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 /* A jmpenv packages the state required to perform a proper non-local jump.
  17  * Note that there is a start_env initialized when perl starts, and top_env
  18  * points to this initially, so top_env should always be non-null.
  19  *
  20  * Existence of a non-null top_env->je_prev implies it is valid to call
  21  * longjmp() at that runlevel (we make sure start_env.je_prev is always
  22  * null to ensure this).
  23  *
  24  * je_mustcatch, when set at any runlevel to TRUE, means eval ops must
  25  * establish a local jmpenv to handle exception traps.  Care must be taken
  26  * to restore the previous value of je_mustcatch before exiting the
  27  * stack frame iff JMPENV_PUSH was not called in that stack frame.
  28  * GSAR 97-03-27
  29  */
  30
  31 struct jmpenv {
  32     struct jmpenv *     je_prev;
  33     Sigjmp_buf          je_buf;         /* only for use if !je_throw */
  34     int                 je_ret;         /* last exception thrown */
  35     bool                je_mustcatch;   /* need to call longjmp()? */
  36 };
  37
  38 typedef struct jmpenv JMPENV;
  39
  40 #ifdef OP_IN_REGISTER
  41 #define OP_REG_TO_MEM   PL_opsave = op
  42 #define OP_MEM_TO_REG   op = PL_opsave
  43 #else
  44 #define OP_REG_TO_MEM   NOOP
  45 #define OP_MEM_TO_REG   NOOP
  46 #endif
  47
  48 /*
  49  * How to build the first jmpenv.
  50  *
  51  * top_env needs to be non-zero. It points to an area
  52  * in which longjmp() stuff is stored, as C callstack
  53  * info there at least is thread specific this has to
  54  * be per-thread. Otherwise a 'die' in a thread gives
  55  * that thread the C stack of last thread to do an eval {}!
  56  */
  57
  58 #define JMPENV_BOOTSTRAP \
  59     STMT_START {                                \
  60         Zero(&PL_start_env, 1, JMPENV);         \
  61         PL_start_env.je_ret = -1;               \
  62         PL_start_env.je_mustcatch = TRUE;       \
  63         PL_top_env = &PL_start_env;             \
  64     } STMT_END
  65
  66 /*
  67  *   PERL_FLEXIBLE_EXCEPTIONS
  68  *
  69  * All the flexible exceptions code has been removed.
  70  * See the following threads for details:
  71  *
  72  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2004-07/msg00378.html
  73  *
  74  * Joshua's original patches (which weren't applied) and discussion:
  75  *
  76  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01396.html
  77  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01489.html
  78  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01491.html
  79  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01608.html
  80  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg02144.html
  81  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg02998.html
  82  *
  83  * Chip's reworked patch and discussion:
  84  *
  85  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1999-03/msg00520.html
  86  *
  87  * The flaw in these patches (which went unnoticed at the time) was
  88  * that they moved some code that could potentially die() out of the
  89  * region protected by the setjmp()s.  This caused exceptions within
  90  * END blocks and such to not be handled by the correct setjmp().
  91  *
  92  * The original patches that introduces flexible exceptions were:
  93  *
  94  *   http://public.activestate.com/cgi-bin/perlbrowse?patch=3386
  95  *   http://public.activestate.com/cgi-bin/perlbrowse?patch=5162
  96  */
  97
  98 #define dJMPENV         JMPENV cur_env
  99
 100 #define JMPENV_PUSH(v) \
 101     STMT_START {                                                        \
 102         DEBUG_l(Perl_deb(aTHX_ "Setting up jumplevel %p, was %p\n",     \
 103                          &cur_env, PL_top_env));                        \
 104         cur_env.je_prev = PL_top_env;                                   \
 105         OP_REG_TO_MEM;                                                  \
 106         cur_env.je_ret = PerlProc_setjmp(cur_env.je_buf, SCOPE_SAVES_SIGNAL_MASK);              \
 107         OP_MEM_TO_REG;                                                  \
 108         PL_top_env = &cur_env;                                          \
 109         cur_env.je_mustcatch = FALSE;                                   \
 110         (v) = cur_env.je_ret;                                           \
 111     } STMT_END
 112
 113 #define JMPENV_POP \
 114     STMT_START {                                                        \
 115         DEBUG_l(Perl_deb(aTHX_ "popping jumplevel was %p, now %p\n",    \
 116                          PL_top_env, cur_env.je_prev));                 \
 117         PL_top_env = cur_env.je_prev;                                   \
 118     } STMT_END
 119
 120 #define JMPENV_JUMP(v) \
 121     STMT_START {                                                \
