cop.h

   1 /*    cop.h
   2  *
   3  *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
   4  *    2000, 2001, 2002, 2003, 2004, 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 #ifndef USE_5005THREADS
 117     AV *        savearray;
 118 #endif /* USE_5005THREADS */
 119     AV *        argarray;
 120     long        olddepth;
 121     U8          hasargs;
 122     U8          lval;           /* XXX merge lval and hasargs? */
 123     PAD         *oldcomppad;
 124 };
 125
 126 /* base for the next two macros. Don't use directly.
 127  * Note that the refcnt of the cv is incremented twice;  The CX one is
 128  * decremented by LEAVESUB, the other by LEAVE. */
 129
 130 #define PUSHSUB_BASE(cx)                                                \
 131         cx->blk_sub.cv = cv;                                            \
 132         cx->blk_sub.olddepth = CvDEPTH(cv);                             \
 133         cx->blk_sub.hasargs = hasargs;                                  \
 134         if (!CvDEPTH(cv)) {                                             \
 135             (void)SvREFCNT_inc(cv);                                     \
 136             (void)SvREFCNT_inc(cv);                                     \
 137             SAVEFREESV(cv);                                             \
 138         }
 139
 140
 141 #define PUSHSUB(cx)                                                     \
 142         PUSHSUB_BASE(cx)                                                \
 143         cx->blk_sub.lval = PL_op->op_private &                          \
 144                               (OPpLVAL_INTRO|OPpENTERSUB_INARGS);
 145
 146 /* variant for use by OP_DBSTATE, where op_private holds hint bits */
 147 #define PUSHSUB_DB(cx)                                                  \
 148         PUSHSUB_BASE(cx)                                                \
 149         cx->blk_sub.lval = 0;
 150
 151
 152 #define PUSHFORMAT(cx)                                                  \
 153         cx->blk_sub.cv = cv;                                            \
 154         cx->blk_sub.gv = gv;                                            \
 155         cx->blk_sub.hasargs = 0;                                        \
 156         cx->blk_sub.dfoutgv = PL_defoutgv;                              \
 157         (void)SvREFCNT_inc(cx->blk_sub.dfoutgv)
 158
 159 #ifdef USE_5005THREADS
 160 #  define POP_SAVEARRAY() NOOP
 161 #else
 162 #  define POP_SAVEARRAY()                                               \
 163     STMT_START {                                                        \
 164         SvREFCNT_dec(GvAV(PL_defgv));                                   \
 165         GvAV(PL_defgv) = cx->blk_sub.savearray;                         \
 166     } STMT_END
 167 #endif /* USE_5005THREADS */
 168
 169 /* junk in @_ spells trouble when cloning CVs and in pp_caller(), so don't
 170  * leave any (a fast av_clear(ary), basically) */
 171 #define CLEAR_ARGARRAY(ary) \
 172     STMT_START {                                                        \
 173         AvMAX(ary) += AvARRAY(ary) - AvALLOC(ary);                      \
 174         SvPV_set(ary, (char*)AvALLOC(ary));                             \
 175         AvFILLp(ary) = -1;                                              \
 176     } STMT_END
 177
 178 #define POPSUB(cx,sv)                                                   \
 179     STMT_START {                                                        \
 180         if (cx->blk_sub.hasargs) {                                      \
 181             POP_SAVEARRAY();                                            \
 182             /* abandon @_ if it got reified */                          \
 183             if (AvREAL(cx->blk_sub.argarray)) {                         \
 184                 SSize_t fill = AvFILLp(cx->blk_sub.argarray);           \
 185                 SvREFCNT_dec(cx->blk_sub.argarray);                     \
 186                 cx->blk_sub.argarray = newAV();                         \
