cop.h

   1 /*    cop.h
   2  *
   3  *    Copyright (c) 1991-2000, Larry Wall
   4  *
   5  *    You may distribute under the terms of either the GNU General Public
   6  *    License or the Artistic License, as specified in the README file.
   7  *
   8  */
   9
  10 struct cop {
  11     BASEOP
  12     char *      cop_label;      /* label for this construct */
  13 #ifdef USE_ITHREADS
  14     char *      cop_stashpv;    /* package line was compiled in */
  15     char *      cop_file;       /* file name the following line # is from */
  16 #else
  17     HV *        cop_stash;      /* package line was compiled in */
  18     GV *        cop_filegv;     /* file the following line # is from */
  19 #endif
  20     U32         cop_seq;        /* parse sequence number */
  21     I32         cop_arybase;    /* array base this line was compiled with */
  22     line_t      cop_line;       /* line # of this command */
  23     SV *        cop_warnings;   /* lexical warnings bitmask */
  24 };
  25
  26 #define Nullcop Null(COP*)
  27
  28 #ifdef USE_ITHREADS
  29 #  define CopFILE(c)            ((c)->cop_file)
  30 #  define CopFILEGV(c)          (CopFILE(c) \
  31                                  ? gv_fetchfile(CopFILE(c)) : Nullgv)
  32 #  define CopFILE_set(c,pv)     ((c)->cop_file = savepv(pv))
  33 #  define CopFILESV(c)          (CopFILE(c) \
  34                                  ? GvSV(gv_fetchfile(CopFILE(c))) : Nullsv)
  35 #  define CopFILEAV(c)          (CopFILE(c) \
  36                                  ? GvAV(gv_fetchfile(CopFILE(c))) : Nullav)
  37 #  define CopSTASHPV(c)         ((c)->cop_stashpv)
  38 #  define CopSTASHPV_set(c,pv)  ((c)->cop_stashpv = ((pv) ? savepv(pv) : Nullch))
  39 #  define CopSTASH(c)           (CopSTASHPV(c) \
  40                                  ? gv_stashpv(CopSTASHPV(c),GV_ADD) : Nullhv)
  41 #  define CopSTASH_set(c,hv)    CopSTASHPV_set(c, (hv) ? HvNAME(hv) : Nullch)
  42 #  define CopSTASH_eq(c,hv)     ((hv)                                   \
  43                                  && (CopSTASHPV(c) == HvNAME(hv)        \
  44                                      || (CopSTASHPV(c) && HvNAME(hv)    \
  45                                          && strEQ(CopSTASHPV(c), HvNAME(hv)))))
  46 #else
  47 #  define CopFILEGV(c)          ((c)->cop_filegv)
  48 #  define CopFILEGV_set(c,gv)   ((c)->cop_filegv = (GV*)SvREFCNT_inc(gv))
  49 #  define CopFILE_set(c,pv)     CopFILEGV_set((c), gv_fetchfile(pv))
  50 #  define CopFILESV(c)          (CopFILEGV(c) ? GvSV(CopFILEGV(c)) : Nullsv)
  51 #  define CopFILEAV(c)          (CopFILEGV(c) ? GvAV(CopFILEGV(c)) : Nullav)
  52 #  define CopFILE(c)            (CopFILESV(c) ? SvPVX(CopFILESV(c)) : Nullch)
  53 #  define CopSTASH(c)           ((c)->cop_stash)
  54 #  define CopSTASH_set(c,hv)    ((c)->cop_stash = (hv))
  55 #  define CopSTASHPV(c)         (CopSTASH(c) ? HvNAME(CopSTASH(c)) : Nullch)
  56    /* cop_stash is not refcounted */
  57 #  define CopSTASHPV_set(c,pv)  CopSTASH_set((c), gv_stashpv(pv,GV_ADD))
  58 #  define CopSTASH_eq(c,hv)     (CopSTASH(c) == (hv))
  59 #endif /* USE_ITHREADS */
  60
  61 #define CopSTASH_ne(c,hv)       (!CopSTASH_eq(c,hv))
  62 #define CopLINE(c)              ((c)->cop_line)
  63 #define CopLINE_inc(c)          (++CopLINE(c))
  64 #define CopLINE_dec(c)          (--CopLINE(c))
  65 #define CopLINE_set(c,l)        (CopLINE(c) = (l))
  66
  67 /*
  68  * Here we have some enormously heavy (or at least ponderous) wizardry.
