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