 187                 av_extend(cx->blk_sub.argarray, fill);                  \
 188                 AvFLAGS(cx->blk_sub.argarray) = AVf_REIFY;              \
 189                 CX_CURPAD_SV(cx->blk_sub, 0) = (SV*)cx->blk_sub.argarray;       \
 190             }                                                           \
 191             else {                                                      \
 192                 CLEAR_ARGARRAY(cx->blk_sub.argarray);                   \
 193             }                                                           \
 194         }                                                               \
 195         sv = (SV*)cx->blk_sub.cv;                                       \
 196         if (sv && (CvDEPTH((CV*)sv) = cx->blk_sub.olddepth))            \
 197             sv = Nullsv;                                                \
 198     } STMT_END
 199
 200 #define LEAVESUB(sv)                                                    \
 201     STMT_START {                                                        \
 202         if (sv)                                                         \
 203             SvREFCNT_dec(sv);                                           \
 204     } STMT_END
 205
 206 #define POPFORMAT(cx)                                                   \
 207         setdefout(cx->blk_sub.dfoutgv);                                 \
 208         SvREFCNT_dec(cx->blk_sub.dfoutgv);
 209
 210 /* eval context */
 211 struct block_eval {
 212     I32         old_in_eval;
 213     I32         old_op_type;
 214     SV *        old_namesv;
 215     OP *        old_eval_root;
 216     SV *        cur_text;
 217     CV *        cv;
 218 };
 219
 220 #define PUSHEVAL(cx,n,fgv)                                              \
 221     STMT_START {                                                        \
 222         cx->blk_eval.old_in_eval = PL_in_eval;                          \
 223         cx->blk_eval.old_op_type = PL_op->op_type;                      \
 224         cx->blk_eval.old_namesv = (n ? newSVpv(n,0) : Nullsv);          \
 225         cx->blk_eval.old_eval_root = PL_eval_root;                      \
 226         cx->blk_eval.cur_text = PL_linestr;                             \
 227         cx->blk_eval.cv = Nullcv; /* set by doeval(), as applicable */  \
 228     } STMT_END
 229
 230 #define POPEVAL(cx)                                                     \
 231     STMT_START {                                                        \
 232         PL_in_eval = cx->blk_eval.old_in_eval;                          \
 233         optype = cx->blk_eval.old_op_type;                              \
 234         PL_eval_root = cx->blk_eval.old_eval_root;                      \
 235         if (cx->blk_eval.old_namesv)                                    \
 236             sv_2mortal(cx->blk_eval.old_namesv);                        \
 237     } STMT_END
 238
 239 /* loop context */
 240 struct block_loop {
 241     char *      label;
 242     I32         resetsp;
 243     OP *        redo_op;
 244     OP *        next_op;
 245     OP *        last_op;
 246 #ifdef USE_ITHREADS
 247     void *      iterdata;
 248     PAD         *oldcomppad;
 249 #else
 250     SV **       itervar;
 251 #endif
 252     SV *        itersave;
 253     SV *        iterlval;
 254     AV *        iterary;
 255     IV          iterix;
 256     IV          itermax;
 257 };
 258
 259 #ifdef USE_ITHREADS
 260 #  define CxITERVAR(c)                                                  \
 261         ((c)->blk_loop.iterdata                                         \
 262          ? (CxPADLOOP(cx)                                               \
 263             ? &CX_CURPAD_SV( (c)->blk_loop,                             \
 264                     INT2PTR(PADOFFSET, (c)->blk_loop.iterdata))         \
 265             : &GvSV((GV*)(c)->blk_loop.iterdata))                       \
 266          : (SV**)NULL)
 267 #  define CX_ITERDATA_SET(cx,idata)                                     \
