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, 2007, 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                          (void*)&cur_env, (void*)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                          (void*)PL_top_env, (void*)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 #include "mydtrace.h"
 136
 137 struct cop {
 138     BASEOP
 139     /* On LP64 putting this here takes advantage of the fact that BASEOP isn't
 140        an exact multiple of 8 bytes to save structure padding.  */
 141     line_t      cop_line;       /* line # of this command */
 142     char *      cop_label;      /* label for this construct */
 143 #ifdef USE_ITHREADS
 144     char *      cop_stashpv;    /* package line was compiled in */
 145     char *      cop_file;       /* file name the following line # is from */
 146 #else
 147     HV *        cop_stash;      /* package line was compiled in */
 148     GV *        cop_filegv;     /* file the following line # is from */
 149 #endif
 150     U32         cop_hints;      /* hints bits from pragmata */
 151     U32         cop_seq;        /* parse sequence number */
 152     /* Beware. mg.c and warnings.pl assume the type of this is STRLEN *:  */
 153     STRLEN *    cop_warnings;   /* lexical warnings bitmask */
 154     /* compile time state of %^H.  See the comment in op.c for how this is
 155        used to recreate a hash to return from caller.  */
 156     struct refcounted_he * cop_hints_hash;
 157 };
 158
 159 #ifdef USE_ITHREADS
 160 #  define CopFILE(c)            ((c)->cop_file)
 161 #  define CopFILEGV(c)          (CopFILE(c) \
 162                                  ? gv_fetchfile(CopFILE(c)) : NULL)
 163
 164 #  ifdef NETWARE
 165 #    define CopFILE_set(c,pv)   ((c)->cop_file = savepv(pv))
 166 #    define CopFILE_setn(c,pv,l)  ((c)->cop_file = savepv((pv),(l)))
 167 #  else
 168 #    define CopFILE_set(c,pv)   ((c)->cop_file = savesharedpv(pv))
 169 #    define CopFILE_setn(c,pv,l)  ((c)->cop_file = savesharedpvn((pv),(l)))
 170 #  endif
 171
 172 #  define CopFILESV(c)          (CopFILE(c) \
 173                                  ? GvSV(gv_fetchfile(CopFILE(c))) : NULL)
 174 #  define CopFILEAV(c)          (CopFILE(c) \
 175                                  ? GvAV(gv_fetchfile(CopFILE(c))) : NULL)
 176 #  ifdef DEBUGGING
 177 #    define CopFILEAVx(c)       (assert(CopFILE(c)), \
 178                                    GvAV(gv_fetchfile(CopFILE(c))))
 179 #  else
 180 #    define CopFILEAVx(c)       (GvAV(gv_fetchfile(CopFILE(c))))
 181 #  endif
 182 #  define CopSTASHPV(c)         ((c)->cop_stashpv)
 183
 184 #  ifdef NETWARE
 185 #    define CopSTASHPV_set(c,pv)        ((c)->cop_stashpv = ((pv) ? savepv(pv) : NULL))
 186 #  else
 187 #    define CopSTASHPV_set(c,pv)        ((c)->cop_stashpv = savesharedpv(pv))
 188 #  endif
 189
 190 #  define CopSTASH(c)           (CopSTASHPV(c) \
 191                                  ? gv_stashpv(CopSTASHPV(c),GV_ADD) : NULL)
 192 #  define CopSTASH_set(c,hv)    CopSTASHPV_set(c, (hv) ? HvNAME_get(hv) : NULL)
 193 #  define CopSTASH_eq(c,hv)     ((hv) && stashpv_hvname_match(c,hv))
 194 #  define CopLABEL(c)           ((c)->cop_label)
 195 #  define CopLABEL_set(c,pv)    (CopLABEL(c) = (pv))
 196 #  ifdef NETWARE
 197 #    define CopSTASH_free(c) SAVECOPSTASH_FREE(c)
 198 #    define CopFILE_free(c) SAVECOPFILE_FREE(c)
 199 #    define CopLABEL_free(c) SAVECOPLABEL_FREE(c)
 200 #    define CopLABEL_alloc(pv)  ((pv)?savepv(pv):NULL)
 201 #  else
 202 #    define CopSTASH_free(c)    PerlMemShared_free(CopSTASHPV(c))
 203 #    define CopFILE_free(c)     (PerlMemShared_free(CopFILE(c)),(CopFILE(c) = NULL))
 204 #    define CopLABEL_free(c)    (PerlMemShared_free(CopLABEL(c)),(CopLABEL(c) = NULL))
 205 #    define CopLABEL_alloc(pv)  ((pv)?savesharedpv(pv):NULL)
 206 #  endif
 207 #else
 208 #  define CopFILEGV(c)          ((c)->cop_filegv)
 209 #  define CopFILEGV_set(c,gv)   ((c)->cop_filegv = (GV*)SvREFCNT_inc(gv))
 210 #  define CopFILE_set(c,pv)     CopFILEGV_set((c), gv_fetchfile(pv))
 211 #  define CopFILE_setn(c,pv,l)  CopFILEGV_set((c), gv_fetchfile_flags((pv),(l),0))
 212 #  define CopFILESV(c)          (CopFILEGV(c) ? GvSV(CopFILEGV(c)) : NULL)
 213 #  define CopFILEAV(c)          (CopFILEGV(c) ? GvAV(CopFILEGV(c)) : NULL)