 122         OP_REG_TO_MEM;                                          \
 123         if (PL_top_env->je_prev)                                \
 124             PerlProc_longjmp(PL_top_env->je_buf, (v));          \
 125         if ((v) == 2)                                           \
 126             PerlProc_exit(STATUS_EXIT);                         \
 127         PerlIO_printf(PerlIO_stderr(), "panic: top_env\n");     \
 128         PerlProc_exit(1);                                       \
 129     } STMT_END
 130
 131 #define CATCH_GET               (PL_top_env->je_mustcatch)
 132 #define CATCH_SET(v)            (PL_top_env->je_mustcatch = (v))
 133
 134
 135
 136 struct cop {
 137     BASEOP
 138     char *      cop_label;      /* label for this construct */
 139 #ifdef USE_ITHREADS
 140     char *      cop_stashpv;    /* package line was compiled in */
 141     char *      cop_file;       /* file name the following line # is from */
 142 #else
 143     HV *        cop_stash;      /* package line was compiled in */
 144     GV *        cop_filegv;     /* file the following line # is from */
 145 #endif
 146     U32         cop_seq;        /* parse sequence number */
 147     I32         cop_arybase;    /* array base this line was compiled with */
 148     line_t      cop_line;       /* line # of this command */
 149     SV *        cop_warnings;   /* lexical warnings bitmask */
 150     SV *        cop_io;         /* lexical IO defaults */
 151 };
 152
 153 #define Nullcop Null(COP*)
 154
 155 #ifdef USE_ITHREADS
 156 #  define CopFILE(c)            ((c)->cop_file)
 157 #  define CopFILEGV(c)          (CopFILE(c) \
 158                                  ? gv_fetchfile(CopFILE(c)) : Nullgv)
 159
 160 #  ifdef NETWARE
 161 #    define CopFILE_set(c,pv)   ((c)->cop_file = savepv(pv))
 162 #  else
 163 #    define CopFILE_set(c,pv)   ((c)->cop_file = savesharedpv(pv))
 164 #  endif
 165
 166 #  define CopFILESV(c)          (CopFILE(c) \
 167                                  ? GvSV(gv_fetchfile(CopFILE(c))) : Nullsv)
 168 #  define CopFILEAV(c)          (CopFILE(c) \
 169                                  ? GvAV(gv_fetchfile(CopFILE(c))) : NULL)
 170 #  define CopFILEAVx(c)         (assert(CopFILE(c)), \
 171                                    GvAV(gv_fetchfile(CopFILE(c))))
 172 #  define CopSTASHPV(c)         ((c)->cop_stashpv)
 173
 174 #  ifdef NETWARE
 175 #    define CopSTASHPV_set(c,pv)        ((c)->cop_stashpv = ((pv) ? savepv(pv) : Nullch))
 176 #  else
 177 #    define CopSTASHPV_set(c,pv)        ((c)->cop_stashpv = savesharedpv(pv))
 178 #  endif
 179
 180 #  define CopSTASH(c)           (CopSTASHPV(c) \
 181                                  ? gv_stashpv(CopSTASHPV(c),GV_ADD) : NULL)
 182 #  define CopSTASH_set(c,hv)    CopSTASHPV_set(c, (hv) ? HvNAME_get(hv) : Nullch)
 183 #  define CopSTASH_eq(c,hv)     ((hv) && stashpv_hvname_match(c,hv))
 184 #  ifdef NETWARE
 185 #    define CopSTASH_free(c) SAVECOPSTASH_FREE(c)
 186 #    define CopFILE_free(c) SAVECOPFILE_FREE(c)
 187 #  else
 188 #    define CopSTASH_free(c)    PerlMemShared_free(CopSTASHPV(c))
 189 #    define CopFILE_free(c)     (PerlMemShared_free(CopFILE(c)),(CopFILE(c) = Nullch))
 190 #  endif
 191 #else
 192 #  define CopFILEGV(c)          ((c)->cop_filegv)
 193 #  define CopFILEGV_set(c,gv)   ((c)->cop_filegv = (GV*)SvREFCNT_inc(gv))
 194 #  define CopFILE_set(c,pv)     CopFILEGV_set((c), gv_fetchfile(pv))
 195 #  define CopFILESV(c)          (CopFILEGV(c) ? GvSV(CopFILEGV(c)) : Nullsv)
 196 #  define CopFILEAV(c)          (CopFILEGV(c) ? GvAV(CopFILEGV(c)) : NULL)
 197 #  define CopFILEAVx(c)         (assert(CopFILEGV(c)), GvAV(CopFILEGV(c)))
 198 #  define CopFILE(c)            (CopFILESV(c) ? SvPVX(CopFILESV(c)) : Nullch)
 199 #  define CopSTASH(c)           ((c)->cop_stash)
 200 #  define CopSTASH_set(c,hv)    ((c)->cop_stash = (hv))
 201 #  define CopSTASHPV(c)         (CopSTASH(c) ? HvNAME_get(CopSTASH(c)) : Nullch)
 202    /* cop_stash is not refcounted */
 203 #  define CopSTASHPV_set(c,pv)  CopSTASH_set((c), gv_stashpv(pv,GV_ADD))
 204 #  define CopSTASH_eq(c,hv)     (CopSTASH(c) == (hv))
 205 #  define CopSTASH_free(c)
 206 #  define CopFILE_free(c)       (SvREFCNT_dec(CopFILEGV(c)),(CopFILEGV(c) = Nullgv))
 207
 208 #endif /* USE_ITHREADS */
 209
 210 #define CopSTASH_ne(c,hv)       (!CopSTASH_eq(c,hv))
 211 #define CopLINE(c)              ((c)->cop_line)
 212 #define CopLINE_inc(c)          (++CopLINE(c))
 213 #define CopLINE_dec(c)          (--CopLINE(c))
 214 #define CopLINE_set(c,l)        (CopLINE(c) = (l))
 215
 216 /* OutCopFILE() is CopFILE for output (caller, die, warn, etc.) */
 217 #ifdef MACOS_TRADITIONAL
 218 #  define OutCopFILE(c) MacPerl_MPWFileName(CopFILE(c))
 219 #else
 220 #  define OutCopFILE(c) CopFILE(c)
 221 #endif
 222
 223 /*
 224  * Here we have some enormously heavy (or at least ponderous) wizardry.
