scope.h

   1 /*    scope.h
   2  *
   3  *    Copyright (c) 1997-2002, Larry Wall
   4  *
   5  *    You may distribute under the terms of either the GNU General Public
   6  *    License or the Artistic License, as specified in the README file.
   7  *
   8  */
   9
  10 #define SAVEt_ITEM              0
  11 #define SAVEt_SV                1
  12 #define SAVEt_AV                2
  13 #define SAVEt_HV                3
  14 #define SAVEt_INT               4
  15 #define SAVEt_LONG              5
  16 #define SAVEt_I32               6
  17 #define SAVEt_IV                7
  18 #define SAVEt_SPTR              8
  19 #define SAVEt_APTR              9
  20 #define SAVEt_HPTR              10
  21 #define SAVEt_PPTR              11
  22 #define SAVEt_NSTAB             12
  23 #define SAVEt_SVREF             13
  24 #define SAVEt_GP                14
  25 #define SAVEt_FREESV            15
  26 #define SAVEt_FREEOP            16
  27 #define SAVEt_FREEPV            17
  28 #define SAVEt_CLEARSV           18
  29 #define SAVEt_DELETE            19
  30 #define SAVEt_DESTRUCTOR        20
  31 #define SAVEt_REGCONTEXT        21
  32 #define SAVEt_STACK_POS         22
  33 #define SAVEt_I16               23
  34 #define SAVEt_AELEM             24
  35 #define SAVEt_HELEM             25
  36 #define SAVEt_OP                26
  37 #define SAVEt_HINTS             27
  38 #define SAVEt_ALLOC             28
  39 #define SAVEt_GENERIC_SVREF     29
  40 #define SAVEt_DESTRUCTOR_X      30
  41 #define SAVEt_VPTR              31
  42 #define SAVEt_I8                32
  43 #define SAVEt_COMPPAD           33
  44 #define SAVEt_GENERIC_PVREF     34
  45 #define SAVEt_PADSV             35
  46 #define SAVEt_MORTALIZESV       36
  47 #define SAVEt_SHARED_PVREF      37
  48
  49 #ifndef SCOPE_SAVES_SIGNAL_MASK
  50 #define SCOPE_SAVES_SIGNAL_MASK 0
  51 #endif
  52
  53 #define SSCHECK(need) if (PL_savestack_ix + need > PL_savestack_max) savestack_grow()
  54 #define SSPUSHINT(i) (PL_savestack[PL_savestack_ix++].any_i32 = (I32)(i))
  55 #define SSPUSHLONG(i) (PL_savestack[PL_savestack_ix++].any_long = (long)(i))
  56 #define SSPUSHIV(i) (PL_savestack[PL_savestack_ix++].any_iv = (IV)(i))
  57 #define SSPUSHPTR(p) (PL_savestack[PL_savestack_ix++].any_ptr = (void*)(p))
  58 #define SSPUSHDPTR(p) (PL_savestack[PL_savestack_ix++].any_dptr = (p))
  59 #define SSPUSHDXPTR(p) (PL_savestack[PL_savestack_ix++].any_dxptr = (p))
  60 #define SSPOPINT (PL_savestack[--PL_savestack_ix].any_i32)
  61 #define SSPOPLONG (PL_savestack[--PL_savestack_ix].any_long)
  62 #define SSPOPIV (PL_savestack[--PL_savestack_ix].any_iv)
  63 #define SSPOPPTR (PL_savestack[--PL_savestack_ix].any_ptr)
  64 #define SSPOPDPTR (PL_savestack[--PL_savestack_ix].any_dptr)
  65 #define SSPOPDXPTR (PL_savestack[--PL_savestack_ix].any_dxptr)