 214 #  ifdef DEBUGGING
 215 #    define CopFILEAVx(c)       (assert(CopFILEGV(c)), GvAV(CopFILEGV(c)))
 216 #  else
 217 #    define CopFILEAVx(c)       (GvAV(CopFILEGV(c)))
 218 # endif
 219 #  define CopFILE(c)            (CopFILEGV(c) && GvSV(CopFILEGV(c)) \
 220                                     ? SvPVX(GvSV(CopFILEGV(c))) : NULL)
 221 #  define CopSTASH(c)           ((c)->cop_stash)
 222 #  define CopLABEL(c)           ((c)->cop_label)
 223 #  define CopSTASH_set(c,hv)    ((c)->cop_stash = (hv))
 224 #  define CopSTASHPV(c)         (CopSTASH(c) ? HvNAME_get(CopSTASH(c)) : NULL)
 225    /* cop_stash is not refcounted */
 226 #  define CopSTASHPV_set(c,pv)  CopSTASH_set((c), gv_stashpv(pv,GV_ADD))
 227 #  define CopSTASH_eq(c,hv)     (CopSTASH(c) == (hv))
 228 #  define CopLABEL_alloc(pv)    ((pv)?savepv(pv):NULL)
 229 #  define CopLABEL_set(c,pv)    (CopLABEL(c) = (pv))
 230 #  define CopSTASH_free(c)
 231 #  define CopFILE_free(c)       (SvREFCNT_dec(CopFILEGV(c)),(CopFILEGV(c) = NULL))
 232 #  define CopLABEL_free(c)      (Safefree(CopLABEL(c)),(CopLABEL(c) = NULL))
 233
 234 #endif /* USE_ITHREADS */
 235
 236 #define CopSTASH_ne(c,hv)       (!CopSTASH_eq(c,hv))
 237 #define CopLINE(c)              ((c)->cop_line)
 238 #define CopLINE_inc(c)          (++CopLINE(c))
 239 #define CopLINE_dec(c)          (--CopLINE(c))
 240 #define CopLINE_set(c,l)        (CopLINE(c) = (l))
 241
 242 /* OutCopFILE() is CopFILE for output (caller, die, warn, etc.) */
 243 #ifdef MACOS_TRADITIONAL
 244 #  define OutCopFILE(c) MacPerl_MPWFileName(CopFILE(c))
 245 #else
 246 #  define OutCopFILE(c) CopFILE(c)
 247 #endif
 248
 249 /* If $[ is non-zero, it's stored in cop_hints under the key "$[", and
 250    HINT_ARYBASE is set to indicate this.
 251    Setting it is ineficient due to the need to create 2 mortal SVs, but as
 252    using $[ is highly discouraged, no sane Perl code will be using it.  */
 253 #define CopARYBASE_get(c)       \
 254         ((CopHINTS_get(c) & HINT_ARYBASE)                               \
 255          ? SvIV(Perl_refcounted_he_fetch(aTHX_ (c)->cop_hints_hash, 0,  \
 256                                          "$[", 2, 0, 0))                \
 257          : 0)
 258 #define CopARYBASE_set(c, b) STMT_START { \
 259         if (b || ((c)->cop_hints & HINT_ARYBASE)) {                     \
 260             (c)->cop_hints |= HINT_ARYBASE;                             \
 261             if ((c) == &PL_compiling)                                   \
 262                 PL_hints |= HINT_LOCALIZE_HH | HINT_ARYBASE;            \
 263             (c)->cop_hints_hash                                         \
 264                = Perl_refcounted_he_new(aTHX_ (c)->cop_hints_hash,      \
 265                                         newSVpvs_flags("$[", SVs_TEMP), \
 266                                         sv_2mortal(newSViv(b)));        \
 267         }                                                               \
 268     } STMT_END
 269
 270 /* FIXME NATIVE_HINTS if this is changed from op_private (see perl.h)  */
 271 #define CopHINTS_get(c)         ((c)->cop_hints + 0)
 272 #define CopHINTS_set(c, h)      STMT_START {                            \
 273                                     (c)->cop_hints = (h);               \
 274                                 } STMT_END
 275
 276 /*
 277  * Here we have some enormously heavy (or at least ponderous) wizardry.
 278  */
 279
 280 /* subroutine context */
 281 struct block_sub {
 282     OP *        retop;  /* op to execute on exit from sub */
 283     /* Above here is the same for sub, format and eval.  */
 284     CV *        cv;
 285     /* Above here is the same for sub and format.  */
 286     AV *        savearray;
 287     AV *        argarray;
 288     I32         olddepth;
 289     PAD         *oldcomppad;
 290 };
 291
 292
 293 /* format context */
 294 struct block_format {
 295     OP *        retop;  /* op to execute on exit from sub */
 296     /* Above here is the same for sub, format and eval.  */
 297     CV *        cv;
 298     /* Above here is the same for sub and format.  */
 299     GV *        gv;
 300     GV *        dfoutgv;
 301 };
 302
 303 /* base for the next two macros. Don't use directly.