 268         CX_CURPAD_SAVE(cx->blk_loop);                                   \
 269         if ((cx->blk_loop.iterdata = (idata)))                          \
 270             cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));       \
 271         else                                                            \
 272             cx->blk_loop.itersave = Nullsv;
 273 #else
 274 #  define CxITERVAR(c)          ((c)->blk_loop.itervar)
 275 #  define CX_ITERDATA_SET(cx,ivar)                                      \
 276         if ((cx->blk_loop.itervar = (SV**)(ivar)))                      \
 277             cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));       \
 278         else                                                            \
 279             cx->blk_loop.itersave = Nullsv;
 280 #endif
 281
 282 #define PUSHLOOP(cx, dat, s)                                            \
 283         cx->blk_loop.label = PL_curcop->cop_label;                      \
 284         cx->blk_loop.resetsp = s - PL_stack_base;                       \
 285         cx->blk_loop.redo_op = cLOOP->op_redoop;                        \
 286         cx->blk_loop.next_op = cLOOP->op_nextop;                        \
 287         cx->blk_loop.last_op = cLOOP->op_lastop;                        \
 288         cx->blk_loop.iterlval = Nullsv;                                 \
 289         cx->blk_loop.iterary = Nullav;                                  \
 290         cx->blk_loop.iterix = -1;                                       \
 291         CX_ITERDATA_SET(cx,dat);
 292
 293 #define POPLOOP(cx)                                                     \
 294         SvREFCNT_dec(cx->blk_loop.iterlval);                            \
 295         if (CxITERVAR(cx)) {                                            \
 296             SV **s_v_p = CxITERVAR(cx);                                 \
 297             sv_2mortal(*s_v_p);                                         \
 298             *s_v_p = cx->blk_loop.itersave;                             \
 299         }                                                               \
 300         if (cx->blk_loop.iterary && cx->blk_loop.iterary != PL_curstack)\
 301             SvREFCNT_dec(cx->blk_loop.iterary);
 302
 303 /* context common to subroutines, evals and loops */
 304 struct block {
 305     I32         blku_oldsp;     /* stack pointer to copy stuff down to */
 306     COP *       blku_oldcop;    /* old curcop pointer */
 307     I32         blku_oldretsp;  /* return stack index */
 308     I32         blku_oldmarksp; /* mark stack index */
 309     I32         blku_oldscopesp;        /* scope stack index */
 310     PMOP *      blku_oldpm;     /* values of pattern match vars */
 311     U8          blku_gimme;     /* is this block running in list context? */
 312
 313     union {
 314         struct block_sub        blku_sub;
 315         struct block_eval       blku_eval;
 316         struct block_loop       blku_loop;
 317     } blk_u;
 318 };
 319 #define blk_oldsp       cx_u.cx_blk.blku_oldsp
 320 #define blk_oldcop      cx_u.cx_blk.blku_oldcop
 321 #define blk_oldretsp    cx_u.cx_blk.blku_oldretsp
 322 #define blk_oldmarksp   cx_u.cx_blk.blku_oldmarksp
 323 #define blk_oldscopesp  cx_u.cx_blk.blku_oldscopesp
 324 #define blk_oldpm       cx_u.cx_blk.blku_oldpm
 325 #define blk_gimme       cx_u.cx_blk.blku_gimme
 326 #define blk_sub         cx_u.cx_blk.blk_u.blku_sub
 327 #define blk_eval        cx_u.cx_blk.blk_u.blku_eval
 328 #define blk_loop        cx_u.cx_blk.blk_u.blku_loop
 329
 330 /* Enter a block. */
 331 #define PUSHBLOCK(cx,t,sp) CXINC, cx = &cxstack[cxstack_ix],            \
 332         cx->cx_type             = t,                                    \
 333         cx->blk_oldsp           = sp - PL_stack_base,                   \
 334         cx->blk_oldcop          = PL_curcop,                            \
 335         cx->blk_oldmarksp       = PL_markstack_ptr - PL_markstack,      \
