cop.h

   1 /*    cop.h
   2  *
   3  *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
   4  *    2000, 2001, 2002, 2003, 2004, 2005, 2006 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     /* compile time state of %^H.  See the comment in op.c for how this is
 152        used to recreate a hash to return from caller.  */
 153     struct refcounted_he * cop_hints;
 154 };
 155
 156 #ifdef USE_ITHREADS
 157 #  define CopFILE(c)            ((c)->cop_file)
 158 #  define CopFILEGV(c)          (CopFILE(c) \
 159                                  ? gv_fetchfile(CopFILE(c)) : NULL)
 160
 161 #  ifdef NETWARE
 162 #    define CopFILE_set(c,pv)   ((c)->cop_file = savepv(pv))
 163 #  else
 164 #    define CopFILE_set(c,pv)   ((c)->cop_file = savesharedpv(pv))
 165 #  endif
 166
 167 #  define CopFILESV(c)          (CopFILE(c) \
 168                                  ? GvSV(gv_fetchfile(CopFILE(c))) : NULL)
 169 #  define CopFILEAV(c)          (CopFILE(c) \
 170                                  ? GvAV(gv_fetchfile(CopFILE(c))) : NULL)
 171 #  ifdef DEBUGGING
 172 #    define CopFILEAVx(c)       (assert(CopFILE(c)), \
 173                                    GvAV(gv_fetchfile(CopFILE(c))))
 174 #  else
 175 #    define CopFILEAVx(c)       (GvAV(gv_fetchfile(CopFILE(c))))
 176 #  endif
 177 #  define CopSTASHPV(c)         ((c)->cop_stashpv)
 178
 179 #  ifdef NETWARE
 180 #    define CopSTASHPV_set(c,pv)        ((c)->cop_stashpv = ((pv) ? savepv(pv) : NULL))
 181 #  else
 182 #    define CopSTASHPV_set(c,pv)        ((c)->cop_stashpv = savesharedpv(pv))
 183 #  endif
 184
 185 #  define CopSTASH(c)           (CopSTASHPV(c) \
 186                                  ? gv_stashpv(CopSTASHPV(c),GV_ADD) : NULL)
 187 #  define CopSTASH_set(c,hv)    CopSTASHPV_set(c, (hv) ? HvNAME_get(hv) : NULL)
 188 #  define CopSTASH_eq(c,hv)     ((hv) && stashpv_hvname_match(c,hv))
 189 #  ifdef NETWARE
 190 #    define CopSTASH_free(c) SAVECOPSTASH_FREE(c)
 191 #    define CopFILE_free(c) SAVECOPFILE_FREE(c)
 192 #  else
 193 #    define CopSTASH_free(c)    PerlMemShared_free(CopSTASHPV(c))
 194 #    define CopFILE_free(c)     (PerlMemShared_free(CopFILE(c)),(CopFILE(c) = NULL))
 195 #  endif
 196 #else
 197 #  define CopFILEGV(c)          ((c)->cop_filegv)
 198 #  define CopFILEGV_set(c,gv)   ((c)->cop_filegv = (GV*)SvREFCNT_inc(gv))
 199 #  define CopFILE_set(c,pv)     CopFILEGV_set((c), gv_fetchfile(pv))
 200 #  define CopFILESV(c)          (CopFILEGV(c) ? GvSV(CopFILEGV(c)) : NULL)
 201 #  define CopFILEAV(c)          (CopFILEGV(c) ? GvAV(CopFILEGV(c)) : NULL)
 202 #  ifdef DEBUGGING
 203 #    define CopFILEAVx(c)       (assert(CopFILEGV(c)), GvAV(CopFILEGV(c)))
 204 #  else
 205 #    define CopFILEAVx(c)       (GvAV(CopFILEGV(c)))
 206 # endif
 207 #  define CopFILE(c)            (CopFILESV(c) ? SvPVX(CopFILESV(c)) : NULL)
 208 #  define CopSTASH(c)           ((c)->cop_stash)
 209 #  define CopSTASH_set(c,hv)    ((c)->cop_stash = (hv))
 210 #  define CopSTASHPV(c)         (CopSTASH(c) ? HvNAME_get(CopSTASH(c)) : NULL)
 211    /* cop_stash is not refcounted */
 212 #  define CopSTASHPV_set(c,pv)  CopSTASH_set((c), gv_stashpv(pv,GV_ADD))
 213 #  define CopSTASH_eq(c,hv)     (CopSTASH(c) == (hv))
 214 #  define CopSTASH_free(c)
 215 #  define CopFILE_free(c)       (SvREFCNT_dec(CopFILEGV(c)),(CopFILEGV(c) = NULL))
 216
 217 #endif /* USE_ITHREADS */
 218
 219 #define CopSTASH_ne(c,hv)       (!CopSTASH_eq(c,hv))
 220 #define CopLINE(c)              ((c)->cop_line)
 221 #define CopLINE_inc(c)          (++CopLINE(c))
 222 #define CopLINE_dec(c)          (--CopLINE(c))
 223 #define CopLINE_set(c,l)        (CopLINE(c) = (l))
 224
 225 /* OutCopFILE() is CopFILE for output (caller, die, warn, etc.) */
 226 #ifdef MACOS_TRADITIONAL
 227 #  define OutCopFILE(c) MacPerl_MPWFileName(CopFILE(c))
 228 #else
 229 #  define OutCopFILE(c) CopFILE(c)
 230 #endif
 231
 232 /* CopARYBASE is likely to be removed soon.  */
 233 #define CopARYBASE(c)           ((c)->cop_arybase)