  69  */
  70
  71 /* subroutine context */
  72 struct block_sub {
  73     CV *        cv;
  74     GV *        gv;
  75     GV *        dfoutgv;
  76 #ifndef USE_THREADS
  77     AV *        savearray;
  78 #endif /* USE_THREADS */
  79     AV *        argarray;
  80     U16         olddepth;
  81     U8          hasargs;
  82     U8          lval;           /* XXX merge lval and hasargs? */
  83     SV **       oldcurpad;
  84 };
  85
  86 #define PUSHSUB(cx)                                                     \
  87         cx->blk_sub.cv = cv;                                            \
  88         cx->blk_sub.olddepth = CvDEPTH(cv);                             \
  89         cx->blk_sub.hasargs = hasargs;                                  \
  90         cx->blk_sub.lval = PL_op->op_private &                          \
  91                               (OPpLVAL_INTRO|OPpENTERSUB_INARGS);
  92
  93 #define PUSHFORMAT(cx)                                                  \
  94         cx->blk_sub.cv = cv;                                            \
  95         cx->blk_sub.gv = gv;                                            \
  96         cx->blk_sub.hasargs = 0;                                        \
  97         cx->blk_sub.dfoutgv = PL_defoutgv;                              \
  98         (void)SvREFCNT_inc(cx->blk_sub.dfoutgv)
  99
 100 #ifdef USE_THREADS
 101 #  define POP_SAVEARRAY() NOOP
 102 #else
 103 #  define POP_SAVEARRAY()                                               \
 104     STMT_START {                                                        \
 105         SvREFCNT_dec(GvAV(PL_defgv));                                   \
 106         GvAV(PL_defgv) = cx->blk_sub.savearray;                         \
 107     } STMT_END
 108 #endif /* USE_THREADS */
 109
 110 /* junk in @_ spells trouble when cloning CVs and in pp_caller(), so don't
 111  * leave any (a fast av_clear(ary), basically) */
 112 #define CLEAR_ARGARRAY(ary) \
 113     STMT_START {                                                        \
 114         AvMAX(ary) += AvARRAY(ary) - AvALLOC(ary);                      \
 115         SvPVX(ary) = (char*)AvALLOC(ary);                               \
 116         AvFILLp(ary) = -1;                                              \
 117     } STMT_END
 118
 119 #define POPSUB(cx,sv)                                                   \
 120     STMT_START {                                                        \
 121         if (cx->blk_sub.hasargs) {                                      \
 122             POP_SAVEARRAY();                                            \
 123             /* abandon @_ if it got reified */                          \
 124             if (AvREAL(cx->blk_sub.argarray)) {                         \
 125                 SSize_t fill = AvFILLp(cx->blk_sub.argarray);           \
 126                 SvREFCNT_dec(cx->blk_sub.argarray);                     \
 127                 cx->blk_sub.argarray = newAV();                         \
 128                 av_extend(cx->blk_sub.argarray, fill);                  \
 129                 AvFLAGS(cx->blk_sub.argarray) = AVf_REIFY;              \
 130                 cx->blk_sub.oldcurpad[0] = (SV*)cx->blk_sub.argarray;   \
 131             }                                                           \
 132             else {                                                      \
 133                 CLEAR_ARGARRAY(cx->blk_sub.argarray);                   \
 134             }                                                           \
 135         }                                                               \