 336         cx->blk_oldscopesp      = PL_scopestack_ix,                     \
 337         cx->blk_oldretsp        = PL_retstack_ix,                       \
 338         cx->blk_oldpm           = PL_curpm,                             \
 339         cx->blk_gimme           = (U8)gimme;                            \
 340         DEBUG_l( PerlIO_printf(Perl_debug_log, "Entering block %ld, type %s\n", \
 341                     (long)cxstack_ix, PL_block_type[CxTYPE(cx)]); )
 342
 343 /* Exit a block (RETURN and LAST). */
 344 #define POPBLOCK(cx,pm) cx = &cxstack[cxstack_ix--],                    \
 345         newsp            = PL_stack_base + cx->blk_oldsp,               \
 346         PL_curcop        = cx->blk_oldcop,                              \
 347         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
 348         PL_scopestack_ix = cx->blk_oldscopesp,                          \
 349         PL_retstack_ix   = cx->blk_oldretsp,                            \
 350         pm               = cx->blk_oldpm,                               \
 351         gimme            = cx->blk_gimme;                               \
 352         DEBUG_SCOPE("POPBLOCK");                                        \
 353         DEBUG_l( PerlIO_printf(Perl_debug_log, "Leaving block %ld, type %s\n",          \
 354                     (long)cxstack_ix+1,PL_block_type[CxTYPE(cx)]); )
 355
 356 /* Continue a block elsewhere (NEXT and REDO). */
 357 #define TOPBLOCK(cx) cx  = &cxstack[cxstack_ix],                        \
 358         PL_stack_sp      = PL_stack_base + cx->blk_oldsp,               \
 359         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
 360         PL_scopestack_ix = cx->blk_oldscopesp,                          \
 361         PL_retstack_ix   = cx->blk_oldretsp,                            \
 362         PL_curpm         = cx->blk_oldpm;                               \
 363         DEBUG_SCOPE("TOPBLOCK");
 364
 365 /* substitution context */
 366 struct subst {
 367     I32         sbu_iters;
 368     I32         sbu_maxiters;
 369     I32         sbu_rflags;
 370     I32         sbu_oldsave;
 371     bool        sbu_once;
 372     bool        sbu_rxtainted;
 373     char *      sbu_orig;
 374     SV *        sbu_dstr;
 375     SV *        sbu_targ;
 376     char *      sbu_s;
 377     char *      sbu_m;
 378     char *      sbu_strend;
 379     void *      sbu_rxres;
 380     REGEXP *    sbu_rx;
 381 };
 382 #define sb_iters        cx_u.cx_subst.sbu_iters
 383 #define sb_maxiters     cx_u.cx_subst.sbu_maxiters
 384 #define sb_rflags       cx_u.cx_subst.sbu_rflags
 385 #define sb_oldsave      cx_u.cx_subst.sbu_oldsave
 386 #define sb_once         cx_u.cx_subst.sbu_once
 387 #define sb_rxtainted    cx_u.cx_subst.sbu_rxtainted
 388 #define sb_orig         cx_u.cx_subst.sbu_orig
 389 #define sb_dstr         cx_u.cx_subst.sbu_dstr
 390 #define sb_targ         cx_u.cx_subst.sbu_targ
 391 #define sb_s            cx_u.cx_subst.sbu_s
 392 #define sb_m            cx_u.cx_subst.sbu_m
 393 #define sb_strend       cx_u.cx_subst.sbu_strend
 394 #define sb_rxres        cx_u.cx_subst.sbu_rxres
 395 #define sb_rx           cx_u.cx_subst.sbu_rx
 396
 397 #define PUSHSUBST(cx) CXINC, cx = &cxstack[cxstack_ix],                 \
 398         cx->sb_iters            = iters,                                \
 399         cx->sb_maxiters         = maxiters,                             \
 400         cx->sb_rflags           = r_flags,                              \
 401         cx->sb_oldsave          = oldsave,                              \
 402         cx->sb_once             = once,                                 \
 403         cx->sb_rxtainted        = rxtainted,                            \
 404         cx->sb_orig             = orig,                                 \
 405         cx->sb_dstr             = dstr,                                 \
 406         cx->sb_targ             = targ,                                 \
 407         cx->sb_s                = s,                                    \
