /* No need to do anything.  */
 455 #  define CX_LOOP_NEXTOP_GET(cx)        ((cx)->blk_loop.my_op->op_nextop + 0)
 456 #else
 457 #  define PUSHLOOP_OP_NEXT              cx->blk_loop.next_op = cLOOP->op_nextop
 458 #  define CX_LOOP_NEXTOP_GET(cx)        ((cx)->blk_loop.next_op + 0)
 459 #endif
 460
 461 #define PUSHLOOP(cx, dat, s)                                            \
 462         cx->blk_loop.label = PL_curcop->cop_label;                      \
 463         cx->blk_loop.resetsp = s - PL_stack_base;                       \
 464         cx->blk_loop.my_op = cLOOP;                                     \
 465         PUSHLOOP_OP_NEXT;                                               \
 466         cx->blk_loop.iterlval = NULL;                                   \
 467         cx->blk_loop.iterary = NULL;                                    \
 468         cx->blk_loop.iterix = -1;                                       \
 469         CX_ITERDATA_SET(cx,dat);
 470
 471 #define POPLOOP(cx)                                                     \
 472         SvREFCNT_dec(cx->blk_loop.iterlval);                            \
 473         if (CxITERVAR(cx)) {                                            \
 474             if (SvPADMY(cx->blk_loop.itersave)) {                       \
 475                 SV ** const s_v_p = CxITERVAR(cx);                      \
 476                 sv_2mortal(*s_v_p);                                     \
 477                 *s_v_p = cx->blk_loop.itersave;                         \
 478             }                                                           \
 479             else {                                                      \
 480                 SvREFCNT_dec(cx->blk_loop.itersave);                    \
 481             }                                                           \
 482         }                                                               \
 483         if (cx->blk_loop.iterary && cx->blk_loop.iterary != PL_curstack)\
 484             SvREFCNT_dec(cx->blk_loop.iterary);
 485
 486 /* given/when context */
 487 struct block_givwhen {
 488         OP *leave_op;
 489 };
 490
 491 #define PUSHGIVEN(cx)                                                   \
 492         cx->blk_givwhen.leave_op = cLOGOP->op_other;
 493
 494 #define PUSHWHEN PUSHGIVEN
 495
 496 /* context common to subroutines, evals and loops */
 497 struct block {
 498     U16         blku_type;      /* what kind of context this is */
 499     U8          blku_gimme;     /* is this block running in list context? */
 500     I32         blku_oldsp;     /* stack pointer to copy stuff down to */
 501     COP *       blku_oldcop;    /* old curcop pointer */
 502     I32         blku_oldmarksp; /* mark stack index */
 503     I32         blku_oldscopesp;        /* scope stack index */
 504     PMOP *      blku_oldpm;     /* values of pattern match vars */
 505
 506     union {
 507         struct block_sub        blku_sub;
 508         struct block_eval       blku_eval;
 509         struct block_loop       blku_loop;
 510         struct block_givwhen    blku_givwhen;
 511     } blk_u;
 512 };
 513 #define blk_oldsp       cx_u.cx_blk.blku_oldsp
 514 #define blk_oldcop      cx_u.cx_blk.blku_oldcop
 515 #define blk_oldmarksp   cx_u.cx_blk.blku_oldmarksp
 516 #define blk_oldscopesp  cx_u.cx_blk.blku_oldscopesp
 517 #define blk_oldpm       cx_u.cx_blk.blku_oldpm
 518 #define blk_gimme       cx_u.cx_blk.blku_gimme
 519 #define blk_sub         cx_u.cx_blk.blk_u.blku_sub
 520 #define blk_eval        cx_u.cx_blk.blk_u.blku_eval
 521 #define blk_loop        cx_u.cx_blk.blk_u.blku_loop
 522 #define blk_givwhen     cx_u.cx_blk.blk_u.blku_givwhen
