cop.h

   1 /*    cop.h
   2  *
   3  *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
   4  *    2000, 2001, 2002, 2003, 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 struct cop {
  17     BASEOP
  18     char *      cop_label;      /* label for this construct */
  19 #ifdef USE_ITHREADS
  20     char *      cop_stashpv;    /* package line was compiled in */
  21     char *      cop_file;       /* file name the following line # is from */
  22 #else
  23     HV *        cop_stash;      /* package line was compiled in */
  24     GV *        cop_filegv;     /* file the following line # is from */
  25 #endif
  26     U32         cop_seq;        /* parse sequence number */
  27     I32         cop_arybase;    /* array base this line was compiled with */
  28     line_t      cop_line;       /* line # of this command */
  29     SV *        cop_warnings;   /* lexical warnings bitmask */
  30     SV *        cop_io;         /* lexical IO defaults */
  31 };
  32
  33 #define Nullcop Null(COP*)
  34
  35 #ifdef USE_ITHREADS
  36 #  define CopFILE(c)            ((c)->cop_file)
  37 #  define CopFILEGV(c)          (CopFILE(c) \
  38                                  ? gv_fetchfile(CopFILE(c)) : Nullgv)
  39
  40  #ifdef NETWARE
  41   #define CopFILE_set(c,pv)     ((c)->cop_file = savepv(pv))
  42  #else
  43   #define CopFILE_set(c,pv)     ((c)->cop_file = savesharedpv(pv))
  44  #endif
  45
  46 #  define CopFILESV(c)          (CopFILE(c) \
  47                                  ? GvSV(gv_fetchfile(CopFILE(c))) : Nullsv)
  48 #  define CopFILEAV(c)          (CopFILE(c) \
  49                                  ? GvAV(gv_fetchfile(CopFILE(c))) : Nullav)
  50 #  define CopSTASHPV(c)         ((c)->cop_stashpv)
  51
  52   #ifdef NETWARE
  53     #define CopSTASHPV_set(c,pv)        ((c)->cop_stashpv = ((pv) ? savepv(pv) : Nullch))
  54   #else
  55     #define CopSTASHPV_set(c,pv)        ((c)->cop_stashpv = savesharedpv(pv))
  56   #endif
  57
  58 #  define CopSTASH(c)           (CopSTASHPV(c) \
  59                                  ? gv_stashpv(CopSTASHPV(c),GV_ADD) : Nullhv)
  60 #  define CopSTASH_set(c,hv)    CopSTASHPV_set(c, (hv) ? HvNAME(hv) : Nullch)
  61 #  define CopSTASH_eq(c,hv)     ((hv)                                   \
  62                                  && (CopSTASHPV(c) == HvNAME(hv)        \
  63                                      || (CopSTASHPV(c) && HvNAME(hv)    \
  64                                          && strEQ(CopSTASHPV(c), HvNAME(hv)))))
  65   #ifdef NETWARE
  66     #define CopSTASH_free(c) SAVECOPSTASH_FREE(c)
  67   #else
  68     #define CopSTASH_free(c)    PerlMemShared_free(CopSTASHPV(c))
  69   #endif
  70
  71   #ifdef NETWARE
  72     #define CopFILE_free(c) SAVECOPFILE_FREE(c)
  73   #else
  74     #define CopFILE_free(c)     (PerlMemShared_free(CopFILE(c)),(CopFILE(c) = Nullch))
  75   #endif
  76 #else
  77 #  define CopFILEGV(c)          ((c)->cop_filegv)
  78 #  define CopFILEGV_set(c,gv)   ((c)->cop_filegv = (GV*)SvREFCNT_inc(gv))
  79 #  define CopFILE_set(c,pv)     CopFILEGV_set((c), gv_fetchfile(pv))
  80 #  define CopFILESV(c)          (CopFILEGV(c) ? GvSV(CopFILEGV(c)) : Nullsv)
  81 #  define CopFILEAV(c)          (CopFILEGV(c) ? GvAV(CopFILEGV(c)) : Nullav)
  82 #  define CopFILE(c)            (CopFILESV(c) ? SvPVX(CopFILESV(c)) : Nullch)
  83 #  define CopSTASH(c)           ((c)->cop_stash)
  84 #  define CopSTASH_set(c,hv)    ((c)->cop_stash = (hv))
  85 #  define CopSTASHPV(c)         (CopSTASH(c) ? HvNAME(CopSTASH(c)) : Nullch)
  86    /* cop_stash is not refcounted */
  87 #  define CopSTASHPV_set(c,pv)  CopSTASH_set((c), gv_stashpv(pv,GV_ADD))
  88 #  define CopSTASH_eq(c,hv)     (CopSTASH(c) == (hv))
  89 #  define CopSTASH_free(c)
  90 #  define CopFILE_free(c)       (SvREFCNT_dec(CopFILEGV(c)),(CopFILEGV(c) = Nullgv))
  91
  92 #endif /* USE_ITHREADS */
  93
  94 #define CopSTASH_ne(c,hv)       (!CopSTASH_eq(c,hv))
