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_PLAIN(cx, 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_ITERDATA_SET(cx,NULL);
 510
 511 #define PUSHLOOP_FOR(cx, dat, s)                                        \
 512         cx->blk_loop.resetsp = s - PL_stack_base;                       \
 513         cx->blk_loop.my_op = cLOOP;                                     \
 514         PUSHLOOP_OP_NEXT;                                               \
 515         cx->blk_loop.iterlval = NULL;                                   \
 516         cx->blk_loop.iterary = NULL;                                    \
 517         cx->blk_loop.iterix = -1;                                       \
 518         CX_ITERDATA_SET(cx,dat);
 519
 520 #define POPLOOP(cx)                                                     \
 521         if (CxTYPE(cx) == CXt_LOOP_LAZYIV)                              \
 522             assert(!cx->blk_loop.iterlval);                             \
 523         SvREFCNT_dec(cx->blk_loop.iterlval);                            \
 524         if (CxITERVAR(cx)) {                                            \
 525             if (SvPADMY(cx->blk_loop.itersave)) {                       \
 526                 SV ** const s_v_p = CxITERVAR(cx);                      \
 527                 sv_2mortal(*s_v_p);                                     \
 528                 *s_v_p = cx->blk_loop.itersave;                         \
 529             }                                                           \
 530             else {                                                      \
 531                 SvREFCNT_dec(cx->blk_loop.itersave);                    \
 532             }                                                           \
 533         }                                                               \
 534         if ((CxTYPE(cx) != CXt_LOOP_STACK) && cx->blk_loop.iterary)     \
 535             SvREFCNT_dec(cx->blk_loop.iterary);
 536
 537 /* given/when context */
 538 struct block_givwhen {
 539         OP *leave_op;
 540 };
 541
 542 #define PUSHGIVEN(cx)                                                   \
 543         cx->blk_givwhen.leave_op = cLOGOP->op_other;
 544
 545 #define PUSHWHEN PUSHGIVEN
 546
 547 /* context common to subroutines, evals and loops */
 548 struct block {
 549     U8          blku_type;      /* what kind of context this is */
 550     U8          blku_gimme;     /* is this block running in list context? */
 551     U16         blku_u16;       /* used by block_sub and block_eval (so far) */
 552     I32         blku_oldsp;     /* stack pointer to copy stuff down to */
 553     COP *       blku_oldcop;    /* old curcop pointer */
 554     I32         blku_oldmarksp; /* mark stack index */
 555     I32         blku_oldscopesp;        /* scope stack index */
 556     PMOP *      blku_oldpm;     /* values of pattern match vars */
 557
 558     union {
 559         struct block_sub        blku_sub;
 560         struct block_format     blku_format;
 561         struct block_eval       blku_eval;
 562         struct block_loop       blku_loop;
 563         struct block_givwhen    blku_givwhen;
 564     } blk_u;
 565 };
 566 #define blk_oldsp       cx_u.cx_blk.blku_oldsp
 567 #define blk_oldcop      cx_u.cx_blk.blku_oldcop
 568 #define blk_oldmarksp   cx_u.cx_blk.blku_oldmarksp
 569 #define blk_oldscopesp  cx_u.cx_blk.blku_oldscopesp
 570 #define blk_oldpm       cx_u.cx_blk.blku_oldpm
 571 #define blk_gimme       cx_u.cx_blk.blku_gimme
 572 #define blk_u16         cx_u.cx_blk.blku_u16
 573 #define blk_sub         cx_u.cx_blk.blk_u.blku_sub
 574 #define blk_format      cx_u.cx_blk.blk_u.blku_format
 575 #define blk_eval        cx_u.cx_blk.blk_u.blku_eval
 576 #define blk_loop        cx_u.cx_blk.blk_u.blku_loop
 577 #define blk_givwhen     cx_u.cx_blk.blk_u.blku_givwhen
 578
 579 /* Enter a block. */
 580 #define PUSHBLOCK(cx,t,sp) CXINC, cx = &cxstack[cxstack_ix],            \
 581         cx->cx_type             = t,                                    \
 582         cx->blk_oldsp           = sp - PL_stack_base,                   \
 583         cx->blk_oldcop          = PL_curcop,                            \