 523
 524 /* Enter a block. */
 525 #define PUSHBLOCK(cx,t,sp) CXINC, cx = &cxstack[cxstack_ix],            \
 526         cx->cx_type             = t,                                    \
 527         cx->blk_oldsp           = sp - PL_stack_base,                   \
 528         cx->blk_oldcop          = PL_curcop,                            \
 529         cx->blk_oldmarksp       = PL_markstack_ptr - PL_markstack,      \
 530         cx->blk_oldscopesp      = PL_scopestack_ix,                     \
 531         cx->blk_oldpm           = PL_curpm,                             \
 532         cx->blk_gimme           = (U8)gimme;                            \
 533         DEBUG_l( PerlIO_printf(Perl_debug_log, "Entering block %ld, type %s\n", \
 534                     (long)cxstack_ix, PL_block_type[CxTYPE(cx)]); )
 535
 536 /* Exit a block (RETURN and LAST). */
 537 #define POPBLOCK(cx,pm) cx = &cxstack[cxstack_ix--],                    \
 538         newsp            = PL_stack_base + cx->blk_oldsp,               \
 539         PL_curcop        = cx->blk_oldcop,                              \
 540         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
 541         PL_scopestack_ix = cx->blk_oldscopesp,                          \
 542         pm               = cx->blk_oldpm,                               \
 543         gimme            = cx->blk_gimme;                               \
 544         DEBUG_SCOPE("POPBLOCK");                                        \
 545         DEBUG_l( PerlIO_printf(Perl_debug_log, "Leaving block %ld, type %s\n",          \
 546                     (long)cxstack_ix+1,PL_block_type[CxTYPE(cx)]); )
 547
 548 /* Continue a block elsewhere (NEXT and REDO). */
 549 #define TOPBLOCK(cx) cx  = &cxstack[cxstack_ix],                        \
 550         PL_stack_sp      = PL_stack_base + cx->blk_oldsp,               \
 551         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
 552         PL_scopestack_ix = cx->blk_oldscopesp,                          \
 553         PL_curpm         = cx->blk_oldpm;                               \
 554         DEBUG_SCOPE("TOPBLOCK");
 555
 556 /* substitution context */
 557 struct subst {
 558     U16         sbu_type;       /* what kind of context this is */
 559     bool        sbu_once;
 560     bool        sbu_rxtainted;
 561     I32         sbu_iters;
 562     I32         sbu_maxiters;
 563     I32         sbu_rflags;
 564     I32         sbu_oldsave;
 565     char *      sbu_orig;
 566     SV *        sbu_dstr;
 567     SV *        sbu_targ;
 568     char *      sbu_s;
 569     char *      sbu_m;
 570     char *      sbu_strend;
 571     void *      sbu_rxres;
 572     REGEXP *    sbu_rx;
 573 };
 574 #define sb_iters        cx_u.cx_subst.sbu_iters
 575 #define sb_maxiters     cx_u.cx_subst.sbu_maxiters
 576 #define sb_rflags       cx_u.cx_subst.sbu_rflags
 577 #define sb_oldsave      cx_u.cx_subst.sbu_oldsave
 578 #define sb_once         cx_u.cx_subst.sbu_once
 579 #define sb_rxtainted    cx_u.cx_subst.sbu_rxtainted
 580 #define sb_orig         cx_u.cx_subst.sbu_orig
 581 #define sb_dstr         cx_u.cx_subst.sbu_dstr
 582 #define sb_targ         cx_u.cx_subst.sbu_targ
 583 #define sb_s            cx_u.cx_subst.sbu_s
 584 #define sb_m            cx_u.cx_subst.sbu_m
 585 #define sb_strend       cx_u.cx_subst.sbu_strend
 586 #define sb_rxres        cx_u.cx_subst.sbu_rxres
 587 #define sb_rx           cx_u.cx_subst.sbu_rx
 588
 589 #define PUSHSUBST(cx) CXINC, cx = &cxstack[cxstack_ix],                 \
 590         cx->sb_iters            = iters,                                \
 591         cx->sb_maxiters         = maxiters,                             \