  95 #define CopLINE(c)              ((c)->cop_line)
  96 #define CopLINE_inc(c)          (++CopLINE(c))
  97 #define CopLINE_dec(c)          (--CopLINE(c))
  98 #define CopLINE_set(c,l)        (CopLINE(c) = (l))
  99
 100 /* OutCopFILE() is CopFILE for output (caller, die, warn, etc.) */
 101 #ifdef MACOS_TRADITIONAL
 102 #  define OutCopFILE(c) MacPerl_MPWFileName(CopFILE(c))
 103 #else
 104 #  define OutCopFILE(c) CopFILE(c)
 105 #endif
 106
 107 /*
 108  * Here we have some enormously heavy (or at least ponderous) wizardry.
 109  */
 110
 111 /* subroutine context */
 112 struct block_sub {
 113     CV *        cv;
 114     GV *        gv;
 115     GV *        dfoutgv;
 116     AV *        savearray;
 117     AV *        argarray;
 118     long        olddepth;
 119     U8          hasargs;
 120     U8          lval;           /* XXX merge lval and hasargs? */
 121     PAD         *oldcomppad;
 122 };
 123
 124 /* base for the next two macros. Don't use directly */
 125 #define PUSHSUB_BASE(cx)                                                \
 126         cx->blk_sub.cv = cv;                                            \
 127         cx->blk_sub.olddepth = CvDEPTH(cv);                             \
 128         cx->blk_sub.hasargs = hasargs;
 129
 130 #define PUSHSUB(cx)                                                     \
 131         PUSHSUB_BASE(cx)                                                \
 132         cx->blk_sub.lval = PL_op->op_private &                          \
 133                               (OPpLVAL_INTRO|OPpENTERSUB_INARGS);
 134
 135 /* variant for use by OP_DBSTATE, where op_private holds hint bits */
 136 #define PUSHSUB_DB(cx)                                                  \
 137         PUSHSUB_BASE(cx)                                                \
 138         cx->blk_sub.lval = 0;
 139
 140
 141 #define PUSHFORMAT(cx)                                                  \
 142         cx->blk_sub.cv = cv;                                            \
 143         cx->blk_sub.gv = gv;                                            \
 144         cx->blk_sub.hasargs = 0;                                        \
 145         cx->blk_sub.dfoutgv = PL_defoutgv;                              \
 146         (void)SvREFCNT_inc(cx->blk_sub.dfoutgv)
 147
 148 #define POP_SAVEARRAY()                                         \
 149     STMT_START {                                                        \
 150         SvREFCNT_dec(GvAV(PL_defgv));                                   \
 151         GvAV(PL_defgv) = cx->blk_sub.savearray;                         \
 152     } STMT_END
 153
 154 /* junk in @_ spells trouble when cloning CVs and in pp_caller(), so don't
 155  * leave any (a fast av_clear(ary), basically) */
 156 #define CLEAR_ARGARRAY(ary) \
 157     STMT_START {                                                        \
 158         AvMAX(ary) += AvARRAY(ary) - AvALLOC(ary);                      \
 159         SvPVX(ary) = (char*)AvALLOC(ary);                               \
 160         AvFILLp(ary) = -1;                                              \
 161     } STMT_END
 162
 163 #define POPSUB(cx,sv)                                                   \
 164     STMT_START {                                                        \
 165         if (cx->blk_sub.hasargs) {                                      \
 166             POP_SAVEARRAY();                                            \
 167             /* abandon @_ if it got reified */                          \
 168             if (AvREAL(cx->blk_sub.argarray)) {                         \
 169                 SSize_t fill = AvFILLp(cx->blk_sub.argarray);           \
 170                 SvREFCNT_dec(cx->blk_sub.argarray);                     \
 171                 cx->blk_sub.argarray = newAV();                         \
 172                 av_extend(cx->blk_sub.argarray, fill);                  \