  66
  67 /*
  68 =head1 Callback Functions
  69
  70 =for apidoc Ams||SAVETMPS
  71 Opening bracket for temporaries on a callback.  See C<FREETMPS> and
  72 L<perlcall>.
  73
  74 =for apidoc Ams||FREETMPS
  75 Closing bracket for temporaries on a callback.  See C<SAVETMPS> and
  76 L<perlcall>.
  77
  78 =for apidoc Ams||ENTER
  79 Opening bracket on a callback.  See C<LEAVE> and L<perlcall>.
  80
  81 =for apidoc Ams||LEAVE
  82 Closing bracket on a callback.  See C<ENTER> and L<perlcall>.
  83
  84 =cut
  85 */
  86
  87 #define SAVETMPS save_int((int*)&PL_tmps_floor), PL_tmps_floor = PL_tmps_ix
  88 #define FREETMPS if (PL_tmps_ix > PL_tmps_floor) free_tmps()
  89
  90 #ifdef DEBUGGING
  91 #define ENTER                                                   \
  92     STMT_START {                                                \
  93         push_scope();                                           \
  94         DEBUG_l(WITH_THR(Perl_deb(aTHX_ "ENTER scope %ld at %s:%d\n",   \
  95                     PL_scopestack_ix, __FILE__, __LINE__)));    \
  96     } STMT_END
  97 #define LEAVE                                                   \
  98     STMT_START {                                                \
  99         DEBUG_l(WITH_THR(Perl_deb(aTHX_ "LEAVE scope %ld at %s:%d\n",   \
 100                     PL_scopestack_ix, __FILE__, __LINE__)));    \
 101         pop_scope();                                            \
 102     } STMT_END
 103 #else
 104 #define ENTER push_scope()
 105 #define LEAVE pop_scope()
 106 #endif
 107 #define LEAVE_SCOPE(old) if (PL_savestack_ix > old) leave_scope(old)
 108
 109 /*
 110  * Not using SOFT_CAST on SAVESPTR, SAVEGENERICSV and SAVEFREESV
 111  * because these are used for several kinds of pointer values
 112  */
 113 #define SAVEI8(i)       save_I8(SOFT_CAST(I8*)&(i))
 114 #define SAVEI16(i)      save_I16(SOFT_CAST(I16*)&(i))
 115 #define SAVEI32(i)      save_I32(SOFT_CAST(I32*)&(i))
 116 #define SAVEINT(i)      save_int(SOFT_CAST(int*)&(i))
 117 #define SAVEIV(i)       save_iv(SOFT_CAST(IV*)&(i))
 118 #define SAVELONG(l)     save_long(SOFT_CAST(long*)&(l))
 119 #define SAVESPTR(s)     save_sptr((SV**)&(s))
 120 #define SAVEPPTR(s)     save_pptr(SOFT_CAST(char**)&(s))
 121 #define SAVEVPTR(s)     save_vptr((void*)&(s))
 122 #define SAVEPADSV(s)    save_padsv(s)
 123 #define SAVEFREESV(s)   save_freesv((SV*)(s))
 124 #define SAVEMORTALIZESV(s)      save_mortalizesv((SV*)(s))
 125 #define SAVEFREEOP(o)   save_freeop(SOFT_CAST(OP*)(o))
 126 #define SAVEFREEPV(p)   save_freepv(SOFT_CAST(char*)(p))
 127 #define SAVECLEARSV(sv) save_clearsv(SOFT_CAST(SV**)&(sv))
 128 #define SAVEGENERICSV(s)        save_generic_svref((SV**)&(s))
 129 #define SAVEGENERICPV(s)        save_generic_pvref((char**)&(s))
 130 #define SAVESHAREDPV(s)         save_shared_pvref((char**)&(s))
 131 #define SAVEDELETE(h,k,l) \
 132           save_delete(SOFT_CAST(HV*)(h), SOFT_CAST(char*)(k), (I32)(l))
 133 #define SAVEDESTRUCTOR(f,p) \
 134           save_destructor((DESTRUCTORFUNC_NOCONTEXT_t)(f), SOFT_CAST(void*)(p))
 135
 136 #define SAVEDESTRUCTOR_X(f,p) \
 137           save_destructor_x((DESTRUCTORFUNC_t)(f), SOFT_CAST(void*)(p))
 138
 139 #define SAVESTACK_POS() \
 140     STMT_START {                                \
 141         SSCHECK(2);                             \
 142         SSPUSHINT(PL_stack_sp - PL_stack_base); \
 143         SSPUSHINT(SAVEt_STACK_POS);             \
 144     } STMT_END
 145
 146 #define SAVEOP()        save_op()
 147
 148 #define SAVEHINTS() \
 149     STMT_START {                                \
 150         if (PL_hints & HINT_LOCALIZE_HH)        \
 151             save_hints();                       \
 152         else {                                  \
 153             SSCHECK(2);                         \
 154             SSPUSHINT(PL_hints);                \
 155             SSPUSHINT(SAVEt_HINTS);             \
 156         }                                       \
 157     } STMT_END
 158
 159 #define SAVECOMPPAD() \