 225  */
 226
 227 /* subroutine context */
 228 struct block_sub {
 229     CV *        cv;
 230     GV *        gv;
 231     GV *        dfoutgv;
 232     AV *        savearray;
 233     AV *        argarray;
 234     long        olddepth;
 235     U8          hasargs;
 236     U8          lval;           /* XXX merge lval and hasargs? */
 237     PAD         *oldcomppad;
 238     OP *        retop;  /* op to execute on exit from sub */
 239 };
 240
 241 /* base for the next two macros. Don't use directly.
 242  * Note that the refcnt of the cv is incremented twice;  The CX one is
 243  * decremented by LEAVESUB, the other by LEAVE. */
 244
 245 #define PUSHSUB_BASE(cx)                                                \
 246         cx->blk_sub.cv = cv;                                            \
 247         cx->blk_sub.olddepth = CvDEPTH(cv);                             \
 248         cx->blk_sub.hasargs = hasargs;                                  \
 249         cx->blk_sub.retop = Nullop;                                             \
 250         if (!CvDEPTH(cv)) {                                             \
 251             (void)SvREFCNT_inc(cv);                                     \
 252             (void)SvREFCNT_inc(cv);                                     \
 253             SAVEFREESV(cv);                                             \
 254         }
 255
 256
 257 #define PUSHSUB(cx)                                                     \
 258         PUSHSUB_BASE(cx)                                                \
 259         cx->blk_sub.lval = PL_op->op_private &                          \
 260                               (OPpLVAL_INTRO|OPpENTERSUB_INARGS);
 261
 262 /* variant for use by OP_DBSTATE, where op_private holds hint bits */
 263 #define PUSHSUB_DB(cx)                                                  \
 264         PUSHSUB_BASE(cx)                                                \
 265         cx->blk_sub.lval = 0;
 266
 267
 268 #define PUSHFORMAT(cx)                                                  \
 269         cx->blk_sub.cv = cv;                                            \
 270         cx->blk_sub.gv = gv;                                            \
 271         cx->blk_sub.retop = Nullop;                                     \
 272         cx->blk_sub.hasargs = 0;                                        \
 273         cx->blk_sub.dfoutgv = PL_defoutgv;                              \
 274         (void)SvREFCNT_inc(cx->blk_sub.dfoutgv)
 275
 276 #define POP_SAVEARRAY()                                         \
 277     STMT_START {                                                        \
 278         SvREFCNT_dec(GvAV(PL_defgv));                                   \
 279         GvAV(PL_defgv) = cx->blk_sub.savearray;                         \
 280     } STMT_END
 281
 282 /* junk in @_ spells trouble when cloning CVs and in pp_caller(), so don't
 283  * leave any (a fast av_clear(ary), basically) */
 284 #define CLEAR_ARGARRAY(ary) \
 285     STMT_START {                                                        \
 286         AvMAX(ary) += AvARRAY(ary) - AvALLOC(ary);                      \
 287         SvPV_set(ary, (char*)AvALLOC(ary));                             \
 288         AvFILLp(ary) = -1;                                              \
 289     } STMT_END
 290
 291 #define POPSUB(cx,sv)                                                   \
 292     STMT_START {                                                        \
 293         if (cx->blk_sub.hasargs) {                                      \
 294             POP_SAVEARRAY();                                            \
 295             /* abandon @_ if it got reified */                          \
 296             if (AvREAL(cx->blk_sub.argarray)) {                         \
 297                 SSize_t fill = AvFILLp(cx->blk_sub.argarray);           \
 298                 SvREFCNT_dec(cx->blk_sub.argarray);                     \
 299                 cx->blk_sub.argarray = newAV();                         \
 300                 av_extend(cx->blk_sub.argarray, fill);                  \
 301                 AvREIFY_only(cx->blk_sub.argarray);                     \
 302                 CX_CURPAD_SV(cx->blk_sub, 0) = (SV*)cx->blk_sub.argarray;       \
 303             }                                                           \
 304             else {                                                      \
 305                 CLEAR_ARGARRAY(cx->blk_sub.argarray);                   \
 306             }                                                           \
 307         }                                                               \
 308         sv = (SV*)cx->blk_sub.cv;                                       \
 309         if (sv && (CvDEPTH((CV*)sv) = cx->blk_sub.olddepth))            \
 310             sv = Nullsv;                                                \
 311     } STMT_END