 173                 AvFLAGS(cx->blk_sub.argarray) = AVf_REIFY;              \
 174                 CX_CURPAD_SV(cx->blk_sub, 0) = (SV*)cx->blk_sub.argarray;       \
 175             }                                                           \
 176             else {                                                      \
 177                 CLEAR_ARGARRAY(cx->blk_sub.argarray);                   \
 178             }                                                           \
 179         }                                                               \
 180         sv = (SV*)cx->blk_sub.cv;                                       \
 181         if (sv && (CvDEPTH((CV*)sv) = cx->blk_sub.olddepth))            \
 182             sv = Nullsv;                                                \
 183     } STMT_END
 184
 185 #define LEAVESUB(sv)                                                    \
 186     STMT_START {                                                        \
 187         if (sv)                                                         \
 188             SvREFCNT_dec(sv);                                           \
 189     } STMT_END
 190
 191 #define POPFORMAT(cx)                                                   \
 192         setdefout(cx->blk_sub.dfoutgv);                                 \
 193         SvREFCNT_dec(cx->blk_sub.dfoutgv);
 194
 195 /* eval context */
 196 struct block_eval {
 197     I32         old_in_eval;
 198     I32         old_op_type;
 199     SV *        old_namesv;
 200     OP *        old_eval_root;
 201     SV *        cur_text;
 202     CV *        cv;
 203 };
 204
 205 #define PUSHEVAL(cx,n,fgv)                                              \
 206     STMT_START {                                                        \
 207         cx->blk_eval.old_in_eval = PL_in_eval;                          \
 208         cx->blk_eval.old_op_type = PL_op->op_type;                      \
 209         cx->blk_eval.old_namesv = (n ? newSVpv(n,0) : Nullsv);          \
 210         cx->blk_eval.old_eval_root = PL_eval_root;                      \
 211         cx->blk_eval.cur_text = PL_linestr;                             \
 212         cx->blk_eval.cv = Nullcv; /* set by doeval(), as applicable */  \
 213     } STMT_END
 214
 215 #define POPEVAL(cx)                                                     \
 216     STMT_START {                                                        \
 217         PL_in_eval = cx->blk_eval.old_in_eval;                          \
 218         optype = cx->blk_eval.old_op_type;                              \
 219         PL_eval_root = cx->blk_eval.old_eval_root;                      \
 220         if (cx->blk_eval.old_namesv)                                    \
 221             sv_2mortal(cx->blk_eval.old_namesv);                        \
 222     } STMT_END
 223
 224 /* loop context */
 225 struct block_loop {
 226     char *      label;
 227     I32         resetsp;
 228     OP *        redo_op;
 229     OP *        next_op;
 230     OP *        last_op;
 231 #ifdef USE_ITHREADS
 232     void *      iterdata;
 233     PAD         *oldcomppad;
 234 #else
 235     SV **       itervar;
 236 #endif
 237     SV *        itersave;
 238     SV *        iterlval;
 239     AV *        iterary;
 240     IV          iterix;
 241     IV          itermax;
 242 };
 243
 244 #ifdef USE_ITHREADS
 245 #  define CxITERVAR(c)                                                  \
 246         ((c)->blk_loop.iterdata                                         \
 247          ? (CxPADLOOP(cx)                                               \
 248             ? &CX_CURPAD_SV( (c)->blk_loop,                             \
 249                     INT2PTR(PADOFFSET, (c)->blk_loop.iterdata))         \
 250             : &GvSV((GV*)(c)->blk_loop.iterdata))                       \
 251          : (SV**)NULL)
 252 #  define CX_ITERDATA_SET(cx,idata)                                     \