 584         cx->blk_oldmarksp       = PL_markstack_ptr - PL_markstack,      \
 585         cx->blk_oldscopesp      = PL_scopestack_ix,                     \
 586         cx->blk_oldpm           = PL_curpm,                             \
 587         cx->blk_gimme           = (U8)gimme;                            \
 588         DEBUG_l( PerlIO_printf(Perl_debug_log, "Entering block %ld, type %s\n", \
 589                     (long)cxstack_ix, PL_block_type[CxTYPE(cx)]); )
 590
 591 /* Exit a block (RETURN and LAST). */
 592 #define POPBLOCK(cx,pm) cx = &cxstack[cxstack_ix--],                    \
 593         newsp            = PL_stack_base + cx->blk_oldsp,               \
 594         PL_curcop        = cx->blk_oldcop,                              \
 595         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
 596         PL_scopestack_ix = cx->blk_oldscopesp,                          \
 597         pm               = cx->blk_oldpm,                               \
 598         gimme            = cx->blk_gimme;                               \
 599         DEBUG_SCOPE("POPBLOCK");                                        \
 600         DEBUG_l( PerlIO_printf(Perl_debug_log, "Leaving block %ld, type %s\n",          \
 601                     (long)cxstack_ix+1,PL_block_type[CxTYPE(cx)]); )
 602
 603 /* Continue a block elsewhere (NEXT and REDO). */
 604 #define TOPBLOCK(cx) cx  = &cxstack[cxstack_ix],                        \
 605         PL_stack_sp      = PL_stack_base + cx->blk_oldsp,               \
 606         PL_markstack_ptr = PL_markstack + cx->blk_oldmarksp,            \
 607         PL_scopestack_ix = cx->blk_oldscopesp,                          \
 608         PL_curpm         = cx->blk_oldpm;                               \
 609         DEBUG_SCOPE("TOPBLOCK");
 610
 611 /* substitution context */
 612 struct subst {
 613     U8          sbu_type;       /* what kind of context this is */
 614     U8          sbu_rflags;
 615     U16         sbu_rxtainted;  /* matches struct block */
 616     I32         sbu_iters;
 617     I32         sbu_maxiters;
 618     I32         sbu_oldsave;
 619     char *      sbu_orig;
 620     SV *        sbu_dstr;
 621     SV *        sbu_targ;
 622     char *      sbu_s;
 623     char *      sbu_m;
 624     char *      sbu_strend;
 625     void *      sbu_rxres;
 626     REGEXP *    sbu_rx;
 627 };
 628 #define sb_iters        cx_u.cx_subst.sbu_iters
 629 #define sb_maxiters     cx_u.cx_subst.sbu_maxiters
 630 #define sb_rflags       cx_u.cx_subst.sbu_rflags
 631 #define sb_oldsave      cx_u.cx_subst.sbu_oldsave
 632 #define sb_once         cx_u.cx_subst.sbu_once
 633 #define sb_rxtainted    cx_u.cx_subst.sbu_rxtainted
 634 #define sb_orig         cx_u.cx_subst.sbu_orig
 635 #define sb_dstr         cx_u.cx_subst.sbu_dstr
 636 #define sb_targ         cx_u.cx_subst.sbu_targ
 637 #define sb_s            cx_u.cx_subst.sbu_s
 638 #define sb_m            cx_u.cx_subst.sbu_m
 639 #define sb_strend       cx_u.cx_subst.sbu_strend
 640 #define sb_rxres        cx_u.cx_subst.sbu_rxres
 641 #define sb_rx           cx_u.cx_subst.sbu_rx
 642
 643 #define PUSHSUBST(cx) CXINC, cx = &cxstack[cxstack_ix],                 \
 644         cx->sb_iters            = iters,                                \
 645         cx->sb_maxiters         = maxiters,                             \
 646         cx->sb_rflags           = r_flags,                              \
 647         cx->sb_oldsave          = oldsave,                              \
 648         cx->sb_rxtainted        = rxtainted,                            \
 649         cx->sb_orig             = orig,                                 \
 650         cx->sb_dstr             = dstr,                                 \
 651         cx->sb_targ             = targ,                                 \
 652         cx->sb_s                = s,                                    \
 653         cx->sb_m                = m,                                    \
 654         cx->sb_strend           = strend,                               \
 655         cx->sb_rxres            = NULL,                                 \
 656         cx->sb_rx               = rx,                                   \