 312
 313 #define LEAVESUB(sv)                                                    \
 314     STMT_START {                                                        \
 315         if (sv)                                                         \
 316             SvREFCNT_dec(sv);                                           \
 317     } STMT_END
 318
 319 #define POPFORMAT(cx)                                                   \
 320         setdefout(cx->blk_sub.dfoutgv);                                 \
 321         SvREFCNT_dec(cx->blk_sub.dfoutgv);
 322
 323 /* eval context */
 324 struct block_eval {
 325     I32         old_in_eval;
 326     I32         old_op_type;
 327     SV *        old_namesv;
 328     OP *        old_eval_root;
 329     SV *        cur_text;
 330     CV *        cv;
 331     OP *        retop;  /* op to execute on exit from eval */
 332     JMPENV *    cur_top_env; /* value of PL_top_env when eval CX created */
 333 };
 334
 335 #define PUSHEVAL(cx,n,fgv)                                              \
 336     STMT_START {                                                        \
 337         cx->blk_eval.old_in_eval = PL_in_eval;                          \
 338         cx->blk_eval.old_op_type = PL_op->op_type;                      \
 339         cx->blk_eval.old_namesv = (n ? newSVpv(n,0) : Nullsv);          \
 340         cx->blk_eval.old_eval_root = PL_eval_root;                      \
 341         cx->blk_eval.cur_text = PL_linestr;                             \
 342         cx->blk_eval.cv = Nullcv; /* set by doeval(), as applicable */  \
 343         cx->blk_eval.retop = Nullop;                                    \
 344         cx->blk_eval.cur_top_env = PL_top_env;                          \
 345     } STMT_END
 346
 347 #define POPEVAL(cx)                                                     \
 348     STMT_START {                                                        \
 349         PL_in_eval = cx->blk_eval.old_in_eval;                          \
 350         optype = cx->blk_eval.old_op_type;                              \
 351         PL_eval_root = cx->blk_eval.old_eval_root;                      \
 352         if (cx->blk_eval.old_namesv)                                    \
 353             sv_2mortal(cx->blk_eval.old_namesv);                        \
 354     } STMT_END
 355
 356 /* loop context */
 357 struct block_loop {
 358     char *      label;
 359     I32         resetsp;
 360     OP *        redo_op;
 361     OP *        next_op;
 362     OP *        last_op;
 363 #ifdef USE_ITHREADS
 364     void *      iterdata;
 365     PAD         *oldcomppad;
 366 #else
 367     SV **       itervar;
 368 #endif
 369     SV *        itersave;
 370     SV *        iterlval;
 371     AV *        iterary;
 372     IV          iterix;
 373     IV          itermax;
 374 };
 375
 376 #ifdef USE_ITHREADS
 377 #  define CxITERVAR(c)                                                  \
 378         ((c)->blk_loop.iterdata                                         \
 379          ? (CxPADLOOP(cx)                                               \
 380             ? &CX_CURPAD_SV( (c)->blk_loop,                             \
 381                     INT2PTR(PADOFFSET, (c)->blk_loop.iterdata))         \
 382             : &GvSV((GV*)(c)->blk_loop.iterdata))                       \
 383          : (SV**)NULL)
 384 #  define CX_ITERDATA_SET(cx,idata)                                     \
 385         CX_CURPAD_SAVE(cx->blk_loop);                                   \
 386         if ((cx->blk_loop.iterdata = (idata)))                          \
 387             cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));       \
 388         else                                                            \
 389             cx->blk_loop.itersave = Nullsv;
 390 #else
 391 #  define CxITERVAR(c)          ((c)->blk_loop.itervar)
 392 #  define CX_ITERDATA_SET(cx,ivar)                                      \
 393         if ((cx->blk_loop.itervar = (SV**)(ivar)))                      \
 394             cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));       \
 395         else                                                            \
 396             cx->blk_loop.itersave = Nullsv;
 397 #endif
 398
 399 #define PUSHLOOP(cx, dat, s)                                            \
 400         cx->blk_loop.label = PL_curcop->cop_label;                      \
 401         cx->blk_loop.resetsp = s - PL_stack_base;                       \
 402         cx->blk_loop.redo_op = cLOOP->op_redoop;                        \
 403         cx->blk_loop.next_op = cLOOP->op_nextop;                        \
 404         cx->blk_loop.last_op = cLOOP->op_lastop;                        \
 405         cx->blk_loop.iterlval = Nullsv;                                 \
 406         cx->blk_loop.iterary = NULL;                                    \