 253         CX_CURPAD_SAVE(cx->blk_loop);                                   \
 254         if ((cx->blk_loop.iterdata = (idata)))                          \
 255             cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));       \
 256         else                                                            \
 257             cx->blk_loop.itersave = Nullsv;
 258 #else
 259 #  define CxITERVAR(c)          ((c)->blk_loop.itervar)
 260 #  define CX_ITERDATA_SET(cx,ivar)                                      \
 261         if ((cx->blk_loop.itervar = (SV**)(ivar)))                      \
 262             cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));       \
 263         else                                                            \
 264             cx->blk_loop.itersave = Nullsv;
 265 #endif
 266
 267 #define PUSHLOOP(cx, dat, s)                                            \
 268         cx->blk_loop.label = PL_curcop->cop_label;                      \
 269         cx->blk_loop.resetsp = s - PL_stack_base;                       \
 270         cx->blk_loop.redo_op = cLOOP->op_redoop;                        \
 271         cx->blk_loop.next_op = cLOOP->op_nextop;                        \
 272         cx->blk_loop.last_op = cLOOP->op_lastop;                        \
 273         cx->blk_loop.iterlval = Nullsv;                                 \
 274         cx->blk_loop.iterary = Nullav;                                  \
 275         cx->blk_loop.iterix = -1;                                       \
 276         CX_ITERDATA_SET(cx,dat);
 277
 278 #define POPLOOP(cx)                                                     \
 279         SvREFCNT_dec(cx->blk_loop.iterlval);                            \
 280         if (CxITERVAR(cx)) {                                            \
 281             SV **s_v_p = CxITERVAR(cx);                                 \
 282             sv_2mortal(*s_v_p);                                         \
 283             *s_v_p = cx->blk_loop.itersave;                             \
 284         }                                                               \
 285         if (cx->blk_loop.iterary && cx->blk_loop.iterary != PL_curstack)\
 286             SvREFCNT_dec(cx->blk_loop.iterary);
 287
 288 /* context common to subroutines, evals and loops */
 289 struct block {
 290     I32         blku_oldsp;     /* stack pointer to copy stuff down to */
 291     COP *       blku_oldcop;    /* old curcop pointer */
 292     I32         blku_oldretsp;  /* return stack index */
 293     I32         blku_oldmarksp; /* mark stack index */
 294     I32         blku_oldscopesp;        /* scope stack index */
 295     PMOP *      blku_oldpm;     /* values of pattern match vars */
 296     U8          blku_gimme;     /* is this block running in list context? */
 297
 298     union {
 299         struct block_sub        blku_sub;
 300         struct block_eval       blku_eval;
 301         struct block_loop       blku_loop;
 302     } blk_u;
 303 };
 304 #define blk_oldsp       cx_u.cx_blk.blku_oldsp
 305 #define blk_oldcop      cx_u.cx_blk.blku_oldcop
 306 #define blk_oldretsp    cx_u.cx_blk.blku_oldretsp
 307 #define blk_oldmarksp   cx_u.cx_blk.blku_oldmarksp
 308 #define blk_oldscopesp  cx_u.cx_blk.blku_oldscopesp
 309 #define blk_oldpm       cx_u.cx_blk.blku_oldpm
 310 #define blk_gimme       cx_u.cx_blk.blku_gimme
 311 #define blk_sub         cx_u.cx_blk.blk_u.blku_sub
 312 #define blk_eval        cx_u.cx_blk.blk_u.blku_eval
 313 #define blk_loop        cx_u.cx_blk.blk_u.blku_loop
 314
 315 /* Enter a block. */
 316 #define PUSHBLOCK(cx,t,sp) CXINC, cx = &cxstack[cxstack_ix],            \
 317         cx->cx_type             = t,                                    \
 318         cx->blk_oldsp           = sp - PL_stack_base,                   \
 319         cx->blk_oldcop          = PL_curcop,                            \
 320         cx->blk_oldmarksp       = PL_markstack_ptr - PL_markstack,      \