 234 #define CopARYBASE_get(c)       ((c)->cop_arybase + 0)
 235 #define CopARYBASE_set(c, b)    STMT_START { (c)->cop_arybase = (b); } STMT_END
 236
 237 /*
 238  * Here we have some enormously heavy (or at least ponderous) wizardry.
 239  */
 240
 241 /* subroutine context */
 242 struct block_sub {
 243     CV *        cv;
 244     GV *        gv;
 245     GV *        dfoutgv;
 246     AV *        savearray;
 247     AV *        argarray;
 248     I32         olddepth;
 249     U8          hasargs;
 250     U8          lval;           /* XXX merge lval and hasargs? */
 251     PAD         *oldcomppad;
 252     OP *        retop;  /* op to execute on exit from sub */
 253 };
 254
 255 /* base for the next two macros. Don't use directly.
 256  * Note that the refcnt of the cv is incremented twice;  The CX one is
 257  * decremented by LEAVESUB, the other by LEAVE. */
 258
 259 #define PUSHSUB_BASE(cx)                                                \
 260         cx->blk_sub.cv = cv;                                            \
 261         cx->blk_sub.olddepth = CvDEPTH(cv);                             \
 262         cx->blk_sub.hasargs = hasargs;                                  \
 263         cx->blk_sub.retop = NULL;                                       \
 264         if (!CvDEPTH(cv)) {                                             \
 265             SvREFCNT_inc_void(cv);                                      \
 266             SvREFCNT_inc_void(cv);                                      \
 267             SAVEFREESV(cv);                                             \
 268         }
 269
 270
 271 #define PUSHSUB(cx)                                                     \
 272         PUSHSUB_BASE(cx)                                                \
 273         cx->blk_sub.lval = PL_op->op_private &                          \
 274                               (OPpLVAL_INTRO|OPpENTERSUB_INARGS);
 275
 276 /* variant for use by OP_DBSTATE, where op_private holds hint bits */
 277 #define PUSHSUB_DB(cx)                                                  \
 278         PUSHSUB_BASE(cx)                                                \
 279         cx->blk_sub.lval = 0;
 280
 281
 282 #define PUSHFORMAT(cx)                                                  \
 283         cx->blk_sub.cv = cv;                                            \
 284         cx->blk_sub.gv = gv;                                            \
 285         cx->blk_sub.retop = NULL;                                       \
 286         cx->blk_sub.hasargs = 0;                                        \
 287         cx->blk_sub.dfoutgv = PL_defoutgv;                              \
 288         SvREFCNT_inc_void(cx->blk_sub.dfoutgv)
 289
 290 #define POP_SAVEARRAY()                                         \
 291     STMT_START {                                                        \
 292         SvREFCNT_dec(GvAV(PL_defgv));                                   \
 293         GvAV(PL_defgv) = cx->blk_sub.savearray;                         \
 294     } STMT_END
 295
 296 /* junk in @_ spells trouble when cloning CVs and in pp_caller(), so don't
 297  * leave any (a fast av_clear(ary), basically) */
 298 #define CLEAR_ARGARRAY(ary) \
 299     STMT_START {                                                        \
 300         AvMAX(ary) += AvARRAY(ary) - AvALLOC(ary);                      \
 301         SvPV_set(ary, (char*)AvALLOC(ary));                             \
 302         AvFILLp(ary) = -1;                                              \
 303     } STMT_END
 304
 305 #define POPSUB(cx,sv)                                                   \
 306     STMT_START {                                                        \
 307         if (cx->blk_sub.hasargs) {                                      \
 308             POP_SAVEARRAY();                                            \
 309             /* abandon @_ if it got reified */                          \