 407         cx->blk_loop.iterix = -1;                                       \
 408         CX_ITERDATA_SET(cx,dat);
 409
 410 #define POPLOOP(cx)                                                     \
 411         SvREFCNT_dec(cx->blk_loop.iterlval);                            \
 412         if (CxITERVAR(cx)) {                                            \
 413             if (SvPADMY(cx->blk_loop.itersave)) {                       \
 414                 SV **s_v_p = CxITERVAR(cx);                             \
 415                 sv_2mortal(*s_v_p);                                     \
 416                 *s_v_p = cx->blk_loop.itersave;                         \
 417             }                                                           \
 418             else {                                                      \
 419                 SvREFCNT_dec(cx->blk_loop.itersave);                    \
 420             }                                                           \
 421         }                                                               \
 422         if (cx->blk_loop.iterary && cx->blk_loop.iterary != PL_curstack)\
 423             SvREFCNT_dec(cx->blk_loop.iterary);
 424
 425 /* given/when context */
 426 struct block_givwhen {
 427         OP *leave_op;
 428 };
 429
 430 #define PUSHGIVEN(cx)                                                   \
 431         cx->blk_givwhen.leave_op = cLOGOP->op_other;
 432
 433 #define PUSHWHEN PUSHGIVEN
 434
 435 /* context common to subroutines, evals and loops */
 436 struct block {
 437     I32         blku_oldsp;     /* stack pointer to copy stuff down to */
 438     COP *       blku_oldcop;    /* old curcop pointer */
 439     I32         blku_oldmarksp; /* mark stack index */
 440     I32         blku_oldscopesp;        /* scope stack index */
 441     PMOP *      blku_oldpm;     /* values of pattern match vars */
 442     U8          blku_gimme;     /* is this block running in list context? */
 443
 444     union {
 445         struct block_sub        blku_sub;
 446         struct block_eval       blku_eval;
 447         struct block_loop       blku_loop;
 448         struct block_givwhen    blku_givwhen;
 449     } blk_u;
 450 };
 451 #define blk_oldsp       cx_u.cx_blk.blku_oldsp
 452 #define blk_oldcop      cx_u.cx_blk.blku_oldcop
 453 #define blk_oldmarksp   cx_u.cx_blk.blku_oldmarksp
 454 #define blk_oldscopesp  cx_u.cx_blk.blku_oldscopesp
 455 #define blk_oldpm       cx_u.cx_blk.blku_oldpm
 456 #define blk_gimme       cx_u.cx_blk.blku_gimme
 457 #define blk_sub         cx_u.cx_blk.blk_u.blku_sub
 458 #define blk_eval        cx_u.cx_blk.blk_u.blku_eval
 459 #define blk_loop        cx_u.cx_blk.blk_u.blku_loop
 460 #define blk_givwhen     cx_u.cx_blk.blk_u.blku_givwhen
 461
 462 /* Enter a block. */
 463 #define PUSHBLOCK(cx,t,sp) CXINC, cx = &cxstack[cxstack_ix],            \
 464         cx->cx_type             = t,                                    \
 465         cx->blk_oldsp           = sp - PL_stack_base,                   \
 466         cx->blk_oldcop          = PL_curcop,                            \
 467         cx->blk_oldmarksp       = PL_markstack_ptr - PL_markstack,      \
 468         cx->blk_oldscopesp      = PL_scopestack_ix,                     \
 469         cx->blk_oldpm           = PL_curpm,                             \
 470         cx->blk_gimme           = (U8)gimme;                            \
 471         DEBUG_l( PerlIO_printf(Perl_debug_log, "Entering block %ld, type %s\n", \
 472                     (long)cxstack_ix, PL_block_type[CxTYPE(cx)]); )
 473
 474 /* Exit a block (RETURN and LAST). */
 475 #define POPBLOCK(cx,pm) cx = &cxstack[cxstack_ix--],                    \
 476         newsp            = PL_stack_base + cx->blk_oldsp,               \
 477         PL_curcop        = cx->blk_oldcop,                              \
 478         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
 479         PL_scopestack_ix = cx->blk_oldscopesp,                          \
 480         pm               = cx->blk_oldpm,                               \
 481         gimme            = cx->blk_gimme;                               \
 482         DEBUG_SCOPE("POPBLOCK");                                        \
 483         DEBUG_l( PerlIO_printf(Perl_debug_log, "Leaving block %ld, type %s\n",          \
 484                     (long)cxstack_ix+1,PL_block_type[CxTYPE(cx)]); )
 485
 486 /* Continue a block elsewhere (NEXT and REDO). */
 487 #define TOPBLOCK(cx) cx  = &cxstack[cxstack_ix],                        \
 488         PL_stack_sp      = PL_stack_base + cx->blk_oldsp,               \
 489         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
 490         PL_scopestack_ix = cx->blk_oldscopesp,                          \
 491         PL_curpm         = cx->blk_oldpm;                               \
 492         DEBUG_SCOPE("TOPBLOCK");
 493
 494 /* substitution context */
 495 struct subst {
 496     I32         sbu_iters;