 304  * Note that the refcnt of the cv is incremented twice;  The CX one is
 305  * decremented by LEAVESUB, the other by LEAVE. */
 306
 307 #define PUSHSUB_BASE(cx)                                                \
 308         ENTRY_PROBE(GvENAME(CvGV(cv)),                                  \
 309                 CopFILE((COP*)CvSTART(cv)),                             \
 310                 CopLINE((COP*)CvSTART(cv)));                            \
 311                                                                         \
 312         cx->blk_sub.cv = cv;                                            \
 313         cx->blk_sub.olddepth = CvDEPTH(cv);                             \
 314         cx->cx_type |= (hasargs) ? CXp_HASARGS : 0;                     \
 315         cx->blk_sub.retop = NULL;                                       \
 316         if (!CvDEPTH(cv)) {                                             \
 317             SvREFCNT_inc_simple_void_NN(cv);                            \
 318             SvREFCNT_inc_simple_void_NN(cv);                            \
 319             SAVEFREESV(cv);                                             \
 320         }
 321
 322
 323 #define PUSHSUB(cx)                                                     \
 324         PUSHSUB_BASE(cx)                                                \
 325         cx->blk_u16 = PL_op->op_private &                               \
 326                               (OPpLVAL_INTRO|OPpENTERSUB_INARGS);
 327
 328 /* variant for use by OP_DBSTATE, where op_private holds hint bits */
 329 #define PUSHSUB_DB(cx)                                                  \
 330         PUSHSUB_BASE(cx)                                                \
 331         cx->blk_u16 = 0;
 332
 333
 334 #define PUSHFORMAT(cx, retop)                                           \
 335         cx->blk_format.cv = cv;                                         \
 336         cx->blk_format.gv = gv;                                         \
 337         cx->blk_format.retop = (retop);                                 \
 338         cx->blk_format.dfoutgv = PL_defoutgv;                           \
 339         SvREFCNT_inc_void(cx->blk_format.dfoutgv)
 340
 341 #define POP_SAVEARRAY()                                         \
 342     STMT_START {                                                        \
 343         SvREFCNT_dec(GvAV(PL_defgv));                                   \
 344         GvAV(PL_defgv) = cx->blk_sub.savearray;                         \
 345     } STMT_END
 346
 347 /* junk in @_ spells trouble when cloning CVs and in pp_caller(), so don't
 348  * leave any (a fast av_clear(ary), basically) */
 349 #define CLEAR_ARGARRAY(ary) \
 350     STMT_START {                                                        \
 351         AvMAX(ary) += AvARRAY(ary) - AvALLOC(ary);                      \
 352         AvARRAY(ary) = AvALLOC(ary);                                    \
 353         AvFILLp(ary) = -1;                                              \
 354     } STMT_END
 355
 356 #define POPSUB(cx,sv)                                                   \
 357     STMT_START {                                                        \
 358         RETURN_PROBE(GvENAME(CvGV((CV*)cx->blk_sub.cv)),                \
 359                 CopFILE((COP*)CvSTART((CV*)cx->blk_sub.cv)),            \
 360                 CopLINE((COP*)CvSTART((CV*)cx->blk_sub.cv)));           \
 361                                                                         \
 362         if (CxHASARGS(cx)) {                                            \
 363             POP_SAVEARRAY();                                            \
 364             /* abandon @_ if it got reified */                          \
 365             if (AvREAL(cx->blk_sub.argarray)) {                         \
 366                 const SSize_t fill = AvFILLp(cx->blk_sub.argarray);     \
 367                 SvREFCNT_dec(cx->blk_sub.argarray);                     \
 368                 cx->blk_sub.argarray = newAV();                         \
 369                 av_extend(cx->blk_sub.argarray, fill);                  \
 370                 AvREIFY_only(cx->blk_sub.argarray);                     \
 371                 CX_CURPAD_SV(cx->blk_sub, 0) = (SV*)cx->blk_sub.argarray;       \
 372             }                                                           \
 373             else {                                                      \
 374                 CLEAR_ARGARRAY(cx->blk_sub.argarray);                   \
 375             }                                                           \
 376         }                                                               \
 377         sv = (SV*)cx->blk_sub.cv;                                       \
 378         if (sv && (CvDEPTH((CV*)sv) = cx->blk_sub.olddepth))            \
 379             sv = NULL;                                          \
 380     } STMT_END
 381
 382 #define LEAVESUB(sv)                                                    \
 383     STMT_START {                                                        \
 384         if (sv)                                                         \
 385             SvREFCNT_dec(sv);                                           \
 386     } STMT_END
 387
 388 #define POPFORMAT(cx)                                                   \
 389         setdefout(cx->blk_format.dfoutgv);                              \
 390         SvREFCNT_dec(cx->blk_format.dfoutgv);
 391
 392 /* eval context */
 393 struct block_eval {
 394     OP *        retop;  /* op to execute on exit from eval */
 395     /* Above here is the same for sub, format and eval.  */
 396     SV *        old_namesv;
 397     OP *        old_eval_root;
 398     SV *        cur_text;
 399     CV *        cv;
 400     JMPENV *    cur_top_env; /* value of PL_top_env when eval CX created */
 401 };
 402
 403 /* If we ever need more than 512 op types, change the shift from 7.
 404    blku_gimme is actually also only 2 bits, so could be merged with something.