 310             if (AvREAL(cx->blk_sub.argarray)) {                         \
 311                 SSize_t fill = AvFILLp(cx->blk_sub.argarray);           \
 312                 SvREFCNT_dec(cx->blk_sub.argarray);                     \
 313                 cx->blk_sub.argarray = newAV();                         \
 314                 av_extend(cx->blk_sub.argarray, fill);                  \
 315                 AvREIFY_only(cx->blk_sub.argarray);                     \
 316                 CX_CURPAD_SV(cx->blk_sub, 0) = (SV*)cx->blk_sub.argarray;       \
 317             }                                                           \
 318             else {                                                      \
 319                 CLEAR_ARGARRAY(cx->blk_sub.argarray);                   \
 320             }                                                           \
 321         }                                                               \
 322         sv = (SV*)cx->blk_sub.cv;                                       \
 323         if (sv && (CvDEPTH((CV*)sv) = cx->blk_sub.olddepth))            \
 324             sv = NULL;                                          \
 325     } STMT_END
 326
 327 #define LEAVESUB(sv)                                                    \
 328     STMT_START {                                                        \
 329         if (sv)                                                         \
 330             SvREFCNT_dec(sv);                                           \
 331     } STMT_END
 332
 333 #define POPFORMAT(cx)                                                   \
 334         setdefout(cx->blk_sub.dfoutgv);                                 \
 335         SvREFCNT_dec(cx->blk_sub.dfoutgv);
 336
 337 /* eval context */
 338 struct block_eval {
 339     I32         old_in_eval;
 340     I32         old_op_type;
 341     SV *        old_namesv;
 342     OP *        old_eval_root;
 343     SV *        cur_text;
 344     CV *        cv;
 345     OP *        retop;  /* op to execute on exit from eval */
 346     JMPENV *    cur_top_env; /* value of PL_top_env when eval CX created */
 347 };
 348
 349 #define PUSHEVAL(cx,n,fgv)                                              \
 350     STMT_START {                                                        \
 351         cx->blk_eval.old_in_eval = PL_in_eval;                          \
 352         cx->blk_eval.old_op_type = PL_op->op_type;                      \
 353         cx->blk_eval.old_namesv = (n ? newSVpv(n,0) : NULL);            \
 354         cx->blk_eval.old_eval_root = PL_eval_root;                      \
 355         cx->blk_eval.cur_text = PL_linestr;                             \
 356         cx->blk_eval.cv = NULL; /* set by doeval(), as applicable */    \
 357         cx->blk_eval.retop = NULL;                                      \
 358         cx->blk_eval.cur_top_env = PL_top_env;                          \
 359     } STMT_END
 360
 361 #define POPEVAL(cx)                                                     \
 362     STMT_START {                                                        \
 363         PL_in_eval = cx->blk_eval.old_in_eval;                          \
 364         optype = cx->blk_eval.old_op_type;                              \
 365         PL_eval_root = cx->blk_eval.old_eval_root;                      \
 366         if (cx->blk_eval.old_namesv)                                    \
 367             sv_2mortal(cx->blk_eval.old_namesv);                        \
 368     } STMT_END
 369
 370 /* loop context */
 371 struct block_loop {
 372     char *      label;
 373     I32         resetsp;
 374     OP *        redo_op;
 375     OP *        next_op;
 376     OP *        last_op;
 377 #ifdef USE_ITHREADS
 378     void *      iterdata;
 379     PAD         *oldcomppad;
 380 #else
 381     SV **       itervar;
 382 #endif
 383     SV *        itersave;
 384     SV *        iterlval;
 385     AV *        iterary;
 386     IV          iterix;
 387     IV          itermax;