 657         cx->cx_type             = CXt_SUBST | (once ? CXp_ONCE : 0);    \
 658         rxres_save(&cx->sb_rxres, rx);                                  \
 659         (void)ReREFCNT_inc(rx)
 660
 661 #define CxONCE(cx)              ((cx)->cx_type & CXp_ONCE)
 662
 663 #define POPSUBST(cx) cx = &cxstack[cxstack_ix--];                       \
 664         rxres_free(&cx->sb_rxres);                                      \
 665         ReREFCNT_dec(cx->sb_rx)
 666
 667 struct context {
 668     union {
 669         struct block    cx_blk;
 670         struct subst    cx_subst;
 671     } cx_u;
 672 };
 673 #define cx_type cx_u.cx_subst.sbu_type
 674
 675 #define CXTYPEMASK      0xf
 676 #define CXt_NULL        0
 677 #define CXt_SUB         1
 678 #define CXt_EVAL        2
 679 #define CXt_WHEN        3
 680 #define CXt_SUBST       4
 681 #define CXt_BLOCK       5
 682 #define CXt_FORMAT      6
 683 #define CXt_GIVEN       7
 684 /* This is first so that CXt_LOOP_FOR|CXt_LOOP_LAZYIV is CXt_LOOP_LAZYIV */
 685 #define CXt_LOOP_FOR    8
 686 #define CXt_LOOP_PLAIN  9
 687 /* Foreach on a temporary list on the stack */
 688 #define CXt_LOOP_STACK  10
 689 #define CXt_LOOP_LAZYIV 11
 690
 691 /* private flags for CXt_SUB and CXt_NULL
 692    However, this is checked in many places which do not check the type, so
 693    this bit needs to be kept clear for most everything else. For reasons I
 694    haven't investigated, it can coexist with CXp_FOR_DEF */
 695 #define CXp_MULTICALL   0x10    /* part of a multicall (so don't
 696                                    tear down context on exit). */
 697
 698 /* private flags for CXt_SUB and CXt_FORMAT */
 699 #define CXp_HASARGS     0x20
 700
 701 /* private flags for CXt_EVAL */
 702 #define CXp_REAL        0x20    /* truly eval'', not a lookalike */
 703 #define CXp_TRYBLOCK    0x40    /* eval{}, not eval'' or similar */
 704
 705 /* private flags for CXt_LOOP */
 706 #define CXp_FOR_DEF     0x10    /* foreach using $_ */
 707 #ifdef USE_ITHREADS
 708 #  define CXp_PADVAR    0x20    /* itervar lives on pad, iterdata has pad
 709                                    offset; if not set, iterdata holds GV* */
 710 #  define CxPADLOOP(c)  (CxTYPE_is_LOOP(c) && ((c)->cx_type & (CXp_PADVAR)))
 711 #endif
 712 /* private flags for CXt_SUBST */
 713 #define CXp_ONCE        0x10    /* What was sbu_once in struct subst */
 714
 715 #define CxTYPE(c)       ((c)->cx_type & CXTYPEMASK)
 716 #define CxTYPE_is_LOOP(c)       (((c)->cx_type & 0xC) == 0x8)
 717 #define CxMULTICALL(c)  (((c)->cx_type & CXp_MULTICALL)                 \
 718                          == CXp_MULTICALL)
 719 #define CxREALEVAL(c)   (((c)->cx_type & (CXTYPEMASK|CXp_REAL))         \
 720                          == (CXt_EVAL|CXp_REAL))
 721 #define CxTRYBLOCK(c)   (((c)->cx_type & (CXTYPEMASK|CXp_TRYBLOCK))     \
 722                          == (CXt_EVAL|CXp_TRYBLOCK))
 723 #define CxFOREACH(c)    (CxTYPE_is_LOOP(c) && CxTYPE(c) != CXt_LOOP_PLAIN)
 724 #define CxFOREACHDEF(c) ((CxTYPE_is_LOOP(c) && CxTYPE(c) != CXt_LOOP_PLAIN) \
 725                          && ((c)->cx_type & CXp_FOR_DEF))
 726
 727 #define CXINC (cxstack_ix < cxstack_max ? ++cxstack_ix : (cxstack_ix = cxinc()))
 728
 729 /*
 730 =head1 "Gimme" Values
 731 */
 732
 733 /*
 734 =for apidoc AmU||G_SCALAR
 735 Used to indicate scalar context.  See C<GIMME_V>, C<GIMME>, and
 736 L<perlcall>.
 737
 738 =for apidoc AmU||G_ARRAY
 739 Used to indicate list context.  See C<GIMME_V>, C<GIMME> and
 740 L<perlcall>.
 741
 742 =for apidoc AmU||G_VOID
 743 Used to indicate void context.  See C<GIMME_V> and L<perlcall>.
 744
 745 =for apidoc AmU||G_DISCARD
 746 Indicates that arguments returned from a callback should be discarded.  See
 747 L<perlcall>.
 748
 749 =for apidoc AmU||G_EVAL
 750
 751 Used to force a Perl C<eval> wrapper around a callback.  See
 752 L<perlcall>.
 753
 754 =for apidoc AmU||G_NOARGS
 755
 756 Indicates that no arguments are being sent to a callback.  See
 757 L<perlcall>.
 758
 759 =cut
 760 */
 761
 762 #define G_SCALAR        2
 763 #define G_ARRAY         3
 764 #define G_VOID          1
 765 #define G_WANT          3
 766
 767 /* extra flags for Perl_call_* routines */
 768 #define G_DISCARD       4       /* Call FREETMPS.
