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