 388 };
 389
 390 #ifdef USE_ITHREADS
 391 #  define CxITERVAR(c)                                                  \
 392         ((c)->blk_loop.iterdata                                         \
 393          ? (CxPADLOOP(cx)                                               \
 394             ? &CX_CURPAD_SV( (c)->blk_loop,                             \
 395                     INT2PTR(PADOFFSET, (c)->blk_loop.iterdata))         \
 396             : &GvSV((GV*)(c)->blk_loop.iterdata))                       \
 397          : (SV**)NULL)
 398 #  define CX_ITERDATA_SET(cx,idata)                                     \
 399         CX_CURPAD_SAVE(cx->blk_loop);                                   \
 400         if ((cx->blk_loop.iterdata = (idata)))                          \
 401             cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));       \
 402         else                                                            \
 403             cx->blk_loop.itersave = NULL;
 404 #else
 405 #  define CxITERVAR(c)          ((c)->blk_loop.itervar)
 406 #  define CX_ITERDATA_SET(cx,ivar)                                      \
 407         if ((cx->blk_loop.itervar = (SV**)(ivar)))                      \
 408             cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));       \
 409         else                                                            \
 410             cx->blk_loop.itersave = NULL;
 411 #endif
 412
 413 #define PUSHLOOP(cx, dat, s)                                            \
 414         cx->blk_loop.label = PL_curcop->cop_label;                      \
 415         cx->blk_loop.resetsp = s - PL_stack_base;                       \
 416         cx->blk_loop.redo_op = cLOOP->op_redoop;                        \
 417         cx->blk_loop.next_op = cLOOP->op_nextop;                        \
 418         cx->blk_loop.last_op = cLOOP->op_lastop;                        \
 419         cx->blk_loop.iterlval = NULL;                                   \
 420         cx->blk_loop.iterary = NULL;                                    \
 421         cx->blk_loop.iterix = -1;                                       \
 422         CX_ITERDATA_SET(cx,dat);
 423
 424 #define POPLOOP(cx)                                                     \
 425         SvREFCNT_dec(cx->blk_loop.iterlval);                            \
 426         if (CxITERVAR(cx)) {                                            \
 427             if (SvPADMY(cx->blk_loop.itersave)) {                       \
 428                 SV ** const s_v_p = CxITERVAR(cx);                      \
 429                 sv_2mortal(*s_v_p);                                     \
 430                 *s_v_p = cx->blk_loop.itersave;                         \
 431             }                                                           \
 432             else {                                                      \
 433                 SvREFCNT_dec(cx->blk_loop.itersave);                    \
 434             }                                                           \
 435         }                                                               \
 436         if (cx->blk_loop.iterary && cx->blk_loop.iterary != PL_curstack)\
 437             SvREFCNT_dec(cx->blk_loop.iterary);
 438
 439 /* given/when context */
 440 struct block_givwhen {
 441         OP *leave_op;
 442 };
 443
 444 #define PUSHGIVEN(cx)                                                   \
 445         cx->blk_givwhen.leave_op = cLOGOP->op_other;
 446
 447 #define PUSHWHEN PUSHGIVEN
 448
 449 /* context common to subroutines, evals and loops */
 450 struct block {
 451     I32         blku_oldsp;     /* stack pointer to copy stuff down to */
 452     COP *       blku_oldcop;    /* old curcop pointer */
 453     I32         blku_oldmarksp; /* mark stack index */
 454     I32         blku_oldscopesp;        /* scope stack index */
 455     PMOP *      blku_oldpm;     /* values of pattern match vars */