 592         cx->sb_rflags           = r_flags,                              \
 593         cx->sb_oldsave          = oldsave,                              \
 594         cx->sb_once             = once,                                 \
 595         cx->sb_rxtainted        = rxtainted,                            \
 596         cx->sb_orig             = orig,                                 \
 597         cx->sb_dstr             = dstr,                                 \
 598         cx->sb_targ             = targ,                                 \
 599         cx->sb_s                = s,                                    \
 600         cx->sb_m                = m,                                    \
 601         cx->sb_strend           = strend,                               \
 602         cx->sb_rxres            = NULL,                                 \
 603         cx->sb_rx               = rx,                                   \
 604         cx->cx_type             = CXt_SUBST;                            \
 605         rxres_save(&cx->sb_rxres, rx);                                  \
 606         (void)ReREFCNT_inc(rx)
 607
 608 #define POPSUBST(cx) cx = &cxstack[cxstack_ix--];                       \
 609         rxres_free(&cx->sb_rxres);                                      \
 610         ReREFCNT_dec(cx->sb_rx)
 611
 612 struct context {
 613     union {
 614         struct block    cx_blk;
 615         struct subst    cx_subst;
 616     } cx_u;
 617 };
 618 #define cx_type cx_u.cx_subst.sbu_type
 619
 620 #define CXTYPEMASK      0xff
 621 #define CXt_NULL        0
 622 #define CXt_SUB         1
 623 #define CXt_EVAL        2
 624 #define CXt_LOOP        3
 625 #define CXt_SUBST       4
 626 #define CXt_BLOCK       5
 627 #define CXt_FORMAT      6
 628 #define CXt_GIVEN       7
 629 #define CXt_WHEN        8
 630
 631 /* private flags for CXt_SUB and CXt_NULL */
 632 #define CXp_MULTICALL   0x00000400      /* part of a multicall (so don't
 633                                            tear down context on exit). */
 634
 635 /* private flags for CXt_EVAL */
 636 #define CXp_REAL        0x00000100      /* truly eval'', not a lookalike */
 637 #define CXp_TRYBLOCK    0x00000200      /* eval{}, not eval'' or similar */
 638
 639 /* private flags for CXt_LOOP */
 640 #define CXp_FOREACH     0x00000200      /* a foreach loop */
 641 #define CXp_FOR_DEF     0x00000400      /* foreach using $_ */
 642 #ifdef USE_ITHREADS
 643 #  define CXp_PADVAR    0x00000100      /* itervar lives on pad, iterdata
 644                                            has pad offset; if not set,
 645                                            iterdata holds GV* */
 646 #  define CxPADLOOP(c)  (((c)->cx_type & (CXt_LOOP|CXp_PADVAR))         \
 647                          == (CXt_LOOP|CXp_PADVAR))
 648 #endif
 649
 650 #define CxTYPE(c)       ((c)->cx_type & CXTYPEMASK)
 651 #define CxMULTICALL(c)  (((c)->cx_type & CXp_MULTICALL)                 \
 652                          == CXp_MULTICALL)
 653 #define CxREALEVAL(c)   (((c)->cx_type & (CXt_EVAL|CXp_REAL))           \
 654                          == (CXt_EVAL|CXp_REAL))
 655 #define CxTRYBLOCK(c)   (((c)->cx_type & (CXt_EVAL|CXp_TRYBLOCK))       \
 656                          == (CXt_EVAL|CXp_TRYBLOCK))
 657 #define CxFOREACH(c)    (((c)->cx_type & (CXt_LOOP|CXp_FOREACH))        \
 658                          == (CXt_LOOP|CXp_FOREACH))
 659 #define CxFOREACHDEF(c) (((c)->cx_type & (CXt_LOOP|CXp_FOREACH|CXp_FOR_DEF))\
 660                          == (CXt_LOOP|CXp_FOREACH|CXp_FOR_DEF))
 661
 662 #define CXINC (cxstack_ix < cxstack_max ? ++cxstack_ix : (cxstack_ix = cxinc()))