 405 */
 406
 407 #define CxOLD_IN_EVAL(cx)       (((cx)->blk_u16) & 0x7F)
 408 #define CxOLD_OP_TYPE(cx)       (((cx)->blk_u16) >> 7)
 409
 410 #define PUSHEVAL(cx,n,fgv)                                              \
 411     STMT_START {                                                        \
 412         assert(!(PL_in_eval & ~0x7F));                                  \
 413         assert(!(PL_op->op_type & ~0x1FF));                             \
 414         cx->blk_u16 = (PL_in_eval & 0x7F) | ((U16)PL_op->op_type << 7); \
 415         cx->blk_eval.old_namesv = (n ? newSVpv(n,0) : NULL);            \
 416         cx->blk_eval.old_eval_root = PL_eval_root;                      \
 417         cx->blk_eval.cur_text = PL_parser ? PL_parser->linestr : NULL;  \
 418         cx->blk_eval.cv = NULL; /* set by doeval(), as applicable */    \
 419         cx->blk_eval.retop = NULL;                                      \
 420         cx->blk_eval.cur_top_env = PL_top_env;                          \
 421     } STMT_END
 422
 423 #define POPEVAL(cx)                                                     \
 424     STMT_START {                                                        \
 425         PL_in_eval = CxOLD_IN_EVAL(cx);                                 \
 426         optype = CxOLD_OP_TYPE(cx);                                     \
 427         PL_eval_root = cx->blk_eval.old_eval_root;                      \
 428         if (cx->blk_eval.old_namesv)                                    \
 429             sv_2mortal(cx->blk_eval.old_namesv);                        \
 430     } STMT_END
 431
 432 /* loop context */
 433 struct block_loop {
 434     I32         resetsp;
 435     LOOP *      my_op;  /* My op, that contains redo, next and last ops.  */
 436     /* (except for non_ithreads we need to modify next_op in pp_ctl.c, hence
 437         why next_op is conditionally defined below.)  */
 438 #ifdef USE_ITHREADS
 439     void *      iterdata;
 440     PAD         *oldcomppad;
 441 #else
 442     OP *        next_op;
 443     SV **       itervar;
 444 #endif
 445     SV *        itersave;
 446     /* (from inspection of source code) for a .. range of strings this is the
 447        current string.  */
 448     SV *        iterlval;
 449     /* (from inspection of source code) for a foreach loop this is the array
 450        being iterated over. For a .. range of numbers it's the current value.
 451        A check is often made on the SvTYPE of iterary to determine whether
 452        we are iterating over an array or a range. (numbers or strings)  */
 453     AV *        iterary;
 454     IV          iterix;
 455     /* (from inspection of source code) for a .. range of numbers this is the
 456        maximum value.  */
 457     IV          itermax;
 458 };
 459 /* It might be possible to squeeze this structure further. As best I can tell
 460    itermax and iterlval are never used at the same time, so it might be possible
 461    to make them into a union. However, I'm not confident that there are enough
 462    flag bits/NULLable pointers in this structure alone to encode which is
 463    active. There is, however, U8 of space free in struct block, which could be
 464    used. Right now it may not be worth squeezing this structure further, as it's
 465    the largest part of struct block, and currently struct block is 64 bytes on
 466    an ILP32 system, which will give good cache alignment.
 467 */
 468
 469 #ifdef USE_ITHREADS
 470 #  define CxITERVAR(c)                                                  \
 471         ((c)->blk_loop.iterdata                                         \
 472          ? (CxPADLOOP(cx)                                               \
 473             ? &CX_CURPAD_SV( (c)->blk_loop,                             \
 474                     INT2PTR(PADOFFSET, (c)->blk_loop.iterdata))         \
 475             : &GvSV((GV*)(c)->blk_loop.iterdata))                       \
 476          : (SV**)NULL)
 477 #  define CX_ITERDATA_SET(cx,idata)                                     \
 478         CX_CURPAD_SAVE(cx->blk_loop);                                   \
 479         if ((cx->blk_loop.iterdata = (idata)))                          \
 480             cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));       \
 481         else                                                            \
 482             cx->blk_loop.itersave = NULL;
 483 #else
 484 #  define CxITERVAR(c)          ((c)->blk_loop.itervar)
 485 #  define CX_ITERDATA_SET(cx,ivar)                                      \
 486         if ((cx->blk_loop.itervar = (SV**)(ivar)))                      \
 487             cx->blk_loop.itersave = SvREFCNT_inc(*CxITERVAR(cx));       \
 488         else                                                            \
 489             cx->blk_loop.itersave = NULL;
 490 #endif
 491 #define CxLABEL(c)      (0 + (c)->blk_oldcop->cop_label)
 492 #define CxHASARGS(c)    (((c)->cx_type & CXp_HASARGS) == CXp_HASARGS)
 493 #define CxLVAL(c)       (0 + (c)->blk_u16)
 494
 495 #ifdef USE_ITHREADS
 496 #  define PUSHLOOP_OP_NEXT              /* No need to do anything.  */
 497 #  define CX_LOOP_NEXTOP_GET(cx)        ((cx)->blk_loop.my_op->op_nextop + 0)
 498 #else
 499 #  define PUSHLOOP_OP_NEXT              cx->blk_loop.next_op = cLOOP->op_nextop
 500 #  define CX_LOOP_NEXTOP_GET(cx)        ((cx)->blk_loop.next_op + 0)
 501 #endif
 502
 503 #define PUSHLOOP(cx, dat, s)                                            \
 504         cx->blk_loop.resetsp = s - PL_stack_base;                       \