 497     I32         sbu_maxiters;
 498     I32         sbu_rflags;
 499     I32         sbu_oldsave;
 500     bool        sbu_once;
 501     bool        sbu_rxtainted;
 502     char *      sbu_orig;
 503     SV *        sbu_dstr;
 504     SV *        sbu_targ;
 505     char *      sbu_s;
 506     char *      sbu_m;
 507     char *      sbu_strend;
 508     void *      sbu_rxres;
 509     REGEXP *    sbu_rx;
 510 };
 511 #define sb_iters        cx_u.cx_subst.sbu_iters
 512 #define sb_maxiters     cx_u.cx_subst.sbu_maxiters
 513 #define sb_rflags       cx_u.cx_subst.sbu_rflags
 514 #define sb_oldsave      cx_u.cx_subst.sbu_oldsave
 515 #define sb_once         cx_u.cx_subst.sbu_once
 516 #define sb_rxtainted    cx_u.cx_subst.sbu_rxtainted
 517 #define sb_orig         cx_u.cx_subst.sbu_orig
 518 #define sb_dstr         cx_u.cx_subst.sbu_dstr
 519 #define sb_targ         cx_u.cx_subst.sbu_targ
 520 #define sb_s            cx_u.cx_subst.sbu_s
 521 #define sb_m            cx_u.cx_subst.sbu_m
 522 #define sb_strend       cx_u.cx_subst.sbu_strend
 523 #define sb_rxres        cx_u.cx_subst.sbu_rxres
 524 #define sb_rx           cx_u.cx_subst.sbu_rx
 525
 526 #define PUSHSUBST(cx) CXINC, cx = &cxstack[cxstack_ix],                 \
 527         cx->sb_iters            = iters,                                \
 528         cx->sb_maxiters         = maxiters,                             \
 529         cx->sb_rflags           = r_flags,                              \
 530         cx->sb_oldsave          = oldsave,                              \
 531         cx->sb_once             = once,                                 \
 532         cx->sb_rxtainted        = rxtainted,                            \
 533         cx->sb_orig             = orig,                                 \
 534         cx->sb_dstr             = dstr,                                 \
 535         cx->sb_targ             = targ,                                 \
 536         cx->sb_s                = s,                                    \
 537         cx->sb_m                = m,                                    \
 538         cx->sb_strend           = strend,                               \
 539         cx->sb_rxres            = Null(void*),                          \
 540         cx->sb_rx               = rx,                                   \
 541         cx->cx_type             = CXt_SUBST;                            \
 542         rxres_save(&cx->sb_rxres, rx)
 543
 544 #define POPSUBST(cx) cx = &cxstack[cxstack_ix--];                       \
 545         rxres_free(&cx->sb_rxres)
 546
 547 struct context {
 548     U32         cx_type;        /* what kind of context this is */
 549     union {
 550         struct block    cx_blk;
 551         struct subst    cx_subst;
 552     } cx_u;
 553 };
 554
 555 #define CXTYPEMASK      0xff
 556 #define CXt_NULL        0
 557 #define CXt_SUB         1
 558 #define CXt_EVAL        2
 559 #define CXt_LOOP        3
 560 #define CXt_SUBST       4
 561 #define CXt_BLOCK       5
 562 #define CXt_FORMAT      6
 563 #define CXt_GIVEN       7
 564 #define CXt_WHEN        8
 565
 566 /* private flags for CXt_SUB and CXt_NULL */
 567 #define CXp_MULTICALL   0x00000400      /* part of a multicall (so don't
 568                                            tear down context on exit). */
 569
 570 /* private flags for CXt_EVAL */
 571 #define CXp_REAL        0x00000100      /* truly eval'', not a lookalike */
 572 #define CXp_TRYBLOCK    0x00000200      /* eval{}, not eval'' or similar */
 573
 574 /* private flags for CXt_LOOP */
 575 #define CXp_FOREACH     0x00000200      /* a foreach loop */
 576 #define CXp_FOR_DEF     0x00000400      /* foreach using $_ */
 577 #ifdef USE_ITHREADS
 578 #  define CXp_PADVAR    0x00000100      /* itervar lives on pad, iterdata
 579                                            has pad offset; if not set,
 580                                            iterdata holds GV* */
 581 #  define CxPADLOOP(c)  (((c)->cx_type & (CXt_LOOP|CXp_PADVAR))         \
 582                          == (CXt_LOOP|CXp_PADVAR))
 583 #endif
 584
 585 #define CxTYPE(c)       ((c)->cx_type & CXTYPEMASK)
 586 #define CxMULTICALL(c)  (((c)->cx_type & CXp_MULTICALL)                 \
 587                          == CXp_MULTICALL)
 588 #define CxREALEVAL(c)   (((c)->cx_type & (CXt_EVAL|CXp_REAL))           \
 589                          == (CXt_EVAL|CXp_REAL))
 590 #define CxTRYBLOCK(c)   (((c)->cx_type & (CXt_EVAL|CXp_TRYBLOCK))       \
 591                          == (CXt_EVAL|CXp_TRYBLOCK))
 592 #define CxFOREACH(c)    (((c)->cx_type & (CXt_LOOP|CXp_FOREACH))        \
 593                          == (CXt_LOOP|CXp_FOREACH))
 594 #define CxFOREACHDEF(c) (((c)->cx_type & (CXt_LOOP|CXp_FOREACH|CXp_FOR_DEF))\
 595                          == (CXt_LOOP|CXp_FOREACH|CXp_FOR_DEF))
 596
 597 #define CXINC (cxstack_ix < cxstack_max ? ++cxstack_ix : (cxstack_ix = cxinc()))