 663
 664 /*
 665 =head1 "Gimme" Values
 666 */
 667
 668 /*
 669 =for apidoc AmU||G_SCALAR
 670 Used to indicate scalar context.  See C<GIMME_V>, C<GIMME>, and
 671 L<perlcall>.
 672
 673 =for apidoc AmU||G_ARRAY
 674 Used to indicate list context.  See C<GIMME_V>, C<GIMME> and
 675 L<perlcall>.
 676
 677 =for apidoc AmU||G_VOID
 678 Used to indicate void context.  See C<GIMME_V> and L<perlcall>.
 679
 680 =for apidoc AmU||G_DISCARD
 681 Indicates that arguments returned from a callback should be discarded.  See
 682 L<perlcall>.
 683
 684 =for apidoc AmU||G_EVAL
 685
 686 Used to force a Perl C<eval> wrapper around a callback.  See
 687 L<perlcall>.
 688
 689 =for apidoc AmU||G_NOARGS
 690
 691 Indicates that no arguments are being sent to a callback.  See
 692 L<perlcall>.
 693
 694 =cut
 695 */
 696
 697 #define G_SCALAR        0
 698 #define G_ARRAY         1
 699 #define G_VOID          128     /* skip this bit when adding flags below */
 700
 701 /* extra flags for Perl_call_* routines */
 702 #define G_DISCARD       2       /* Call FREETMPS. */
 703 #define G_EVAL          4       /* Assume eval {} around subroutine call. */
 704 #define G_NOARGS        8       /* Don't construct a @_ array. */
 705 #define G_KEEPERR      16       /* Append errors to $@, don't overwrite it */
 706 #define G_NODEBUG      32       /* Disable debugging at toplevel.  */
 707 #define G_METHOD       64       /* Calling method. */
 708 #define G_FAKINGEVAL  256       /* Faking en eval context for call_sv or
 709                                    fold_constants. */
 710
 711 /* flag bits for PL_in_eval */
 712 #define EVAL_NULL       0       /* not in an eval */
 713 #define EVAL_INEVAL     1       /* some enclosing scope is an eval */
 714 #define EVAL_WARNONLY   2       /* used by yywarn() when calling yyerror() */
 715 #define EVAL_KEEPERR    4       /* set by Perl_call_sv if G_KEEPERR */
 716 #define EVAL_INREQUIRE  8       /* The code is being required. */
 717
 718 /* Support for switching (stack and block) contexts.
 719  * This ensures magic doesn't invalidate local stack and cx pointers.
 720  */
 721
 722 #define PERLSI_UNKNOWN          -1
 723 #define PERLSI_UNDEF            0
 724 #define PERLSI_MAIN             1
 725 #define PERLSI_MAGIC            2
 726 #define PERLSI_SORT             3
 727 #define PERLSI_SIGNAL           4
 728 #define PERLSI_OVERLOAD         5
 729 #define PERLSI_DESTROY          6
 730 #define PERLSI_WARNHOOK         7
 731 #define PERLSI_DIEHOOK          8
 732 #define PERLSI_REQUIRE          9
 733
 734 struct stackinfo {
 735     AV *                si_stack;       /* stack for current runlevel */
 736     PERL_CONTEXT *      si_cxstack;     /* context stack for runlevel */
 737     I32                 si_cxix;        /* current context index */
 738     I32                 si_cxmax;       /* maximum allocated index */
 739     I32                 si_type;        /* type of runlevel */
 740     struct stackinfo *  si_prev;
 741     struct stackinfo *  si_next;
 742     I32                 si_markoff;     /* offset where markstack begins for us.
 743                                          * currently used only with DEBUGGING,
 744                                          * but not #ifdef-ed for bincompat */
 745 };
 746
 747 typedef struct stackinfo PERL_SI;
 748
 749 #define cxstack         (PL_curstackinfo->si_cxstack)
 750 #define cxstack_ix      (PL_curstackinfo->si_cxix)
 751 #define cxstack_max     (PL_curstackinfo->si_cxmax)
 752
 753 #ifdef DEBUGGING
 754 #  define       SET_MARK_OFFSET \
 755     PL_curstackinfo->si_markoff = PL_markstack_ptr - PL_markstack
 756 #else
 757 #  define       SET_MARK_OFFSET NOOP
 758 #endif
 759
 760 #define PUSHSTACKi(type) \
 761     STMT_START {                                                        \
 762         PERL_SI *next = PL_curstackinfo->si_next;                       \
 763         if (!next) {                                                    \
 764             next = new_stackinfo(32, 2048/sizeof(PERL_CONTEXT) - 1);    \
 765             next->si_prev = PL_curstackinfo;                            \
 766             PL_curstackinfo->si_next = next;                            \
 767         }                                                               \
 768         next->si_type = type;                                           \
 769         next->si_cxix = -1;                                             \
 770         AvFILLp(next->si_stack) = 0;                                    \
 771         SWITCHSTACK(PL_curstack,next->si_stack);                        \
 772         PL_curstackinfo = next;                                         \
 773         SET_MARK_OFFSET;                                                \
 774     } STMT_END
 775
 776 #define PUSHSTACK PUSHSTACKi(PERLSI_UNKNOWN)
 777
 778 /* POPSTACK works with PL_stack_sp, so it may need to be bracketed by
 779  * PUTBACK/SPAGAIN to flush/refresh any local SP that may be active */
 780 #define POPSTACK \
 781     STMT_START {                                                        \
 782         dSP;                                                            \
 783         PERL_SI * const prev = PL_curstackinfo->si_prev;                \
 784         if (!prev) {                                                    \
 785             PerlIO_printf(Perl_error_log, "panic: POPSTACK\n");         \
 786             my_exit(1);                                                 \
 787         }                                                               \
 788         SWITCHSTACK(PL_curstack,prev->si_stack);                        \
 789         /* don't free prev here, free them all at the END{} */          \
 790         PL_curstackinfo = prev;                                         \
 791     } STMT_END
 792
 793 #define POPSTACK_TO(s) \
 794     STMT_START {                                                        \
 795         while (PL_curstack != s) {                                      \
 796             dounwind(-1);                                               \
 797             POPSTACK;                                                   \
 798         }                                                               \
 799     } STMT_END
 800
 801 #define IN_PERL_COMPILETIME     (PL_curcop == &PL_compiling)
 802 #define IN_PERL_RUNTIME         (PL_curcop != &PL_compiling)