 505         cx->blk_loop.my_op = cLOOP;                                     \
 506         PUSHLOOP_OP_NEXT;                                               \
 507         cx->blk_loop.iterlval = NULL;                                   \
 508         cx->blk_loop.iterary = NULL;                                    \
 509         cx->blk_loop.iterix = -1;                                       \
 510         CX_ITERDATA_SET(cx,dat);
 511
 512 #define POPLOOP(cx)                                                     \
 513         SvREFCNT_dec(cx->blk_loop.iterlval);                            \
 514         if (CxITERVAR(cx)) {                                            \
 515             if (SvPADMY(cx->blk_loop.itersave)) {                       \
 516                 SV ** const s_v_p = CxITERVAR(cx);                      \
 517                 sv_2mortal(*s_v_p);                                     \
 518                 *s_v_p = cx->blk_loop.itersave;                         \
 519             }                                                           \
 520             else {                                                      \
 521                 SvREFCNT_dec(cx->blk_loop.itersave);                    \
 522             }                                                           \
 523         }                                                               \
 524         if (cx->blk_loop.iterary && cx->blk_loop.iterary != PL_curstack)\
 525             SvREFCNT_dec(cx->blk_loop.iterary);
 526
 527 /* given/when context */
 528 struct block_givwhen {
 529         OP *leave_op;
 530 };
 531
 532 #define PUSHGIVEN(cx)                                                   \
 533         cx->blk_givwhen.leave_op = cLOGOP->op_other;
 534
 535 #define PUSHWHEN PUSHGIVEN
 536
 537 /* context common to subroutines, evals and loops */
 538 struct block {
 539     U8          blku_type;      /* what kind of context this is */
 540     U8          blku_gimme;     /* is this block running in list context? */
 541     U16         blku_u16;       /* used by block_sub and block_eval (so far) */
 542     I32         blku_oldsp;     /* stack pointer to copy stuff down to */
 543     COP *       blku_oldcop;    /* old curcop pointer */
 544     I32         blku_oldmarksp; /* mark stack index */
 545     I32         blku_oldscopesp;        /* scope stack index */
 546     PMOP *      blku_oldpm;     /* values of pattern match vars */
 547
 548     union {
 549         struct block_sub        blku_sub;
 550         struct block_format     blku_format;
 551         struct block_eval       blku_eval;
 552         struct block_loop       blku_loop;
 553         struct block_givwhen    blku_givwhen;
 554     } blk_u;
 555 };
 556 #define blk_oldsp       cx_u.cx_blk.blku_oldsp
 557 #define blk_oldcop      cx_u.cx_blk.blku_oldcop
 558 #define blk_oldmarksp   cx_u.cx_blk.blku_oldmarksp
 559 #define blk_oldscopesp  cx_u.cx_blk.blku_oldscopesp
 560 #define blk_oldpm       cx_u.cx_blk.blku_oldpm
 561 #define blk_gimme       cx_u.cx_blk.blku_gimme
 562 #define blk_u16         cx_u.cx_blk.blku_u16
 563 #define blk_sub         cx_u.cx_blk.blk_u.blku_sub
 564 #define blk_format      cx_u.cx_blk.blk_u.blku_format
 565 #define blk_eval        cx_u.cx_blk.blk_u.blku_eval
 566 #define blk_loop        cx_u.cx_blk.blk_u.blku_loop
 567 #define blk_givwhen     cx_u.cx_blk.blk_u.blku_givwhen
 568
 569 /* Enter a block. */
 570 #define PUSHBLOCK(cx,t,sp) CXINC, cx = &cxstack[cxstack_ix],            \
 571         cx->cx_type             = t,                                    \
 572         cx->blk_oldsp           = sp - PL_stack_base,                   \
 573         cx->blk_oldcop          = PL_curcop,                            \
 574         cx->blk_oldmarksp       = PL_markstack_ptr - PL_markstack,      \
 575         cx->blk_oldscopesp      = PL_scopestack_ix,                     \
 576         cx->blk_oldpm           = PL_curpm,                             \
 577         cx->blk_gimme           = (U8)gimme;                            \
 578         DEBUG_l( PerlIO_printf(Perl_debug_log, "Entering block %ld, type %s\n", \
 579                     (long)cxstack_ix, PL_block_type[CxTYPE(cx)]); )
 580
 581 /* Exit a block (RETURN and LAST). */
 582 #define POPBLOCK(cx,pm) cx = &cxstack[cxstack_ix--],                    \
 583         newsp            = PL_stack_base + cx->blk_oldsp,               \
 584         PL_curcop        = cx->blk_oldcop,                              \
 585         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
 586         PL_scopestack_ix = cx->blk_oldscopesp,                          \
 587         pm               = cx->blk_oldpm,                               \
 588         gimme            = cx->blk_gimme;                               \
 589         DEBUG_SCOPE("POPBLOCK");                                        \
 590         DEBUG_l( PerlIO_printf(Perl_debug_log, "Leaving block %ld, type %s\n",          \
 591                     (long)cxstack_ix+1,PL_block_type[CxTYPE(cx)]); )
 592
 593 /* Continue a block elsewhere (NEXT and REDO). */
 594 #define TOPBLOCK(cx) cx  = &cxstack[cxstack_ix],                        \
 595         PL_stack_sp      = PL_stack_base + cx->blk_oldsp,               \
 596         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
 597         PL_scopestack_ix = cx->blk_oldscopesp,                          \
 598         PL_curpm         = cx->blk_oldpm;                               \