 160     STMT_START {                                                \
 161         if (PL_comppad && PL_curpad == AvARRAY(PL_comppad)) {   \
 162             SSCHECK(2);                                         \
 163             SSPUSHPTR((SV*)PL_comppad);                         \
 164             SSPUSHINT(SAVEt_COMPPAD);                           \
 165         }                                                       \
 166         else {                                                  \
 167             SAVEVPTR(PL_curpad);                                \
 168             SAVESPTR(PL_comppad);                               \
 169         }                                                       \
 170     } STMT_END
 171
 172 #ifdef USE_ITHREADS
 173 #  define SAVECOPSTASH(c)       SAVEPPTR(CopSTASHPV(c))
 174 #  define SAVECOPSTASH_FREE(c)  SAVESHAREDPV(CopSTASHPV(c))
 175 #  define SAVECOPFILE(c)        SAVEPPTR(CopFILE(c))
 176 #  define SAVECOPFILE_FREE(c)   SAVESHAREDPV(CopFILE(c))
 177 #else
 178 #  define SAVECOPSTASH(c)       SAVESPTR(CopSTASH(c))
 179 #  define SAVECOPSTASH_FREE(c)  SAVECOPSTASH(c) /* XXX not refcounted */
 180 #  define SAVECOPFILE(c)        SAVESPTR(CopFILEGV(c))
 181 #  define SAVECOPFILE_FREE(c)   SAVEGENERICSV(CopFILEGV(c))
 182 #endif
 183
 184 #define SAVECOPLINE(c)          SAVEI16(CopLINE(c))
 185
 186 /* SSNEW() temporarily allocates a specified number of bytes of data on the
 187  * savestack.  It returns an integer index into the savestack, because a
 188  * pointer would get broken if the savestack is moved on reallocation.
 189  * SSNEWa() works like SSNEW(), but also aligns the data to the specified
 190  * number of bytes.  MEM_ALIGNBYTES is perhaps the most useful.  The
 191  * alignment will be preserved therough savestack reallocation *only* if
 192  * realloc returns data aligned to a size divisible by `align'!
 193  *
 194  * SSPTR() converts the index returned by SSNEW/SSNEWa() into a pointer.
 195  */
 196
 197 #define SSNEW(size)             Perl_save_alloc(aTHX_ (size), 0)
 198 #define SSNEWt(n,t)             SSNEW((n)*sizeof(t))
 199 #define SSNEWa(size,align)      Perl_save_alloc(aTHX_ (size), \
 200     (align - ((int)((caddr_t)&PL_savestack[PL_savestack_ix]) % align)) % align)
 201 #define SSNEWat(n,t,align)      SSNEWa((n)*sizeof(t), align)
 202
 203 #define SSPTR(off,type)         ((type)  ((char*)PL_savestack + off))
 204 #define SSPTRt(off,type)        ((type*) ((char*)PL_savestack + off))
 205
 206 /* A jmpenv packages the state required to perform a proper non-local jump.
 207  * Note that there is a start_env initialized when perl starts, and top_env
 208  * points to this initially, so top_env should always be non-null.
 209  *
 210  * Existence of a non-null top_env->je_prev implies it is valid to call
 211  * longjmp() at that runlevel (we make sure start_env.je_prev is always
 212  * null to ensure this).
 213  *
 214  * je_mustcatch, when set at any runlevel to TRUE, means eval ops must
 215  * establish a local jmpenv to handle exception traps.  Care must be taken
 216  * to restore the previous value of je_mustcatch before exiting the
 217  * stack frame iff JMPENV_PUSH was not called in that stack frame.
 218  * GSAR 97-03-27
 219  */
 220
 221 struct jmpenv {
 222     struct jmpenv *     je_prev;
 223     Sigjmp_buf          je_buf;         /* only for use if !je_throw */
 224     int                 je_ret;         /* last exception thrown */
 225     bool                je_mustcatch;   /* need to call longjmp()? */
 226 #ifdef PERL_FLEXIBLE_EXCEPTIONS
 227     void                (*je_throw)(int v); /* last for bincompat */
 228     bool                je_noset;       /* no need for setjmp() */
 229 #endif
 230 };
 231
 232 typedef struct jmpenv JMPENV;
 233
 234 #ifdef OP_IN_REGISTER
 235 #define OP_REG_TO_MEM   PL_opsave = op
 236 #define OP_MEM_TO_REG   op = PL_opsave
 237 #else
 238 #define OP_REG_TO_MEM   NOOP
 239 #define OP_MEM_TO_REG   NOOP
 240 #endif
 241
 242 /*
 243  * How to build the first jmpenv.