 803
 804 /*
 805 =head1 Multicall Functions
 806
 807 =for apidoc Ams||dMULTICALL
 808 Declare local variables for a multicall. See L<perlcall/Lightweight Callbacks>.
 809
 810 =for apidoc Ams||PUSH_MULTICALL
 811 Opening bracket for a lightweight callback.
 812 See L<perlcall/Lightweight Callbacks>.
 813
 814 =for apidoc Ams||MULTICALL
 815 Make a lightweight callback. See L<perlcall/Lightweight Callbacks>.
 816
 817 =for apidoc Ams||POP_MULTICALL
 818 Closing bracket for a lightweight callback.
 819 See L<perlcall/Lightweight Callbacks>.
 820
 821 =cut
 822 */
 823
 824 #define dMULTICALL \
 825     SV **newsp;                 /* set by POPBLOCK */                   \
 826     PERL_CONTEXT *cx;                                                   \
 827     CV *multicall_cv;                                                   \
 828     OP *multicall_cop;                                                  \
 829     bool multicall_oldcatch;                                            \
 830     U8 hasargs = 0              /* used by PUSHSUB */
 831
 832 #define PUSH_MULTICALL(the_cv) \
 833     STMT_START {                                                        \
 834         CV * const _nOnclAshIngNamE_ = the_cv;                          \
 835         CV * const cv = _nOnclAshIngNamE_;                              \
 836         AV * const padlist = CvPADLIST(cv);                             \
 837         ENTER;                                                          \
 838         multicall_oldcatch = CATCH_GET;                                 \
 839         SAVETMPS; SAVEVPTR(PL_op);                                      \
 840         CATCH_SET(TRUE);                                                \
 841         PUSHBLOCK(cx, CXt_SUB|CXp_MULTICALL, PL_stack_sp);              \
 842         PUSHSUB(cx);                                                    \
 843         if (++CvDEPTH(cv) >= 2) {                                       \
 844             PERL_STACK_OVERFLOW_CHECK();                                \
 845             Perl_pad_push(aTHX_ padlist, CvDEPTH(cv));                  \
 846         }                                                               \
 847         SAVECOMPPAD();                                                  \
 848         PAD_SET_CUR_NOSAVE(padlist, CvDEPTH(cv));                       \
 849         multicall_cv = cv;                                              \
 850         multicall_cop = CvSTART(cv);                                    \
 851     } STMT_END
 852
 853 #define MULTICALL \
 854     STMT_START {                                                        \
 855         PL_op = multicall_cop;                                          \
 856         CALLRUNOPS(aTHX);                                               \
 857     } STMT_END
 858
 859 #define POP_MULTICALL \
 860     STMT_START {                                                        \
 861         LEAVESUB(multicall_cv);                                         \
 862         CvDEPTH(multicall_cv)--;                                        \
 863         POPBLOCK(cx,PL_curpm);                                          \
 864         CATCH_SET(multicall_oldcatch);                                  \
 865         LEAVE;                                                          \
 866     } STMT_END
 867
 868 /*
 869  * Local variables:
 870  * c-indentation-style: bsd
 871  * c-basic-offset: 4
 872  * indent-tabs-mode: t
 873  * End:
 874  *
 875  * ex: set ts=8 sts=4 sw=4 noet:
 876  */