 408         cx->sb_m                = m,                                    \
 409         cx->sb_strend           = strend,                               \
 410         cx->sb_rxres            = Null(void*),                          \
 411         cx->sb_rx               = rx,                                   \
 412         cx->cx_type             = CXt_SUBST;                            \
 413         rxres_save(&cx->sb_rxres, rx)
 414
 415 #define POPSUBST(cx) cx = &cxstack[cxstack_ix--];                       \
 416         rxres_free(&cx->sb_rxres)
 417
 418 struct context {
 419     U32         cx_type;        /* what kind of context this is */
 420     union {
 421         struct block    cx_blk;
 422         struct subst    cx_subst;
 423     } cx_u;
 424 };
 425
 426 #define CXTYPEMASK      0xff
 427 #define CXt_NULL        0
 428 #define CXt_SUB         1
 429 #define CXt_EVAL        2
 430 #define CXt_LOOP        3
 431 #define CXt_SUBST       4
 432 #define CXt_BLOCK       5
 433 #define CXt_FORMAT      6
 434
 435 /* private flags for CXt_EVAL */
 436 #define CXp_REAL        0x00000100      /* truly eval'', not a lookalike */
 437 #define CXp_TRYBLOCK    0x00000200      /* eval{}, not eval'' or similar */
 438
 439 #ifdef USE_ITHREADS
 440 /* private flags for CXt_LOOP */
 441 #  define CXp_PADVAR    0x00000100      /* itervar lives on pad, iterdata
 442                                            has pad offset; if not set,
 443                                            iterdata holds GV* */
 444 #  define CxPADLOOP(c)  (((c)->cx_type & (CXt_LOOP|CXp_PADVAR))         \
 445                          == (CXt_LOOP|CXp_PADVAR))
 446 #endif
 447
 448 #define CxTYPE(c)       ((c)->cx_type & CXTYPEMASK)
 449 #define CxREALEVAL(c)   (((c)->cx_type & (CXt_EVAL|CXp_REAL))           \
 450                          == (CXt_EVAL|CXp_REAL))
 451 #define CxTRYBLOCK(c)   (((c)->cx_type & (CXt_EVAL|CXp_TRYBLOCK))       \
 452                          == (CXt_EVAL|CXp_TRYBLOCK))
 453
 454 #define CXINC (cxstack_ix < cxstack_max ? ++cxstack_ix : (cxstack_ix = cxinc()))
 455
 456 /*
 457 =head1 "Gimme" Values
 458 */
 459
 460 /*
 461 =for apidoc AmU||G_SCALAR
 462 Used to indicate scalar context.  See C<GIMME_V>, C<GIMME>, and
 463 L<perlcall>.
 464
 465 =for apidoc AmU||G_ARRAY
 466 Used to indicate list context.  See C<GIMME_V>, C<GIMME> and
 467 L<perlcall>.
 468
 469 =for apidoc AmU||G_VOID
 470 Used to indicate void context.  See C<GIMME_V> and L<perlcall>.
 471
 472 =for apidoc AmU||G_DISCARD
 473 Indicates that arguments returned from a callback should be discarded.  See
 474 L<perlcall>.
 475
 476 =for apidoc AmU||G_EVAL
 477
 478 Used to force a Perl C<eval> wrapper around a callback.  See
 479 L<perlcall>.
 480
 481 =for apidoc AmU||G_NOARGS
 482
 483 Indicates that no arguments are being sent to a callback.  See
 484 L<perlcall>.
 485
 486 =cut
 487 */
 488
 489 #define G_SCALAR        0
 490 #define G_ARRAY         1
 491 #define G_VOID          128     /* skip this bit when adding flags below */
 492
 493 /* extra flags for Perl_call_* routines */
 494 #define G_DISCARD       2       /* Call FREETMPS. */
 495 #define G_EVAL          4       /* Assume eval {} around subroutine call. */
 496 #define G_NOARGS        8       /* Don't construct a @_ array. */
 497 #define G_KEEPERR      16       /* Append errors to $@, don't overwrite it */
 498 #define G_NODEBUG      32       /* Disable debugging at toplevel.  */
 499 #define G_METHOD       64       /* Calling method. */
 500
 501 /* flag bits for PL_in_eval */
 502 #define EVAL_NULL       0       /* not in an eval */
 503 #define EVAL_INEVAL     1       /* some enclosing scope is an eval */
 504 #define EVAL_WARNONLY   2       /* used by yywarn() when calling yyerror() */
 505 #define EVAL_KEEPERR    4       /* set by Perl_call_sv if G_KEEPERR */
 506 #define EVAL_INREQUIRE  8       /* The code is being required. */
 507
 508 /* Support for switching (stack and block) contexts.