 456     U8          blku_gimme;     /* is this block running in list context? */
 457
 458     union {
 459         struct block_sub        blku_sub;
 460         struct block_eval       blku_eval;
 461         struct block_loop       blku_loop;
 462         struct block_givwhen    blku_givwhen;
 463     } blk_u;
 464 };
 465 #define blk_oldsp       cx_u.cx_blk.blku_oldsp
 466 #define blk_oldcop      cx_u.cx_blk.blku_oldcop
 467 #define blk_oldmarksp   cx_u.cx_blk.blku_oldmarksp
 468 #define blk_oldscopesp  cx_u.cx_blk.blku_oldscopesp
 469 #define blk_oldpm       cx_u.cx_blk.blku_oldpm
 470 #define blk_gimme       cx_u.cx_blk.blku_gimme
 471 #define blk_sub         cx_u.cx_blk.blk_u.blku_sub
 472 #define blk_eval        cx_u.cx_blk.blk_u.blku_eval
 473 #define blk_loop        cx_u.cx_blk.blk_u.blku_loop
 474 #define blk_givwhen     cx_u.cx_blk.blk_u.blku_givwhen
 475
 476 /* Enter a block. */
 477 #define PUSHBLOCK(cx,t,sp) CXINC, cx = &cxstack[cxstack_ix],            \
 478         cx->cx_type             = t,                                    \
 479         cx->blk_oldsp           = sp - PL_stack_base,                   \
 480         cx->blk_oldcop          = PL_curcop,                            \
 481         cx->blk_oldmarksp       = PL_markstack_ptr - PL_markstack,      \
 482         cx->blk_oldscopesp      = PL_scopestack_ix,                     \
 483         cx->blk_oldpm           = PL_curpm,                             \
 484         cx->blk_gimme           = (U8)gimme;                            \
 485         DEBUG_l( PerlIO_printf(Perl_debug_log, "Entering block %ld, type %s\n", \
 486                     (long)cxstack_ix, PL_block_type[CxTYPE(cx)]); )
 487
 488 /* Exit a block (RETURN and LAST). */
 489 #define POPBLOCK(cx,pm) cx = &cxstack[cxstack_ix--],                    \
 490         newsp            = PL_stack_base + cx->blk_oldsp,               \
 491         PL_curcop        = cx->blk_oldcop,                              \
 492         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
 493         PL_scopestack_ix = cx->blk_oldscopesp,                          \
 494         pm               = cx->blk_oldpm,                               \
 495         gimme            = cx->blk_gimme;                               \
 496         DEBUG_SCOPE("POPBLOCK");                                        \
 497         DEBUG_l( PerlIO_printf(Perl_debug_log, "Leaving block %ld, type %s\n",          \
 498                     (long)cxstack_ix+1,PL_block_type[CxTYPE(cx)]); )
 499
 500 /* Continue a block elsewhere (NEXT and REDO). */
 501 #define TOPBLOCK(cx) cx  = &cxstack[cxstack_ix],                        \
 502         PL_stack_sp      = PL_stack_base + cx->blk_oldsp,               \
 503         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
 504         PL_scopestack_ix = cx->blk_oldscopesp,                          \
 505         PL_curpm         = cx->blk_oldpm;                               \
 506         DEBUG_SCOPE("TOPBLOCK");
 507
 508 /* substitution context */
 509 struct subst {
 510     I32         sbu_iters;
 511     I32         sbu_maxiters;
 512     I32         sbu_rflags;
 513     I32         sbu_oldsave;
 514     bool        sbu_once;
 515     bool        sbu_rxtainted;
 516     char *      sbu_orig;
 517     SV *        sbu_dstr;
 518     SV *        sbu_targ;
 519     char *      sbu_s;
 520     char *      sbu_m;
 521     char *      sbu_strend;
 522     void *      sbu_rxres;
 523     REGEXP *    sbu_rx;
 524 };
 525 #define sb_iters        cx_u.cx_subst.sbu_iters
 526 #define sb_maxiters     cx_u.cx_subst.sbu_maxiters
 527 #define sb_rflags       cx_u.cx_subst.sbu_rflags
 528 #define sb_oldsave      cx_u.cx_subst.sbu_oldsave
 529 #define sb_once         cx_u.cx_subst.sbu_once
 530 #define sb_rxtainted    cx_u.cx_subst.sbu_rxtainted
 531 #define sb_orig         cx_u.cx_subst.sbu_orig
 532 #define sb_dstr         cx_u.cx_subst.sbu_dstr
 533 #define sb_targ         cx_u.cx_subst.sbu_targ
 534 #define sb_s            cx_u.cx_subst.sbu_s