 769                                    Don't change this without consulting the
 770                                    hash actions codes defined in hv.h */
 771 #define G_EVAL          8       /* Assume eval {} around subroutine call. */
 772 #define G_NOARGS       16       /* Don't construct a @_ array. */
 773 #define G_KEEPERR      32       /* Append errors to $@, don't overwrite it */
 774 #define G_NODEBUG      64       /* Disable debugging at toplevel.  */
 775 #define G_METHOD      128       /* Calling method. */
 776 #define G_FAKINGEVAL  256       /* Faking an eval context for call_sv or
 777                                    fold_constants. */
 778
 779 /* flag bits for PL_in_eval */
 780 #define EVAL_NULL       0       /* not in an eval */
 781 #define EVAL_INEVAL     1       /* some enclosing scope is an eval */
 782 #define EVAL_WARNONLY   2       /* used by yywarn() when calling yyerror() */
 783 #define EVAL_KEEPERR    4       /* set by Perl_call_sv if G_KEEPERR */
 784 #define EVAL_INREQUIRE  8       /* The code is being required. */
 785
 786 /* Support for switching (stack and block) contexts.
 787  * This ensures magic doesn't invalidate local stack and cx pointers.
 788  */
 789
 790 #define PERLSI_UNKNOWN          -1
 791 #define PERLSI_UNDEF            0
 792 #define PERLSI_MAIN             1
 793 #define PERLSI_MAGIC            2
 794 #define PERLSI_SORT             3
 795 #define PERLSI_SIGNAL           4
 796 #define PERLSI_OVERLOAD         5
 797 #define PERLSI_DESTROY          6
 798 #define PERLSI_WARNHOOK         7
 799 #define PERLSI_DIEHOOK          8
 800 #define PERLSI_REQUIRE          9
 801
 802 struct stackinfo {
 803     AV *                si_stack;       /* stack for current runlevel */
 804     PERL_CONTEXT *      si_cxstack;     /* context stack for runlevel */
 805     struct stackinfo *  si_prev;
 806     struct stackinfo *  si_next;
 807     I32                 si_cxix;        /* current context index */
 808     I32                 si_cxmax;       /* maximum allocated index */
 809     I32                 si_type;        /* type of runlevel */
 810     I32                 si_markoff;     /* offset where markstack begins for us.
 811                                          * currently used only with DEBUGGING,
 812                                          * but not #ifdef-ed for bincompat */
 813 };
 814
 815 typedef struct stackinfo PERL_SI;
 816
 817 #define cxstack         (PL_curstackinfo->si_cxstack)
 818 #define cxstack_ix      (PL_curstackinfo->si_cxix)
 819 #define cxstack_max     (PL_curstackinfo->si_cxmax)
 820
 821 #ifdef DEBUGGING
 822 #  define       SET_MARK_OFFSET \
 823     PL_curstackinfo->si_markoff = PL_markstack_ptr - PL_markstack
 824 #else
 825 #  define       SET_MARK_OFFSET NOOP
 826 #endif
 827
 828 #define PUSHSTACKi(type) \
 829     STMT_START {                                                        \
 830         PERL_SI *next = PL_curstackinfo->si_next;                       \
 831         if (!next) {                                                    \
 832             next = new_stackinfo(32, 2048/sizeof(PERL_CONTEXT) - 1);    \
 833             next->si_prev = PL_curstackinfo;                            \
 834             PL_curstackinfo->si_next = next;                            \
 835         }                                                               \
 836         next->si_type = type;                                           \
 837         next->si_cxix = -1;                                             \
 838         AvFILLp(next->si_stack) = 0;                                    \
 839         SWITCHSTACK(PL_curstack,next->si_stack);                        \
 840         PL_curstackinfo = next;                                         \
 841         SET_MARK_OFFSET;                                                \
 842     } STMT_END
 843
 844 #define PUSHSTACK PUSHSTACKi(PERLSI_UNKNOWN)
 845
 846 /* POPSTACK works with PL_stack_sp, so it may need to be bracketed by
 847  * PUTBACK/SPAGAIN to flush/refresh any local SP that may be active */
 848 #define POPSTACK \
 849     STMT_START {                                                        \
 850         dSP;                                                            \
 851         PERL_SI * const prev = PL_curstackinfo->si_prev;                \
 852         if (!prev) {                                                    \
 853             PerlIO_printf(Perl_error_log, "panic: POPSTACK\n");         \