 136         sv = (SV*)cx->blk_sub.cv;                                       \
 137         if (sv && (CvDEPTH((CV*)sv) = cx->blk_sub.olddepth))            \
 138             sv = Nullsv;                                                \
 139     } STMT_END
 140
 141 #define LEAVESUB(sv)                                                    \
 142     STMT_START {                                                        \
 143         if (sv)                                                         \
 144             SvREFCNT_dec(sv);                                           \
 145     } STMT_END
 146
 147 #define POPFORMAT(cx)                                                   \
 148         setdefout(cx->blk_sub.dfoutgv);                                 \
 149         SvREFCNT_dec(cx->blk_sub.dfoutgv);
 150
 151 /* eval context */
 152 struct block_eval {
 153     I32         old_in_eval;
 154     I32         old_op_type;
 155     SV *        old_namesv;
 156     OP *        old_eval_root;
 157     SV *        cur_text;
 158 };
 159
 160 #define PUSHEVAL(cx,n,fgv)                                              \
 161     STMT_START {                                                        \
 162         cx->blk_eval.old_in_eval = PL_in_eval;                          \
 163         cx->blk_eval.old_op_type = PL_op->op_type;                      \
 164         cx->blk_eval.old_namesv = (n ? newSVpv(n,0) : Nullsv);          \
 165         cx->blk_eval.old_eval_root = PL_eval_root;                      \
 166         cx->blk_eval.cur_text = PL_linestr;                             \
 167     } STMT_END
 168
 169 #define POPEVAL(cx)                                                     \
 170     STMT_START {                                                        \
 171         PL_in_eval = cx->blk_eval.old_in_eval;                          \
 172         optype = cx->blk_eval.old_op_type;                              \
 173         PL_eval_root = cx->blk_eval.old_eval_root;                      \
 174         if (cx->blk_eval.old_namesv)                                    \
 175             sv_2mortal(cx->blk_eval.old_namesv);                        \
 176     } STMT_END
 177
 178 /* loop context */
 179 struct block_loop {
 180     char *      label;
 181     I32         resetsp;
 182     OP *        redo_op;
 183     OP *        next_op;
 184     OP *        last_op;
 185 #ifdef USE_ITHREADS
 186     void *      iterdata;
 187     SV **       oldcurpad;
 188 #else
 189     SV **       itervar;
 190 #endif
 191     SV *        itersave;
 192     SV *        iterlval;
 193     AV *        iterary;
 194     IV          iterix;
 195     IV          itermax;
 196 };
 197
 198 #ifdef USE_ITHREADS
 199 #  define CxITERVAR(c)                                                  \
 200         ((c)->blk_loop.iterdata                                         \
 201          ? (CxPADLOOP(cx)                                               \
 202             ? &((c)->blk_loop.oldcurpad)[(PADOFFSET)(c)->blk_loop.iterdata]     \
 203             : &GvSV((GV*)(c)->blk_loop.iterdata))                       \
 204          : (SV**)NULL)
 205 #  define CX_ITERDATA_SET(cx,idata)                                     \
 206         cx->blk_loop.oldcurpad = PL_curpad;                             \
 207         if ((cx->blk_loop.iterdata = (idata)))                          \
 208             cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));
 209 #else
 210 #  define CxITERVAR(c)          ((c)->blk_loop.itervar)
 211 #  define CX_ITERDATA_SET(cx,ivar)                                      \
 212         if ((cx->blk_loop.itervar = (SV**)(ivar)))                      \