 321         cx->blk_oldscopesp      = PL_scopestack_ix,                     \
 322         cx->blk_oldretsp        = PL_retstack_ix,                       \
 323         cx->blk_oldpm           = PL_curpm,                             \
 324         cx->blk_gimme           = (U8)gimme;                            \
 325         DEBUG_l( PerlIO_printf(Perl_debug_log, "Entering block %ld, type %s\n", \
 326                     (long)cxstack_ix, PL_block_type[CxTYPE(cx)]); )
 327
 328 /* Exit a block (RETURN and LAST). */
 329 #define POPBLOCK(cx,pm) cx = &cxstack[cxstack_ix--],                    \
 330         newsp            = PL_stack_base + cx->blk_oldsp,               \
 331         PL_curcop        = cx->blk_oldcop,                              \
 332         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
 333         PL_scopestack_ix = cx->blk_oldscopesp,                          \
 334         PL_retstack_ix   = cx->blk_oldretsp,                            \
 335         pm               = cx->blk_oldpm,                               \
 336         gimme            = cx->blk_gimme;                               \
 337         DEBUG_l( PerlIO_printf(Perl_debug_log, "Leaving block %ld, type %s\n",          \
 338                     (long)cxstack_ix+1,PL_block_type[CxTYPE(cx)]); )
 339
 340 /* Continue a block elsewhere (NEXT and REDO). */
 341 #define TOPBLOCK(cx) cx  = &cxstack[cxstack_ix],                        \
 342         PL_stack_sp      = PL_stack_base + cx->blk_oldsp,               \
 343         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
 344         PL_scopestack_ix = cx->blk_oldscopesp,                          \
 345         PL_retstack_ix   = cx->blk_oldretsp,                            \
 346         PL_curpm         = cx->blk_oldpm
 347
 348 /* substitution context */
 349 struct subst {
 350     I32         sbu_iters;
 351     I32         sbu_maxiters;
 352     I32         sbu_rflags;
 353     I32         sbu_oldsave;
 354     bool        sbu_once;
 355     bool        sbu_rxtainted;
 356     char *      sbu_orig;
 357     SV *        sbu_dstr;
 358     SV *        sbu_targ;
 359     char *      sbu_s;
 360     char *      sbu_m;
 361     char *      sbu_strend;
 362     void *      sbu_rxres;
 363     REGEXP *    sbu_rx;
 364 };
 365 #define sb_iters        cx_u.cx_subst.sbu_iters
 366 #define sb_maxiters     cx_u.cx_subst.sbu_maxiters
 367 #define sb_rflags       cx_u.cx_subst.sbu_rflags
 368 #define sb_oldsave      cx_u.cx_subst.sbu_oldsave
 369 #define sb_once         cx_u.cx_subst.sbu_once
 370 #define sb_rxtainted    cx_u.cx_subst.sbu_rxtainted
 371 #define sb_orig         cx_u.cx_subst.sbu_orig
 372 #define sb_dstr         cx_u.cx_subst.sbu_dstr
 373 #define sb_targ         cx_u.cx_subst.sbu_targ
 374 #define sb_s            cx_u.cx_subst.sbu_s
 375 #define sb_m            cx_u.cx_subst.sbu_m
 376 #define sb_strend       cx_u.cx_subst.sbu_strend
 377 #define sb_rxres        cx_u.cx_subst.sbu_rxres
 378 #define sb_rx           cx_u.cx_subst.sbu_rx
 379
 380 #define PUSHSUBST(cx) CXINC, cx = &cxstack[cxstack_ix],                 \
 381         cx->sb_iters            = iters,                                \
 382         cx->sb_maxiters         = maxiters,                             \
 383         cx->sb_rflags           = r_flags,                              \
 384         cx->sb_oldsave          = oldsave,                              \
 385         cx->sb_once             = once,                                 \
 386         cx->sb_rxtainted        = rxtainted,                            \
 387         cx->sb_orig             = orig,                                 \
 388         cx->sb_dstr             = dstr,                                 \
 389         cx->sb_targ             = targ,                                 \
 390         cx->sb_s                = s,                                    \