 598
 599 /*
 600 =head1 "Gimme" Values
 601 */
 602
 603 /*
 604 =for apidoc AmU||G_SCALAR
 605 Used to indicate scalar context.  See C<GIMME_V>, C<GIMME>, and
 606 L<perlcall>.
 607
 608 =for apidoc AmU||G_ARRAY
 609 Used to indicate list context.  See C<GIMME_V>, C<GIMME> and
 610 L<perlcall>.
 611
 612 =for apidoc AmU||G_VOID
 613 Used to indicate void context.  See C<GIMME_V> and L<perlcall>.
 614
 615 =for apidoc AmU||G_DISCARD
 616 Indicates that arguments returned from a callback should be discarded.  See
 617 L<perlcall>.
 618
 619 =for apidoc AmU||G_EVAL
 620
 621 Used to force a Perl C<eval> wrapper around a callback.  See
 622 L<perlcall>.
 623
 624 =for apidoc AmU||G_NOARGS
 625
 626 Indicates that no arguments are being sent to a callback.  See
 627 L<perlcall>.
 628
 629 =cut
 630 */
 631
 632 #define G_SCALAR        0
 633 #define G_ARRAY         1
 634 #define G_VOID          128     /* skip this bit when adding flags below */
 635
 636 /* extra flags for Perl_call_* routines */
 637 #define G_DISCARD       2       /* Call FREETMPS. */
 638 #define G_EVAL          4       /* Assume eval {} around subroutine call. */
 639 #define G_NOARGS        8       /* Don't construct a @_ array. */
 640 #define G_KEEPERR      16       /* Append errors to $@, don't overwrite it */
 641 #define G_NODEBUG      32       /* Disable debugging at toplevel.  */
 642 #define G_METHOD       64       /* Calling method. */
 643
 644 /* flag bits for PL_in_eval */
 645 #define EVAL_NULL       0       /* not in an eval */
 646 #define EVAL_INEVAL     1       /* some enclosing scope is an eval */
 647 #define EVAL_WARNONLY   2       /* used by yywarn() when calling yyerror() */
 648 #define EVAL_KEEPERR    4       /* set by Perl_call_sv if G_KEEPERR */
 649 #define EVAL_INREQUIRE  8       /* The code is being required. */
 650
 651 /* Support for switching (stack and block) contexts.
 652  * This ensures magic doesn't invalidate local stack and cx pointers.
 653  */
 654
 655 #define PERLSI_UNKNOWN          -1
 656 #define PERLSI_UNDEF            0
 657 #define PERLSI_MAIN             1
 658 #define PERLSI_MAGIC            2
 659 #define PERLSI_SORT             3
 660 #define PERLSI_SIGNAL           4
 661 #define PERLSI_OVERLOAD         5
 662 #define PERLSI_DESTROY          6
 663 #define PERLSI_WARNHOOK         7
 664 #define PERLSI_DIEHOOK          8
 665 #define PERLSI_REQUIRE          9
 666
 667 struct stackinfo {
 668     AV *                si_stack;       /* stack for current runlevel */
 669     PERL_CONTEXT *      si_cxstack;     /* context stack for runlevel */
 670     I32                 si_cxix;        /* current context index */
 671     I32                 si_cxmax;       /* maximum allocated index */
 672     I32                 si_type;        /* type of runlevel */
 673     struct stackinfo *  si_prev;
 674     struct stackinfo *  si_next;