 599         DEBUG_SCOPE("TOPBLOCK");
 600
 601 /* substitution context */
 602 struct subst {
 603     U8          sbu_type;       /* what kind of context this is */
 604     U8          sbu_rflags;
 605     U16         sbu_rxtainted;  /* matches struct block */
 606     I32         sbu_iters;
 607     I32         sbu_maxiters;
 608     I32         sbu_oldsave;
 609     char *      sbu_orig;
 610     SV *        sbu_dstr;
 611     SV *        sbu_targ;
 612     char *      sbu_s;
 613     char *      sbu_m;
 614     char *      sbu_strend;
 615     void *      sbu_rxres;
 616     REGEXP *    sbu_rx;
 617 };
 618 #define sb_iters        cx_u.cx_subst.sbu_iters
 619 #define sb_maxiters     cx_u.cx_subst.sbu_maxiters
 620 #define sb_rflags       cx_u.cx_subst.sbu_rflags
 621 #define sb_oldsave      cx_u.cx_subst.sbu_oldsave
 622 #define sb_once         cx_u.cx_subst.sbu_once
 623 #define sb_rxtainted    cx_u.cx_subst.sbu_rxtainted
 624 #define sb_orig         cx_u.cx_subst.sbu_orig
 625 #define sb_dstr         cx_u.cx_subst.sbu_dstr
 626 #define sb_targ         cx_u.cx_subst.sbu_targ
 627 #define sb_s            cx_u.cx_subst.sbu_s
 628 #define sb_m            cx_u.cx_subst.sbu_m
 629 #define sb_strend       cx_u.cx_subst.sbu_strend
 630 #define sb_rxres        cx_u.cx_subst.sbu_rxres
 631 #define sb_rx           cx_u.cx_subst.sbu_rx
 632
 633 #define PUSHSUBST(cx) CXINC, cx = &cxstack[cxstack_ix],                 \
 634         cx->sb_iters            = iters,                                \
 635         cx->sb_maxiters         = maxiters,                             \
 636         cx->sb_rflags           = r_flags,                              \
 637         cx->sb_oldsave          = oldsave,                              \
 638         cx->sb_rxtainted        = rxtainted,                            \
 639         cx->sb_orig             = orig,                                 \
 640         cx->sb_dstr             = dstr,                                 \
 641         cx->sb_targ             = targ,                                 \
 642         cx->sb_s                = s,                                    \
 643         cx->sb_m                = m,                                    \
 644         cx->sb_strend           = strend,                               \
 645         cx->sb_rxres            = NULL,                                 \
 646         cx->sb_rx               = rx,                                   \
 647         cx->cx_type             = CXt_SUBST | (once ? CXp_ONCE : 0);    \
 648         rxres_save(&cx->sb_rxres, rx);                                  \
 649         (void)ReREFCNT_inc(rx)
 650
 651 #define CxONCE(cx)              ((cx)->cx_type & CXp_ONCE)
 652
 653 #define POPSUBST(cx) cx = &cxstack[cxstack_ix--];                       \
 654         rxres_free(&cx->sb_rxres);                                      \
 655         ReREFCNT_dec(cx->sb_rx)
 656
 657 struct context {
 658     union {
 659         struct block    cx_blk;
 660         struct subst    cx_subst;
 661     } cx_u;
 662 };
 663 #define cx_type cx_u.cx_subst.sbu_type
 664
 665 #define CXTYPEMASK      0xf
 666 #define CXt_NULL        0
 667 #define CXt_SUB         1
 668 #define CXt_EVAL        2
 669 #define CXt_LOOP        3
 670 #define CXt_SUBST       4
 671 #define CXt_BLOCK       5
 672 #define CXt_FORMAT      6
 673 #define CXt_GIVEN       7
 674 #define CXt_WHEN        8
 675
 676 /* private flags for CXt_SUB and CXt_NULL
 677    However, this is checked in many places which do not check the type, so
 678    this bit needs to be kept clear for most everything else. For reasons I
 679    haven't investigated, it can coexist with CXp_FOR_DEF */
 680 #define CXp_MULTICALL   0x10    /* part of a multicall (so don't
 681                                    tear down context on exit). */
 682
 683 /* private flags for CXt_SUB and CXt_FORMAT */
 684 #define CXp_HASARGS     0x20
 685
 686 /* private flags for CXt_EVAL */
 687 #define CXp_REAL        0x20    /* truly eval'', not a lookalike */
 688 #define CXp_TRYBLOCK    0x40    /* eval{}, not eval'' or similar */
 689
 690 /* private flags for CXt_LOOP */
 691 #define CXp_FOR_DEF     0x10    /* foreach using $_ */
 692 #define CXp_FOREACH     0x20    /* a foreach loop */
 693 #ifdef USE_ITHREADS
 694 #  define CXp_PADVAR    0x40    /* itervar lives on pad, iterdata has pad
 695                                    offset; if not set, iterdata holds GV* */
 696 #  define CxPADLOOP(c)  (((c)->cx_type & (CXt_LOOP|CXp_PADVAR))         \
 697                          == (CXt_LOOP|CXp_PADVAR))
 698 #endif
 699 /* private flags for CXt_SUBST */
 700 #define CXp_ONCE        0x10    /* What was sbu_once in struct subst */
 701
 702 #define CxTYPE(c)       ((c)->cx_type & CXTYPEMASK)
 703 #define CxMULTICALL(c)  (((c)->cx_type & CXp_MULTICALL)                 \
 704                          == CXp_MULTICALL)
 705 #define CxREALEVAL(c)   (((c)->cx_type & (CXTYPEMASK|CXp_REAL))         \
 706                          == (CXt_EVAL|CXp_REAL))
 707 #define CxTRYBLOCK(c)   (((c)->cx_type & (CXTYPEMASK|CXp_TRYBLOCK))     \
 708                          == (CXt_EVAL|CXp_TRYBLOCK))
 709 #define CxFOREACH(c)    (((c)->cx_type & (CXTYPEMASK|CXp_FOREACH))      \
 710                          == (CXt_LOOP|CXp_FOREACH))
 711 #define CxFOREACHDEF(c) (((c)->cx_type & (CXTYPEMASK|CXp_FOREACH|CXp_FOR_DEF))\
 712                          == (CXt_LOOP|CXp_FOREACH|CXp_FOR_DEF))
 713
 714 #define CXINC (cxstack_ix < cxstack_max ? ++cxstack_ix : (cxstack_ix = cxinc()))