 535 #define sb_m            cx_u.cx_subst.sbu_m
 536 #define sb_strend       cx_u.cx_subst.sbu_strend
 537 #define sb_rxres        cx_u.cx_subst.sbu_rxres
 538 #define sb_rx           cx_u.cx_subst.sbu_rx
 539
 540 #define PUSHSUBST(cx) CXINC, cx = &cxstack[cxstack_ix],                 \
 541         cx->sb_iters            = iters,                                \
 542         cx->sb_maxiters         = maxiters,                             \
 543         cx->sb_rflags           = r_flags,                              \
 544         cx->sb_oldsave          = oldsave,                              \
 545         cx->sb_once             = once,                                 \
 546         cx->sb_rxtainted        = rxtainted,                            \
 547         cx->sb_orig             = orig,                                 \
 548         cx->sb_dstr             = dstr,                                 \
 549         cx->sb_targ             = targ,                                 \
 550         cx->sb_s                = s,                                    \
 551         cx->sb_m                = m,                                    \
 552         cx->sb_strend           = strend,                               \
 553         cx->sb_rxres            = NULL,                                 \
 554         cx->sb_rx               = rx,                                   \
 555         cx->cx_type             = CXt_SUBST;                            \
 556         rxres_save(&cx->sb_rxres, rx)
 557
 558 #define POPSUBST(cx) cx = &cxstack[cxstack_ix--];                       \
 559         rxres_free(&cx->sb_rxres)
 560
 561 struct context {
 562     U32         cx_type;        /* what kind of context this is */
 563     union {
 564         struct block    cx_blk;
 565         struct subst    cx_subst;
 566     } cx_u;
 567 };
 568
 569 #define CXTYPEMASK      0xff
 570 #define CXt_NULL        0
 571 #define CXt_SUB         1
 572 #define CXt_EVAL        2
 573 #define CXt_LOOP        3
 574 #define CXt_SUBST       4
 575 #define CXt_BLOCK       5
 576 #define CXt_FORMAT      6
 577 #define CXt_GIVEN       7
 578 #define CXt_WHEN        8
 579
 580 /* private flags for CXt_SUB and CXt_NULL */
 581 #define CXp_MULTICALL   0x00000400      /* part of a multicall (so don't
 582                                            tear down context on exit). */
 583
 584 /* private flags for CXt_EVAL */
 585 #define CXp_REAL        0x00000100      /* truly eval'', not a lookalike */
 586 #define CXp_TRYBLOCK    0x00000200      /* eval{}, not eval'' or similar */
 587
 588 /* private flags for CXt_LOOP */
 589 #define CXp_FOREACH     0x00000200      /* a foreach loop */
 590 #define CXp_FOR_DEF     0x00000400      /* foreach using $_ */
 591 #ifdef USE_ITHREADS
 592 #  define CXp_PADVAR    0x00000100      /* itervar lives on pad, iterdata
 593                                            has pad offset; if not set,
 594                                            iterdata holds GV* */
 595 #  define CxPADLOOP(c)  (((c)->cx_type & (CXt_LOOP|CXp_PADVAR))         \
 596                          == (CXt_LOOP|CXp_PADVAR))
 597 #endif
 598
 599 #define CxTYPE(c)       ((c)->cx_type & CXTYPEMASK)
 600 #define CxMULTICALL(c)  (((c)->cx_type & CXp_MULTICALL)                 \
 601                          == CXp_MULTICALL)
 602 #define CxREALEVAL(c)   (((c)->cx_type & (CXt_EVAL|CXp_REAL))           \
 603                          == (CXt_EVAL|CXp_REAL))
 604 #define CxTRYBLOCK(c)   (((c)->cx_type & (CXt_EVAL|CXp_TRYBLOCK))       \
 605                          == (CXt_EVAL|CXp_TRYBLOCK))
 606 #define CxFOREACH(c)    (((c)->cx_type & (CXt_LOOP|CXp_FOREACH))        \
 607                          == (CXt_LOOP|CXp_FOREACH))
 608 #define CxFOREACHDEF(c) (((c)->cx_type & (CXt_LOOP|CXp_FOREACH|CXp_FOR_DEF))\
 609                          == (CXt_LOOP|CXp_FOREACH|CXp_FOR_DEF))
 610
 611 #define CXINC (cxstack_ix < cxstack_max ? ++cxstack_ix : (cxstack_ix = cxinc()))