 509  * This ensures magic doesn't invalidate local stack and cx pointers.
 510  */
 511
 512 #define PERLSI_UNKNOWN          -1
 513 #define PERLSI_UNDEF            0
 514 #define PERLSI_MAIN             1
 515 #define PERLSI_MAGIC            2
 516 #define PERLSI_SORT             3
 517 #define PERLSI_SIGNAL           4
 518 #define PERLSI_OVERLOAD         5
 519 #define PERLSI_DESTROY          6
 520 #define PERLSI_WARNHOOK         7
 521 #define PERLSI_DIEHOOK          8
 522 #define PERLSI_REQUIRE          9
 523
 524 struct stackinfo {
 525     AV *                si_stack;       /* stack for current runlevel */
 526     PERL_CONTEXT *      si_cxstack;     /* context stack for runlevel */
 527     I32                 si_cxix;        /* current context index */
 528     I32                 si_cxmax;       /* maximum allocated index */
 529     I32                 si_type;        /* type of runlevel */
 530     struct stackinfo *  si_prev;
 531     struct stackinfo *  si_next;
 532     I32                 si_markoff;     /* offset where markstack begins for us.
 533                                          * currently used only with DEBUGGING,
 534                                          * but not #ifdef-ed for bincompat */
 535 };
 536
 537 typedef struct stackinfo PERL_SI;
 538
 539 #define cxstack         (PL_curstackinfo->si_cxstack)
 540 #define cxstack_ix      (PL_curstackinfo->si_cxix)
 541 #define cxstack_max     (PL_curstackinfo->si_cxmax)
 542
 543 #ifdef DEBUGGING
 544 #  define       SET_MARK_OFFSET \
 545     PL_curstackinfo->si_markoff = PL_markstack_ptr - PL_markstack
 546 #else
 547 #  define       SET_MARK_OFFSET NOOP
 548 #endif
 549
 550 #define PUSHSTACKi(type) \
 551     STMT_START {                                                        \
 552         PERL_SI *next = PL_curstackinfo->si_next;                       \
 553         if (!next) {                                                    \
 554             next = new_stackinfo(32, 2048/sizeof(PERL_CONTEXT) - 1);    \
 555             next->si_prev = PL_curstackinfo;                            \
 556             PL_curstackinfo->si_next = next;                            \
 557         }                                                               \
 558         next->si_type = type;                                           \
 559         next->si_cxix = -1;                                             \
 560         AvFILLp(next->si_stack) = 0;                                    \
 561         SWITCHSTACK(PL_curstack,next->si_stack);                        \
 562         PL_curstackinfo = next;                                         \
 563         SET_MARK_OFFSET;                                                \
 564     } STMT_END
 565
 566 #define PUSHSTACK PUSHSTACKi(PERLSI_UNKNOWN)
 567
 568 /* POPSTACK works with PL_stack_sp, so it may need to be bracketed by
 569  * PUTBACK/SPAGAIN to flush/refresh any local SP that may be active */
 570 #define POPSTACK \
 571     STMT_START {                                                        \
 572         dSP;                                                            \
 573         PERL_SI *prev = PL_curstackinfo->si_prev;                       \
 574         if (!prev) {                                                    \
 575             PerlIO_printf(Perl_error_log, "panic: POPSTACK\n");         \
 576             my_exit(1);                                                 \
 577         }                                                               \
 578         SWITCHSTACK(PL_curstack,prev->si_stack);                        \
 579         /* don't free prev here, free them all at the END{} */          \
 580         PL_curstackinfo = prev;                                         \
 581     } STMT_END
 582
 583 #define POPSTACK_TO(s) \
 584     STMT_START {                                                        \
 585         while (PL_curstack != s) {                                      \
 586             dounwind(-1);                                               \
 587             POPSTACK;                                                   \
 588         }                                                               \
 589     } STMT_END
 590
 591 #define IN_PERL_COMPILETIME     (PL_curcop == &PL_compiling)
 592 #define IN_PERL_RUNTIME         (PL_curcop != &PL_compiling)
 593