 715
 716 /*
 717 =head1 "Gimme" Values
 718 */
 719
 720 /*
 721 =for apidoc AmU||G_SCALAR
 722 Used to indicate scalar context.  See C<GIMME_V>, C<GIMME>, and
 723 L<perlcall>.
 724
 725 =for apidoc AmU||G_ARRAY
 726 Used to indicate list context.  See C<GIMME_V>, C<GIMME> and
 727 L<perlcall>.
 728
 729 =for apidoc AmU||G_VOID
 730 Used to indicate void context.  See C<GIMME_V> and L<perlcall>.
 731
 732 =for apidoc AmU||G_DISCARD
 733 Indicates that arguments returned from a callback should be discarded.  See
 734 L<perlcall>.
 735
 736 =for apidoc AmU||G_EVAL
 737
 738 Used to force a Perl C<eval> wrapper around a callback.  See
 739 L<perlcall>.
 740
 741 =for apidoc AmU||G_NOARGS
 742
 743 Indicates that no arguments are being sent to a callback.  See
 744 L<perlcall>.
 745
 746 =cut
 747 */
 748
 749 #define G_SCALAR        2
 750 #define G_ARRAY         3
 751 #define G_VOID          1
 752 #define G_WANT          3
 753
 754 /* extra flags for Perl_call_* routines */
 755 #define G_DISCARD       4       /* Call FREETMPS.
 756                                    Don't change this without consulting the
 757                                    hash actions codes defined in hv.h */
 758 #define G_EVAL          8       /* Assume eval {} around subroutine call. */
 759 #define G_NOARGS       16       /* Don't construct a @_ array. */
 760 #define G_KEEPERR      32       /* Append errors to $@, don't overwrite it */
 761 #define G_NODEBUG      64       /* Disable debugging at toplevel.  */
 762 #define G_METHOD      128       /* Calling method. */
 763 #define G_FAKINGEVAL  256       /* Faking an eval context for call_sv or
 764                                    fold_constants. */
 765
 766 /* flag bits for PL_in_eval */
 767 #define EVAL_NULL       0       /* not in an eval */
 768 #define EVAL_INEVAL     1       /* some enclosing scope is an eval */
 769 #define EVAL_WARNONLY   2       /* used by yywarn() when calling yyerror() */
 770 #define EVAL_KEEPERR    4       /* set by Perl_call_sv if G_KEEPERR */
 771 #define EVAL_INREQUIRE  8       /* The code is being required. */
 772
 773 /* Support for switching (stack and block) contexts.
 774  * This ensures magic doesn't invalidate local stack and cx pointers.
 775  */
 776
 777 #define PERLSI_UNKNOWN          -1
 778 #define PERLSI_UNDEF            0
 779 #define PERLSI_MAIN             1
 780 #define PERLSI_MAGIC            2
 781 #define PERLSI_SORT             3
 782 #define PERLSI_SIGNAL           4
 783 #define PERLSI_OVERLOAD         5
 784 #define PERLSI_DESTROY          6
 785 #define PERLSI_WARNHOOK         7
 786 #define PERLSI_DIEHOOK          8
 787 #define PERLSI_REQUIRE          9
 788
 789 struct stackinfo {
 790     AV *                si_stack;       /* stack for current runlevel */
 791     PERL_CONTEXT *      si_cxstack;     /* context stack for runlevel */
 792     struct stackinfo *  si_prev;
 793     struct stackinfo *  si_next;