 213             cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));
 214 #endif
 215
 216 #define PUSHLOOP(cx, dat, s)                                            \
 217         cx->blk_loop.label = PL_curcop->cop_label;                      \
 218         cx->blk_loop.resetsp = s - PL_stack_base;                       \
 219         cx->blk_loop.redo_op = cLOOP->op_redoop;                        \
 220         cx->blk_loop.next_op = cLOOP->op_nextop;                        \
 221         cx->blk_loop.last_op = cLOOP->op_lastop;                        \
 222         cx->blk_loop.iterlval = Nullsv;                                 \
 223         cx->blk_loop.iterary = Nullav;                                  \
 224         cx->blk_loop.iterix = -1;                                       \
 225         CX_ITERDATA_SET(cx,dat);
 226
 227 #define POPLOOP(cx)                                                     \
 228         SvREFCNT_dec(cx->blk_loop.iterlval);                            \
 229         if (CxITERVAR(cx)) {                                            \
 230             SV **s_v_p = CxITERVAR(cx);                                 \
 231             sv_2mortal(*s_v_p);                                         \
 232             *s_v_p = cx->blk_loop.itersave;                             \
 233         }                                                               \
 234         if (cx->blk_loop.iterary && cx->blk_loop.iterary != PL_curstack)\
 235             SvREFCNT_dec(cx->blk_loop.iterary);
 236
 237 /* context common to subroutines, evals and loops */
 238 struct block {
 239     I32         blku_oldsp;     /* stack pointer to copy stuff down to */
 240     COP *       blku_oldcop;    /* old curcop pointer */
 241     I32         blku_oldretsp;  /* return stack index */
 242     I32         blku_oldmarksp; /* mark stack index */
 243     I32         blku_oldscopesp;        /* scope stack index */
 244     PMOP *      blku_oldpm;     /* values of pattern match vars */
 245     U8          blku_gimme;     /* is this block running in list context? */
 246
 247     union {
 248         struct block_sub        blku_sub;
 249         struct block_eval       blku_eval;
 250         struct block_loop       blku_loop;
 251     } blk_u;
 252 };
 253 #define blk_oldsp       cx_u.cx_blk.blku_oldsp
 254 #define blk_oldcop      cx_u.cx_blk.blku_oldcop
 255 #define blk_oldretsp    cx_u.cx_blk.blku_oldretsp
 256 #define blk_oldmarksp   cx_u.cx_blk.blku_oldmarksp
 257 #define blk_oldscopesp  cx_u.cx_blk.blku_oldscopesp
 258 #define blk_oldpm       cx_u.cx_blk.blku_oldpm
 259 #define blk_gimme       cx_u.cx_blk.blku_gimme
 260 #define blk_sub         cx_u.cx_blk.blk_u.blku_sub
 261 #define blk_eval        cx_u.cx_blk.blk_u.blku_eval
 262 #define blk_loop        cx_u.cx_blk.blk_u.blku_loop
 263
 264 /* Enter a block. */
 265 #define PUSHBLOCK(cx,t,sp) CXINC, cx = &cxstack[cxstack_ix],            \
 266         cx->cx_type             = t,                                    \
 267         cx->blk_oldsp           = sp - PL_stack_base,                   \
 268         cx->blk_oldcop          = PL_curcop,                            \
 269         cx->blk_oldmarksp       = PL_markstack_ptr - PL_markstack,      \
 270         cx->blk_oldscopesp      = PL_scopestack_ix,                     \
 271         cx->blk_oldretsp        = PL_retstack_ix,                       \
 272         cx->blk_oldpm           = PL_curpm,                             \
 273         cx->blk_gimme           = gimme;                                \
 274         DEBUG_l( PerlIO_printf(Perl_debug_log, "Entering block %ld, type %s\n", \
 275                     (long)cxstack_ix, PL_block_type[CxTYPE(cx)]); )