 391         cx->sb_m                = m,                                    \
 392         cx->sb_strend           = strend,                               \
 393         cx->sb_rxres            = Null(void*),                          \
 394         cx->sb_rx               = rx,                                   \
 395         cx->cx_type             = CXt_SUBST;                            \
 396         rxres_save(&cx->sb_rxres, rx)
 397
 398 #define POPSUBST(cx) cx = &cxstack[cxstack_ix--];                       \
 399         rxres_free(&cx->sb_rxres)
 400
 401 struct context {
 402     U32         cx_type;        /* what kind of context this is */
 403     union {
 404         struct block    cx_blk;
 405         struct subst    cx_subst;
 406     } cx_u;
 407 };
 408
 409 #define CXTYPEMASK      0xff
 410 #define CXt_NULL        0
 411 #define CXt_SUB         1
 412 #define CXt_EVAL        2
 413 #define CXt_LOOP        3
 414 #define CXt_SUBST       4
 415 #define CXt_BLOCK       5
 416 #define CXt_FORMAT      6
 417
 418 /* private flags for CXt_EVAL */
 419 #define CXp_REAL        0x00000100      /* truly eval'', not a lookalike */
 420 #define CXp_TRYBLOCK    0x00000200      /* eval{}, not eval'' or similar */
 421
 422 #ifdef USE_ITHREADS
 423 /* private flags for CXt_LOOP */
 424 #  define CXp_PADVAR    0x00000100      /* itervar lives on pad, iterdata
 425                                            has pad offset; if not set,
 426                                            iterdata holds GV* */
 427 #  define CxPADLOOP(c)  (((c)->cx_type & (CXt_LOOP|CXp_PADVAR))         \
 428                          == (CXt_LOOP|CXp_PADVAR))
 429 #endif
 430
 431 #define CxTYPE(c)       ((c)->cx_type & CXTYPEMASK)
 432 #define CxREALEVAL(c)   (((c)->cx_type & (CXt_EVAL|CXp_REAL))           \
 433                          == (CXt_EVAL|CXp_REAL))
 434 #define CxTRYBLOCK(c)   (((c)->cx_type & (CXt_EVAL|CXp_TRYBLOCK))       \
 435                          == (CXt_EVAL|CXp_TRYBLOCK))
 436
 437 #define CXINC (cxstack_ix < cxstack_max ? ++cxstack_ix : (cxstack_ix = cxinc()))
 438
 439 /*
 440 =head1 "Gimme" Values
 441 */
 442
 443 /*
 444 =for apidoc AmU||G_SCALAR
 445 Used to indicate scalar context.  See C<GIMME_V>, C<GIMME>, and
 446 L<perlcall>.
 447
 448 =for apidoc AmU||G_ARRAY
 449 Used to indicate list context.  See C<GIMME_V>, C<GIMME> and
 450 L<perlcall>.
 451
 452 =for apidoc AmU||G_VOID
 453 Used to indicate void context.  See C<GIMME_V> and L<perlcall>.
 454
 455 =for apidoc AmU||G_DISCARD
 456 Indicates that arguments returned from a callback should be discarded.  See
 457 L<perlcall>.
 458
 459 =for apidoc AmU||G_EVAL
 460
 461 Used to force a Perl C<eval> wrapper around a callback.  See
 462 L<perlcall>.
 463
 464 =for apidoc AmU||G_NOARGS
 465
 466 Indicates that no arguments are being sent to a callback.  See
 467 L<perlcall>.
 468
 469 =cut
 470 */
 471
 472 #define G_SCALAR        0
 473 #define G_ARRAY         1
 474 #define G_VOID          128     /* skip this bit when adding flags below */
 475
 476 /* extra flags for Perl_call_* routines */
 477 #define G_DISCARD       2       /* Call FREETMPS. */
 478 #define G_EVAL          4       /* Assume eval {} around subroutine call. */
 479 #define G_NOARGS        8       /* Don't construct a @_ array. */
 480 #define G_KEEPERR      16       /* Append errors to $@, don't overwrite it */
 481 #define G_NODEBUG      32       /* Disable debugging at toplevel.  */
 482 #define G_METHOD       64       /* Calling method. */
 483
 484 /* flag bits for PL_in_eval */
 485 #define EVAL_NULL       0       /* not in an eval */
 486 #define EVAL_INEVAL     1       /* some enclosing scope is an eval */
 487 #define EVAL_WARNONLY   2       /* used by yywarn() when calling yyerror() */
 488 #define EVAL_KEEPERR    4       /* set by Perl_call_sv if G_KEEPERR */
 489 #define EVAL_INREQUIRE  8       /* The code is being required. */
 490
 491 /* Support for switching (stack and block) contexts.