 794     I32                 si_cxix;        /* current context index */
 795     I32                 si_cxmax;       /* maximum allocated index */
 796     I32                 si_type;        /* type of runlevel */
 797     I32                 si_markoff;     /* offset where markstack begins for us.
 798                                          * currently used only with DEBUGGING,
 799                                          * but not #ifdef-ed for bincompat */
 800 };
 801
 802 typedef struct stackinfo PERL_SI;
 803
 804 #define cxstack         (PL_curstackinfo->si_cxstack)
 805 #define cxstack_ix      (PL_curstackinfo->si_cxix)
 806 #define cxstack_max     (PL_curstackinfo->si_cxmax)
 807
 808 #ifdef DEBUGGING
 809 #  define       SET_MARK_OFFSET \
 810     PL_curstackinfo->si_markoff = PL_markstack_ptr - PL_markstack
 811 #else
 812 #  define       SET_MARK_OFFSET NOOP
 813 #endif
 814
 815 #define PUSHSTACKi(type) \
 816     STMT_START {                                                        \
 817         PERL_SI *next = PL_curstackinfo->si_next;                       \
 818         if (!next) {                                                    \
 819             next = new_stackinfo(32, 2048/sizeof(PERL_CONTEXT) - 1);    \
 820             next->si_prev = PL_curstackinfo;                            \
 821             PL_curstackinfo->si_next = next;                            \
 822         }                                                               \
 823         next->si_type = type;                                           \
 824         next->si_cxix = -1;                                             \
 825         AvFILLp(next->si_stack) = 0;                                    \
 826         SWITCHSTACK(PL_curstack,next->si_stack);                        \
 827         PL_curstackinfo = next;                                         \
 828         SET_MARK_OFFSET;                                                \
 829     } STMT_END
 830
 831 #define PUSHSTACK PUSHSTACKi(PERLSI_UNKNOWN)
 832
 833 /* POPSTACK works with PL_stack_sp, so it may need to be bracketed by
 834  * PUTBACK/SPAGAIN to flush/refresh any local SP that may be active */
 835 #define POPSTACK \
 836     STMT_START {                                                        \
 837         dSP;                                                            \
 838         PERL_SI * const prev = PL_curstackinfo->si_prev;                \
 839         if (!prev) {                                                    \
 840             PerlIO_printf(Perl_error_log, "panic: POPSTACK\n");         \
 841             my_exit(1);                                                 \
 842         }                                                               \
 843         SWITCHSTACK(PL_curstack,prev->si_stack);                        \
 844         /* don't free prev here, free them all at the END{} */          \
 845         PL_curstackinfo = prev;                                         \
 846     } STMT_END
 847
 848 #define POPSTACK_TO(s) \
 849     STMT_START {                                                        \
 850         while (PL_curstack != s) {                                      \
 851             dounwind(-1);                                               \
 852             POPSTACK;                                                   \
 853         }                                                               \
 854     } STMT_END
 855
 856 #define IN_PERL_COMPILETIME     (PL_curcop == &PL_compiling)
 857 #define IN_PERL_RUNTIME         (PL_curcop != &PL_compiling)
 858
 859 /*
 860 =head1 Multicall Functions
 861
 862 =for apidoc Ams||dMULTICALL
 863 Declare local variables for a multicall. See L<perlcall/Lightweight Callbacks>.
 864
 865 =for apidoc Ams||PUSH_MULTICALL
 866 Opening bracket for a lightweight callback.
 867 See L<perlcall/Lightweight Callbacks>.
 868
 869 =for apidoc Ams||MULTICALL
 870 Make a lightweight callback. See L<perlcall/Lightweight Callbacks>.
 871
 872 =for apidoc Ams||POP_MULTICALL
 873 Closing bracket for a lightweight callback.
 874 See L<perlcall/Lightweight Callbacks>.
 875
 876 =cut
 877 */
 878
 879 #define dMULTICALL \
 880     SV **newsp;                 /* set by POPBLOCK */                   \
 881     PERL_CONTEXT *cx;                                                   \
 882     CV *multicall_cv;                                                   \
 883     OP *multicall_cop;                                                  \
 884     bool multicall_oldcatch;                                            \
 885     U8 hasargs = 0              /* used by PUSHSUB */
 886
 887 #define PUSH_MULTICALL(the_cv) \
 888     STMT_START {                                                        \
 889         CV * const _nOnclAshIngNamE_ = the_cv;                          \
 890         CV * const cv = _nOnclAshIngNamE_;                              \
 891         AV * const padlist = CvPADLIST(cv);                             \
 892         ENTER;                                                          \
 893         multicall_oldcatch = CATCH_GET;                                 \
 894         SAVETMPS; SAVEVPTR(PL_op);                                      \
 895         CATCH_SET(TRUE);                                                \
 896         PUSHBLOCK(cx, CXt_SUB|CXp_MULTICALL, PL_stack_sp);              \
 897         PUSHSUB(cx);                                                    \
 898         if (++CvDEPTH(cv) >= 2) {                                       \
 899             PERL_STACK_OVERFLOW_CHECK();                                \
 900             Perl_pad_push(aTHX_ padlist, CvDEPTH(cv));                  \
 901         }                                                               \
 902         SAVECOMPPAD();                                                  \
 903         PAD_SET_CUR_NOSAVE(padlist, CvDEPTH(cv));                       \
 904         multicall_cv = cv;                                              \
 905         multicall_cop = CvSTART(cv);                                    \
 906     } STMT_END
 907
 908 #define MULTICALL \
 909     STMT_START {                                                        \
 910         PL_op = multicall_cop;                                          \
 911         CALLRUNOPS(aTHX);                                               \
 912     } STMT_END
 913
 914 #define POP_MULTICALL \
 915     STMT_START {                                                        \
 916         LEAVESUB(multicall_cv);                                         \
 917         CvDEPTH(multicall_cv)--;                                        \
 918         POPBLOCK(cx,PL_curpm);                                          \
 919         CATCH_SET(multicall_oldcatch);                                  \
 920         LEAVE;                                                          \
 921     } STMT_END
 922
 923 /*
 924  * Local variables:
 925  * c-indentation-style: bsd
 926  * c-basic-offset: 4
 927  * indent-tabs-mode: t
 928  * End:
 929  *
 930  * ex: set ts=8 sts=4 sw=4 noet:
 931  */