 276
 277 /* Exit a block (RETURN and LAST). */
 278 #define POPBLOCK(cx,pm) cx = &cxstack[cxstack_ix--],                    \
 279         newsp            = PL_stack_base + cx->blk_oldsp,               \
 280         PL_curcop        = cx->blk_oldcop,                              \
 281         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
 282         PL_scopestack_ix = cx->blk_oldscopesp,                          \
 283         PL_retstack_ix   = cx->blk_oldretsp,                            \
 284         pm               = cx->blk_oldpm,                               \
 285         gimme            = cx->blk_gimme;                               \
 286         DEBUG_l( PerlIO_printf(Perl_debug_log, "Leaving block %ld, type %s\n",          \
 287                     (long)cxstack_ix+1,PL_block_type[CxTYPE(cx)]); )
 288
 289 /* Continue a block elsewhere (NEXT and REDO). */
 290 #define TOPBLOCK(cx) cx  = &cxstack[cxstack_ix],                        \
 291         PL_stack_sp      = PL_stack_base + cx->blk_oldsp,               \
 292         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
 293         PL_scopestack_ix = cx->blk_oldscopesp,                          \
 294         PL_retstack_ix   = cx->blk_oldretsp,                            \
 295         PL_curpm         = cx->blk_oldpm
 296
 297 /* substitution context */
 298 struct subst {
 299     I32         sbu_iters;
 300     I32         sbu_maxiters;
 301     I32         sbu_rflags;
 302     I32         sbu_oldsave;
 303     bool        sbu_once;
 304     bool        sbu_rxtainted;
 305     char *      sbu_orig;
 306     SV *        sbu_dstr;
 307     SV *        sbu_targ;
 308     char *      sbu_s;
 309     char *      sbu_m;
 310     char *      sbu_strend;
 311     void *      sbu_rxres;
 312     REGEXP *    sbu_rx;
 313 };
 314 #define sb_iters        cx_u.cx_subst.sbu_iters
 315 #define sb_maxiters     cx_u.cx_subst.sbu_maxiters
 316 #define sb_rflags       cx_u.cx_subst.sbu_rflags
 317 #define sb_oldsave      cx_u.cx_subst.sbu_oldsave
 318 #define sb_once         cx_u.cx_subst.sbu_once
 319 #define sb_rxtainted    cx_u.cx_subst.sbu_rxtainted
 320 #define sb_orig         cx_u.cx_subst.sbu_orig
 321 #define sb_dstr         cx_u.cx_subst.sbu_dstr
 322 #define sb_targ         cx_u.cx_subst.sbu_targ
 323 #define sb_s            cx_u.cx_subst.sbu_s
 324 #define sb_m            cx_u.cx_subst.sbu_m
 325 #define sb_strend       cx_u.cx_subst.sbu_strend
 326 #define sb_rxres        cx_u.cx_subst.sbu_rxres
 327 #define sb_rx           cx_u.cx_subst.sbu_rx
 328
 329 #define PUSHSUBST(cx) CXINC, cx = &cxstack[cxstack_ix],                 \
 330         cx->sb_iters            = iters,                                \
 331         cx->sb_maxiters         = maxiters,                             \
 332         cx->sb_rflags           = r_flags,                              \
 333         cx->sb_oldsave          = oldsave,                              \
 334         cx->sb_once             = once,                                 \
 335         cx->sb_rxtainted        = rxtainted,                            \
 336         cx->sb_orig             = orig,                                 \
 337         cx->sb_dstr             = dstr,                                 \
 338         cx->sb_targ             = targ,                                 \
 339         cx->sb_s                = s,                                    \
 340         cx->sb_m                = m,                                    \
 341         cx->sb_strend           = strend,                               \
 342         cx->sb_rxres            = Null(void*),                          \