 675     I32                 si_markoff;     /* offset where markstack begins for us.
 676                                          * currently used only with DEBUGGING,
 677                                          * but not #ifdef-ed for bincompat */
 678 };
 679
 680 typedef struct stackinfo PERL_SI;
 681
 682 #define cxstack         (PL_curstackinfo->si_cxstack)
 683 #define cxstack_ix      (PL_curstackinfo->si_cxix)
 684 #define cxstack_max     (PL_curstackinfo->si_cxmax)
 685
 686 #ifdef DEBUGGING
 687 #  define       SET_MARK_OFFSET \
 688     PL_curstackinfo->si_markoff = PL_markstack_ptr - PL_markstack
 689 #else
 690 #  define       SET_MARK_OFFSET NOOP
 691 #endif
 692
 693 #define PUSHSTACKi(type) \
 694     STMT_START {                                                        \
 695         PERL_SI *next = PL_curstackinfo->si_next;                       \
 696         if (!next) {                                                    \
 697             next = new_stackinfo(32, 2048/sizeof(PERL_CONTEXT) - 1);    \
 698             next->si_prev = PL_curstackinfo;                            \
 699             PL_curstackinfo->si_next = next;                            \
 700         }                                                               \
 701         next->si_type = type;                                           \
 702         next->si_cxix = -1;                                             \
 703         AvFILLp(next->si_stack) = 0;                                    \
 704         SWITCHSTACK(PL_curstack,next->si_stack);                        \
 705         PL_curstackinfo = next;                                         \
 706         SET_MARK_OFFSET;                                                \
 707     } STMT_END
 708
 709 #define PUSHSTACK PUSHSTACKi(PERLSI_UNKNOWN)
 710
 711 /* POPSTACK works with PL_stack_sp, so it may need to be bracketed by
 712  * PUTBACK/SPAGAIN to flush/refresh any local SP that may be active */
 713 #define POPSTACK \
 714     STMT_START {                                                        \
 715         dSP;                                                            \
 716         PERL_SI * const prev = PL_curstackinfo->si_prev;                \
 717         if (!prev) {                                                    \
 718             PerlIO_printf(Perl_error_log, "panic: POPSTACK\n");         \
 719             my_exit(1);                                                 \
 720         }                                                               \
 721         SWITCHSTACK(PL_curstack,prev->si_stack);                        \
 722         /* don't free prev here, free them all at the END{} */          \
 723         PL_curstackinfo = prev;                                         \
 724     } STMT_END
 725
 726 #define POPSTACK_TO(s) \
 727     STMT_START {                                                        \
 728         while (PL_curstack != s) {                                      \
 729             dounwind(-1);                                               \
 730             POPSTACK;                                                   \
 731         }                                                               \
 732     } STMT_END
 733
 734 #define IN_PERL_COMPILETIME     (PL_curcop == &PL_compiling)
 735 #define IN_PERL_RUNTIME         (PL_curcop != &PL_compiling)
 736
 737 /*
 738 =head1 Multicall Functions
 739
 740 =for apidoc Ams||dMULTICALL
 741 Declare local variables for a multicall. See L<perlcall/Lightweight Callbacks>.
 742
 743 =for apidoc Ams||PUSH_MULTICALL
 744 Opening bracket for a lightweight callback.
 745 See L<perlcall/Lightweight Callbacks>.
 746
 747 =for apidoc Ams||MULTICALL
 748 Make a lightweight callback. See L<perlcall/Lightweight Callbacks>.
 749
 750 =for apidoc Ams||POP_MULTICALL
 751 Closing bracket for a lightweight callback.
 752 See L<perlcall/Lightweight Callbacks>.
 753
 754 =cut
 755 */
 756
 757 #define dMULTICALL \
 758     SV **newsp;                 /* set by POPBLOCK */                   \
 759     PERL_CONTEXT *cx;                                                   \
 760     CV *multicall_cv;                                                   \
 761     OP *multicall_cop;                                                  \
 762     bool multicall_oldcatch;                                            \
 763     U8 hasargs = 0              /* used by PUSHSUB */
 764
 765 #define PUSH_MULTICALL(the_cv) \
 766     STMT_START {                                                        \
 767         CV * const _nOnclAshIngNamE_ = the_cv;                          \
 768         CV * const cv = _nOnclAshIngNamE_;                              \
 769         AV * const padlist = CvPADLIST(cv);                             \
 770         ENTER;                                                          \
 771         multicall_oldcatch = CATCH_GET;                                 \
 772         SAVETMPS; SAVEVPTR(PL_op);                                      \
 773         CATCH_SET(TRUE);                                                \
 774         PUSHBLOCK(cx, CXt_SUB|CXp_MULTICALL, PL_stack_sp);              \
 775         PUSHSUB(cx);                                                    \
 776         if (++CvDEPTH(cv) >= 2) {                                       \
 777             PERL_STACK_OVERFLOW_CHECK();                                \
 778             Perl_pad_push(aTHX_ padlist, CvDEPTH(cv));                  \
 779         }                                                               \
 780         SAVECOMPPAD();                                                  \
 781         PAD_SET_CUR_NOSAVE(padlist, CvDEPTH(cv));                       \
 782         multicall_cv = cv;                                              \
 783         multicall_cop = CvSTART(cv);                                    \
 784     } STMT_END
 785
 786 #define MULTICALL \
 787     STMT_START {                                                        \
 788         PL_op = multicall_cop;                                          \
 789         CALLRUNOPS(aTHX);                                               \
 790     } STMT_END
 791
 792 #define POP_MULTICALL \
 793     STMT_START {                                                        \
 794         LEAVESUB(multicall_cv);                                         \
 795         CvDEPTH(multicall_cv)--;                                        \
 796         POPBLOCK(cx,PL_curpm);                                          \
 797         CATCH_SET(multicall_oldcatch);                                  \
 798         LEAVE;                                                          \
 799     } STMT_END