 612
 613 /*
 614 =head1 "Gimme" Values
 615 */
 616
 617 /*
 618 =for apidoc AmU||G_SCALAR
 619 Used to indicate scalar context.  See C<GIMME_V>, C<GIMME>, and
 620 L<perlcall>.
 621
 622 =for apidoc AmU||G_ARRAY
 623 Used to indicate list context.  See C<GIMME_V>, C<GIMME> and
 624 L<perlcall>.
 625
 626 =for apidoc AmU||G_VOID
 627 Used to indicate void context.  See C<GIMME_V> and L<perlcall>.
 628
 629 =for apidoc AmU||G_DISCARD
 630 Indicates that arguments returned from a callback should be discarded.  See
 631 L<perlcall>.
 632
 633 =for apidoc AmU||G_EVAL
 634
 635 Used to force a Perl C<eval> wrapper around a callback.  See
 636 L<perlcall>.
 637
 638 =for apidoc AmU||G_NOARGS
 639
 640 Indicates that no arguments are being sent to a callback.  See
 641 L<perlcall>.
 642
 643 =cut
 644 */
 645
 646 #define G_SCALAR        0
 647 #define G_ARRAY         1
 648 #define G_VOID          128     /* skip this bit when adding flags below */
 649
 650 /* extra flags for Perl_call_* routines */
 651 #define G_DISCARD       2       /* Call FREETMPS. */
 652 #define G_EVAL          4       /* Assume eval {} around subroutine call. */
 653 #define G_NOARGS        8       /* Don't construct a @_ array. */
 654 #define G_KEEPERR      16       /* Append errors to $@, don't overwrite it */
 655 #define G_NODEBUG      32       /* Disable debugging at toplevel.  */
 656 #define G_METHOD       64       /* Calling method. */
 657 #define G_FAKINGEVAL  256       /* Faking en eval context for call_sv or
 658                                    fold_constants. */
 659
 660 /* flag bits for PL_in_eval */
 661 #define EVAL_NULL       0       /* not in an eval */
 662 #define EVAL_INEVAL     1       /* some enclosing scope is an eval */
 663 #define EVAL_WARNONLY   2       /* used by yywarn() when calling yyerror() */
 664 #define EVAL_KEEPERR    4       /* set by Perl_call_sv if G_KEEPERR */
 665 #define EVAL_INREQUIRE  8       /* The code is being required. */
 666
 667 /* Support for switching (stack and block) contexts.
 668  * This ensures magic doesn't invalidate local stack and cx pointers.
 669  */
 670
 671 #define PERLSI_UNKNOWN          -1
 672 #define PERLSI_UNDEF            0
 673 #define PERLSI_MAIN             1
 674 #define PERLSI_MAGIC            2
 675 #define PERLSI_SORT             3
 676 #define PERLSI_SIGNAL           4
 677 #define PERLSI_OVERLOAD         5
 678 #define PERLSI_DESTROY          6
 679 #define PERLSI_WARNHOOK         7
 680 #define PERLSI_DIEHOOK          8
 681 #define PERLSI_REQUIRE          9
 682
 683 struct stackinfo {
 684     AV *                si_stack;       /* stack for current runlevel */
 685     PERL_CONTEXT *      si_cxstack;     /* context stack for runlevel */
 686     I32                 si_cxix;        /* current context index */
 687     I32                 si_cxmax;       /* maximum allocated index */
 688     I32                 si_type;        /* type of runlevel */
 689     struct stackinfo *  si_prev;
 690     struct stackinfo *  si_next;
 691     I32                 si_markoff;     /* offset where markstack begins for us.
 692                                          * currently used only with DEBUGGING,
 693                                          * but not #ifdef-ed for bincompat */
 694 };
 695
 696 typedef struct stackinfo PERL_SI;
 697
 698 #define cxstack         (PL_curstackinfo->si_cxstack)
 699 #define cxstack_ix      (PL_curstackinfo->si_cxix)
 700 #define cxstack_max     (PL_curstackinfo->si_cxmax)
 701
 702 #ifdef DEBUGGING
 703 #  define       SET_MARK_OFFSET \
 704     PL_curstackinfo->si_markoff = PL_markstack_ptr - PL_markstack
 705 #else
 706 #  define       SET_MARK_OFFSET NOOP
 707 #endif
 708
 709 #define PUSHSTACKi(type) \
 710     STMT_START {                                                        \
 711         PERL_SI *next = PL_curstackinfo->si_next;                       \
 712         if (!next) {                                                    \
 713             next = new_stackinfo(32, 2048/sizeof(PERL_CONTEXT) - 1);    \
 714             next->si_prev = PL_curstackinfo;                            \
 715             PL_curstackinfo->si_next = next;                            \
 716         }                                                               \
 717         next->si_type = type;                                           \
 718         next->si_cxix = -1;                                             \
 719         AvFILLp(next->si_stack) = 0;                                    \
 720         SWITCHSTACK(PL_curstack,next->si_stack);                        \
 721         PL_curstackinfo = next;                                         \
 722         SET_MARK_OFFSET;                                                \
 723     } STMT_END
 724
 725 #define PUSHSTACK PUSHSTACKi(PERLSI_UNKNOWN)
 726
 727 /* POPSTACK works with PL_stack_sp, so it may need to be bracketed by
 728  * PUTBACK/SPAGAIN to flush/refresh any local SP that may be active */