 343         cx->sb_rx               = rx,                                   \
 344         cx->cx_type             = CXt_SUBST;                            \
 345         rxres_save(&cx->sb_rxres, rx)
 346
 347 #define POPSUBST(cx) cx = &cxstack[cxstack_ix--];                       \
 348         rxres_free(&cx->sb_rxres)
 349
 350 struct context {
 351     U32         cx_type;        /* what kind of context this is */
 352     union {
 353         struct block    cx_blk;
 354         struct subst    cx_subst;
 355     } cx_u;
 356 };
 357
 358 #define CXTYPEMASK      0xff
 359 #define CXt_NULL        0
 360 #define CXt_SUB         1
 361 #define CXt_EVAL        2
 362 #define CXt_LOOP        3
 363 #define CXt_SUBST       4
 364 #define CXt_BLOCK       5
 365 #define CXt_FORMAT      6
 366
 367 /* private flags for CXt_EVAL */
 368 #define CXp_REAL        0x00000100      /* truly eval'', not a lookalike */
 369 #define CXp_TRYBLOCK    0x00000200      /* eval{}, not eval'' or similar */
 370
 371 #ifdef USE_ITHREADS
 372 /* private flags for CXt_LOOP */
 373 #  define CXp_PADVAR    0x00000100      /* itervar lives on pad, iterdata
 374                                            has pad offset; if not set,
 375                                            iterdata holds GV* */
 376 #  define CxPADLOOP(c)  (((c)->cx_type & (CXt_LOOP|CXp_PADVAR))         \
 377                          == (CXt_LOOP|CXp_PADVAR))
 378 #endif
 379
 380 #define CxTYPE(c)       ((c)->cx_type & CXTYPEMASK)
 381 #define CxREALEVAL(c)   (((c)->cx_type & (CXt_EVAL|CXp_REAL))           \
 382                          == (CXt_EVAL|CXp_REAL))
 383 #define CxTRYBLOCK(c)   (((c)->cx_type & (CXt_EVAL|CXp_TRYBLOCK))       \
 384                          == (CXt_EVAL|CXp_TRYBLOCK))
 385
 386 #define CXINC (cxstack_ix < cxstack_max ? ++cxstack_ix : (cxstack_ix = cxinc()))
 387
 388 /* "gimme" values */
 389
 390 /*
 391 =for apidoc AmU||G_SCALAR
 392 Used to indicate scalar context.  See C<GIMME_V>, C<GIMME>, and
 393 L<perlcall>.
 394
 395 =for apidoc AmU||G_ARRAY
 396 Used to indicate list context.  See C<GIMME_V>, C<GIMME> and
 397 L<perlcall>.
 398
 399 =for apidoc AmU||G_VOID
 400 Used to indicate void context.  See C<GIMME_V> and L<perlcall>.
 401
 402 =for apidoc AmU||G_DISCARD
 403 Indicates that arguments returned from a callback should be discarded.  See
 404 L<perlcall>.
 405
 406 =for apidoc AmU||G_EVAL
 407
 408 Used to force a Perl C<eval> wrapper around a callback.  See
 409 L<perlcall>.
 410
 411 =for apidoc AmU||G_NOARGS
 412
 413 Indicates that no arguments are being sent to a callback.  See
 414 L<perlcall>.
 415
 416 =cut
 417 */
 418
 419 #define G_SCALAR        0
 420 #define G_ARRAY         1
 421 #define G_VOID          128     /* skip this bit when adding flags below */
 422
 423 /* extra flags for Perl_call_* routines */
 424 #define G_DISCARD       2       /* Call FREETMPS. */
 425 #define G_EVAL          4       /* Assume eval {} around subroutine call. */
 426 #define G_NOARGS        8       /* Don't construct a @_ array. */
 427 #define G_KEEPERR      16       /* Append errors to $@, don't overwrite it */
 428 #define G_NODEBUG      32       /* Disable debugging at toplevel.  */
 429 #define G_METHOD       64       /* Calling method. */
 430
 431 /* flag bits for PL_in_eval */
 432 #define EVAL_NULL       0       /* not in an eval */
 433 #define EVAL_INEVAL     1       /* some enclosing scope is an eval */
 434 #define EVAL_WARNONLY   2       /* used by yywarn() when calling yyerror() */
 435 #define EVAL_KEEPERR    4       /* set by Perl_call_sv if G_KEEPERR */
 436
 437 /* Support for switching (stack and block) contexts.