 854             my_exit(1);                                                 \
 855         }                                                               \
 856         SWITCHSTACK(PL_curstack,prev->si_stack);                        \
 857         /* don't free prev here, free them all at the END{} */          \
 858         PL_curstackinfo = prev;                                         \
 859     } STMT_END
 860
 861 #define POPSTACK_TO(s) \
 862     STMT_START {                                                        \
 863         while (PL_curstack != s) {                                      \
 864             dounwind(-1);                                               \
 865             POPSTACK;                                                   \
 866         }                                                               \
 867     } STMT_END
 868
 869 #define IN_PERL_COMPILETIME     (PL_curcop == &PL_compiling)
 870 #define IN_PERL_RUNTIME         (PL_curcop != &PL_compiling)
 871
 872 /*
 873 =head1 Multicall Functions
 874
 875 =for apidoc Ams||dMULTICALL
 876 Declare local variables for a multicall. See L<perlcall/Lightweight Callbacks>.
 877
 878 =for apidoc Ams||PUSH_MULTICALL
 879 Opening bracket for a lightweight callback.
 880 See L<perlcall/Lightweight Callbacks>.
 881
 882 =for apidoc Ams||MULTICALL
 883 Make a lightweight callback. See L<perlcall/Lightweight Callbacks>.
 884
 885 =for apidoc Ams||POP_MULTICALL
 886 Closing bracket for a lightweight callback.
 887 See L<perlcall/Lightweight Callbacks>.
 888
 889 =cut
 890 */
 891
 892 #define dMULTICALL \
 893     SV **newsp;                 /* set by POPBLOCK */                   \
 894     PERL_CONTEXT *cx;                                                   \
 895     CV *multicall_cv;                                                   \
 896     OP *multicall_cop;                                                  \
 897     bool multicall_oldcatch;                                            \
 898     U8 hasargs = 0              /* used by PUSHSUB */
 899
 900 #define PUSH_MULTICALL(the_cv) \
 901     STMT_START {                                                        \
 902         CV * const _nOnclAshIngNamE_ = the_cv;                          \
 903         CV * const cv = _nOnclAshIngNamE_;                              \
 904         AV * const padlist = CvPADLIST(cv);                             \
 905         ENTER;                                                          \
 906         multicall_oldcatch = CATCH_GET;                                 \
 907         SAVETMPS; SAVEVPTR(PL_op);                                      \
 908         CATCH_SET(TRUE);                                                \
 909         PUSHBLOCK(cx, CXt_SUB|CXp_MULTICALL, PL_stack_sp);              \
 910         PUSHSUB(cx);                                                    \
 911         if (++CvDEPTH(cv) >= 2) {                                       \
 912             PERL_STACK_OVERFLOW_CHECK();                                \
 913             Perl_pad_push(aTHX_ padlist, CvDEPTH(cv));                  \
 914         }                                                               \
 915         SAVECOMPPAD();                                                  \
 916         PAD_SET_CUR_NOSAVE(padlist, CvDEPTH(cv));                       \
 917         multicall_cv = cv;                                              \
 918         multicall_cop = CvSTART(cv);                                    \
 919     } STMT_END
 920
 921 #define MULTICALL \
 922     STMT_START {                                                        \
 923         PL_op = multicall_cop;                                          \
 924         CALLRUNOPS(aTHX);                                               \
 925     } STMT_END
 926
 927 #define POP_MULTICALL \
 928     STMT_START {                                                        \
 929         LEAVESUB(multicall_cv);                                         \
 930         CvDEPTH(multicall_cv)--;                                        \
 931         POPBLOCK(cx,PL_curpm);                                          \
 932         CATCH_SET(multicall_oldcatch);                                  \
 933         LEAVE;                                                          \
 934     } STMT_END
 935
 936 /*
 937  * Local variables:
 938  * c-indentation-style: bsd
 939  * c-basic-offset: 4
 940  * indent-tabs-mode: t
 941  * End:
 942  *
 943  * ex: set ts=8 sts=4 sw=4 noet:
 944  */