 492  * This ensures magic doesn't invalidate local stack and cx pointers.
 493  */
 494
 495 #define PERLSI_UNKNOWN          -1
 496 #define PERLSI_UNDEF            0
 497 #define PERLSI_MAIN             1
 498 #define PERLSI_MAGIC            2
 499 #define PERLSI_SORT             3
 500 #define PERLSI_SIGNAL           4
 501 #define PERLSI_OVERLOAD         5
 502 #define PERLSI_DESTROY          6
 503 #define PERLSI_WARNHOOK         7
 504 #define PERLSI_DIEHOOK          8
 505 #define PERLSI_REQUIRE          9
 506
 507 struct stackinfo {
 508     AV *                si_stack;       /* stack for current runlevel */
 509     PERL_CONTEXT *      si_cxstack;     /* context stack for runlevel */
 510     I32                 si_cxix;        /* current context index */
 511     I32                 si_cxmax;       /* maximum allocated index */
 512     I32                 si_type;        /* type of runlevel */
 513     struct stackinfo *  si_prev;
 514     struct stackinfo *  si_next;
 515     I32                 si_markoff;     /* offset where markstack begins for us.
 516                                          * currently used only with DEBUGGING,
 517                                          * but not #ifdef-ed for bincompat */
 518 };
 519
 520 typedef struct stackinfo PERL_SI;
 521
 522 #define cxstack         (PL_curstackinfo->si_cxstack)
 523 #define cxstack_ix      (PL_curstackinfo->si_cxix)
 524 #define cxstack_max     (PL_curstackinfo->si_cxmax)
 525
 526 #ifdef DEBUGGING
 527 #  define       SET_MARK_OFFSET \
 528     PL_curstackinfo->si_markoff = PL_markstack_ptr - PL_markstack
 529 #else
 530 #  define       SET_MARK_OFFSET NOOP
 531 #endif
 532
 533 #define PUSHSTACKi(type) \
 534     STMT_START {                                                        \
 535         PERL_SI *next = PL_curstackinfo->si_next;                       \
 536         if (!next) {                                                    \
 537             next = new_stackinfo(32, 2048/sizeof(PERL_CONTEXT) - 1);    \
 538             next->si_prev = PL_curstackinfo;                            \
 539             PL_curstackinfo->si_next = next;                            \
 540         }                                                               \
 541         next->si_type = type;                                           \
 542         next->si_cxix = -1;                                             \
 543         AvFILLp(next->si_stack) = 0;                                    \
 544         SWITCHSTACK(PL_curstack,next->si_stack);                        \
 545         PL_curstackinfo = next;                                         \
 546         SET_MARK_OFFSET;                                                \
 547     } STMT_END
 548
 549 #define PUSHSTACK PUSHSTACKi(PERLSI_UNKNOWN)
 550
 551 /* POPSTACK works with PL_stack_sp, so it may need to be bracketed by
 552  * PUTBACK/SPAGAIN to flush/refresh any local SP that may be active */
 553 #define POPSTACK \
 554     STMT_START {                                                        \
 555         dSP;                                                            \
 556         PERL_SI *prev = PL_curstackinfo->si_prev;                       \
 557         if (!prev) {                                                    \
 558             PerlIO_printf(Perl_error_log, "panic: POPSTACK\n");         \
 559             my_exit(1);                                                 \
 560         }                                                               \
 561         SWITCHSTACK(PL_curstack,prev->si_stack);                        \
 562         /* don't free prev here, free them all at the END{} */          \
 563         PL_curstackinfo = prev;                                         \
 564     } STMT_END
 565
 566 #define POPSTACK_TO(s) \
 567     STMT_START {                                                        \
 568         while (PL_curstack != s) {                                      \
 569             dounwind(-1);                                               \
 570             POPSTACK;                                                   \
 571         }                                                               \
 572     } STMT_END