 438  * This ensures magic doesn't invalidate local stack and cx pointers.
 439  */
 440
 441 #define PERLSI_UNKNOWN          -1
 442 #define PERLSI_UNDEF            0
 443 #define PERLSI_MAIN             1
 444 #define PERLSI_MAGIC            2
 445 #define PERLSI_SORT             3
 446 #define PERLSI_SIGNAL           4
 447 #define PERLSI_OVERLOAD         5
 448 #define PERLSI_DESTROY          6
 449 #define PERLSI_WARNHOOK         7
 450 #define PERLSI_DIEHOOK          8
 451 #define PERLSI_REQUIRE          9
 452
 453 struct stackinfo {
 454     AV *                si_stack;       /* stack for current runlevel */
 455     PERL_CONTEXT *      si_cxstack;     /* context stack for runlevel */
 456     I32                 si_cxix;        /* current context index */
 457     I32                 si_cxmax;       /* maximum allocated index */
 458     I32                 si_type;        /* type of runlevel */
 459     struct stackinfo *  si_prev;
 460     struct stackinfo *  si_next;
 461     I32                 si_markoff;     /* offset where markstack begins for us.
 462                                          * currently used only with DEBUGGING,
 463                                          * but not #ifdef-ed for bincompat */
 464 };
 465
 466 typedef struct stackinfo PERL_SI;
 467
 468 #define cxstack         (PL_curstackinfo->si_cxstack)
 469 #define cxstack_ix      (PL_curstackinfo->si_cxix)
 470 #define cxstack_max     (PL_curstackinfo->si_cxmax)
 471
 472 #ifdef DEBUGGING
 473 #  define       SET_MARK_OFFSET \
 474     PL_curstackinfo->si_markoff = PL_markstack_ptr - PL_markstack
 475 #else
 476 #  define       SET_MARK_OFFSET NOOP
 477 #endif
 478
 479 #define PUSHSTACKi(type) \
 480     STMT_START {                                                        \
 481         PERL_SI *next = PL_curstackinfo->si_next;                       \
 482         if (!next) {                                                    \
 483             next = new_stackinfo(32, 2048/sizeof(PERL_CONTEXT) - 1);    \
 484             next->si_prev = PL_curstackinfo;                            \
 485             PL_curstackinfo->si_next = next;                            \
 486         }                                                               \
 487         next->si_type = type;                                           \
 488         next->si_cxix = -1;                                             \
 489         AvFILLp(next->si_stack) = 0;                                    \
 490         SWITCHSTACK(PL_curstack,next->si_stack);                        \
 491         PL_curstackinfo = next;                                         \
 492         SET_MARK_OFFSET;                                                \
 493     } STMT_END
 494
 495 #define PUSHSTACK PUSHSTACKi(PERLSI_UNKNOWN)
 496
 497 /* POPSTACK works with PL_stack_sp, so it may need to be bracketed by
 498  * PUTBACK/SPAGAIN to flush/refresh any local SP that may be active */
 499 #define POPSTACK \
 500     STMT_START {                                                        \
 501         djSP;                                                           \
 502         PERL_SI *prev = PL_curstackinfo->si_prev;                       \
 503         if (!prev) {                                                    \
 504             PerlIO_printf(Perl_error_log, "panic: POPSTACK\n");         \
 505             my_exit(1);                                                 \
 506         }                                                               \
 507         SWITCHSTACK(PL_curstack,prev->si_stack);                        \
 508         /* don't free prev here, free them all at the END{} */          \
 509         PL_curstackinfo = prev;                                         \
 510     } STMT_END
 511
 512 #define POPSTACK_TO(s) \
 513     STMT_START {                                                        \
 514         while (PL_curstack != s) {                                      \
 515             dounwind(-1);                                               \
 516             POPSTACK;                                                   \
 517         }                                                               \
 518     } STMT_END