 729 #define POPSTACK \
 730     STMT_START {                                                        \
 731         dSP;                                                            \
 732         PERL_SI * const prev = PL_curstackinfo->si_prev;                \
 733         if (!prev) {                                                    \
 734             PerlIO_printf(Perl_error_log, "panic: POPSTACK\n");         \
 735             my_exit(1);                                                 \
 736         }                                                               \
 737         SWITCHSTACK(PL_curstack,prev->si_stack);                        \
 738         /* don't free prev here, free them all at the END{} */          \
 739         PL_curstackinfo = prev;                                         \
 740     } STMT_END
 741
 742 #define POPSTACK_TO(s) \
 743     STMT_START {                                                        \
 744         while (PL_curstack != s) {                                      \
 745             dounwind(-1);                                               \
 746             POPSTACK;                                                   \
 747         }                                                               \
 748     } STMT_END
 749
 750 #define IN_PERL_COMPILETIME     (PL_curcop == &PL_compiling)
 751 #define IN_PERL_RUNTIME         (PL_curcop != &PL_compiling)
 752
 753 /*
 754 =head1 Multicall Functions
 755
 756 =for apidoc Ams||dMULTICALL
 757 Declare local variables for a multicall. See L<perlcall/Lightweight Callbacks>.
 758
 759 =for apidoc Ams||PUSH_MULTICALL
 760 Opening bracket for a lightweight callback.
 761 See L<perlcall/Lightweight Callbacks>.
 762
 763 =for apidoc Ams||MULTICALL
 764 Make a lightweight callback. See L<perlcall/Lightweight Callbacks>.
 765
 766 =for apidoc Ams||POP_MULTICALL
 767 Closing bracket for a lightweight callback.
 768 See L<perlcall/Lightweight Callbacks>.
 769
 770 =cut
 771 */
 772
 773 #define dMULTICALL \
 774     SV **newsp;                 /* set by POPBLOCK */                   \
 775     PERL_CONTEXT *cx;                                                   \
 776     CV *multicall_cv;                                                   \
 777     OP *multicall_cop;                                                  \
 778     bool multicall_oldcatch;                                            \
 779     U8 hasargs = 0              /* used by PUSHSUB */
 780
 781 #define PUSH_MULTICALL(the_cv) \
 782     STMT_START {                                                        \
 783         CV * const _nOnclAshIngNamE_ = the_cv;                          \
 784         CV * const cv = _nOnclAshIngNamE_;                              \
 785         AV * const padlist = CvPADLIST(cv);                             \
 786         ENTER;                                                          \
 787         multicall_oldcatch = CATCH_GET;                                 \
 788         SAVETMPS; SAVEVPTR(PL_op);                                      \
 789         CATCH_SET(TRUE);                                                \
 790         PUSHBLOCK(cx, CXt_SUB|CXp_MULTICALL, PL_stack_sp);              \
 791         PUSHSUB(cx);                                                    \
 792         if (++CvDEPTH(cv) >= 2) {                                       \
 793             PERL_STACK_OVERFLOW_CHECK();                                \
 794             Perl_pad_push(aTHX_ padlist, CvDEPTH(cv));                  \
 795         }                                                               \
 796         SAVECOMPPAD();                                                  \
 797         PAD_SET_CUR_NOSAVE(padlist, CvDEPTH(cv));                       \
 798         multicall_cv = cv;                                              \
 799         multicall_cop = CvSTART(cv);                                    \
 800     } STMT_END
 801
 802 #define MULTICALL \
 803     STMT_START {                                                        \
 804         PL_op = multicall_cop;                                          \
 805         CALLRUNOPS(aTHX);                                               \
 806     } STMT_END
 807
 808 #define POP_MULTICALL \
 809     STMT_START {                                                        \
 810         LEAVESUB(multicall_cv);                                         \
 811         CvDEPTH(multicall_cv)--;                                        \
 812         POPBLOCK(cx,PL_curpm);                                          \
 813         CATCH_SET(multicall_oldcatch);                                  \
 814         LEAVE;                                                          \
 815     } STMT_END
 816
 817 /*
 818  * Local variables:
 819  * c-indentation-style: bsd
 820  * c-basic-offset: 4
 821  * indent-tabs-mode: t
 822  * End:
 823  *
 824  * ex: set ts=8 sts=4 sw=4 noet:
 825  */