 244  *
 245  * top_env needs to be non-zero. It points to an area
 246  * in which longjmp() stuff is stored, as C callstack
 247  * info there at least is thread specific this has to
 248  * be per-thread. Otherwise a 'die' in a thread gives
 249  * that thread the C stack of last thread to do an eval {}!
 250  */
 251
 252 #define JMPENV_BOOTSTRAP \
 253     STMT_START {                                \
 254         Zero(&PL_start_env, 1, JMPENV);         \
 255         PL_start_env.je_ret = -1;               \
 256         PL_start_env.je_mustcatch = TRUE;       \
 257         PL_top_env = &PL_start_env;             \
 258     } STMT_END
 259
 260 #ifdef PERL_FLEXIBLE_EXCEPTIONS
 261
 262 /*
 263  * These exception-handling macros are split up to
 264  * ease integration with C++ exceptions.
 265  *
 266  * To use C++ try+catch to catch Perl exceptions, an extension author
 267  * needs to first write an extern "C" function to throw an appropriate
 268  * exception object; typically it will be or contain an integer,
 269  * because Perl's internals use integers to track exception types:
 270  *    extern "C" { static void thrower(int i) { throw i; } }
 271  *
 272  * Then (as shown below) the author needs to use, not the simple
 273  * JMPENV_PUSH, but several of its constitutent macros, to arrange for
 274  * the Perl internals to call thrower() rather than longjmp() to
 275  * report exceptions:
 276  *
 277  *    dJMPENV;
 278  *    JMPENV_PUSH_INIT(thrower);
 279  *    try {
 280  *        ... stuff that may throw exceptions ...
 281  *    }
 282  *    catch (int why) {  // or whatever matches thrower()
 283  *        JMPENV_POST_CATCH;
 284  *        EXCEPT_SET(why);
 285  *        switch (why) {
 286  *          ... // handle various Perl exception codes
 287  *        }
 288  *    }
 289  *    JMPENV_POP;  // don't forget this!
 290  */
 291
 292 /*
 293  * Function that catches/throws, and its callback for the
 294  *  body of protected processing.
 295  */
 296 typedef void *(CPERLscope(*protect_body_t)) (pTHX_ va_list);
 297 typedef void *(CPERLscope(*protect_proc_t)) (pTHX_ volatile JMPENV *pcur_env,
 298                                              int *, protect_body_t, ...);
 299
 300 #define dJMPENV JMPENV cur_env; \
 301                 volatile JMPENV *pcur_env = ((cur_env.je_noset = 0),&cur_env)
 302
 303 #define JMPENV_PUSH_INIT_ENV(ce,THROWFUNC) \
 304     STMT_START {                                        \
 305         (ce).je_throw = (THROWFUNC);                    \
 306         (ce).je_ret = -1;                               \
 307         (ce).je_mustcatch = FALSE;                      \
 308         (ce).je_prev = PL_top_env;                      \
 309         PL_top_env = &(ce);                             \
 310         OP_REG_TO_MEM;                                  \
 311     } STMT_END
 312
 313 #define JMPENV_PUSH_INIT(THROWFUNC) JMPENV_PUSH_INIT_ENV(*(JMPENV*)pcur_env,THROWFUNC)
 314
 315 #define JMPENV_POST_CATCH_ENV(ce) \
 316     STMT_START {                                        \
 317         OP_MEM_TO_REG;                                  \
 318         PL_top_env = &(ce);                             \
 319     } STMT_END
 320
 321 #define JMPENV_POST_CATCH JMPENV_POST_CATCH_ENV(*(JMPENV*)pcur_env)
 322
 323 #define JMPENV_PUSH_ENV(ce,v) \
 324     STMT_START {                                                \
 325         if (!(ce).je_noset) {                                   \
 326             DEBUG_l(Perl_deb(aTHX_ "Setting up jumplevel %p, was %p\n", \
 327                              ce, PL_top_env));                  \
 328             JMPENV_PUSH_INIT_ENV(ce,NULL);                      \
 329             EXCEPT_SET_ENV(ce,PerlProc_setjmp((ce).je_buf, SCOPE_SAVES_SIGNAL_MASK));\
 330             (ce).je_noset = 1;                                  \
 331         }                                                       \
 332         else                                                    \
 333             EXCEPT_SET_ENV(ce,0);                               \
 334         JMPENV_POST_CATCH_ENV(ce);                              \
 335         (v) = EXCEPT_GET_ENV(ce);                               \
 336     } STMT_END
 337
 338 #define JMPENV_PUSH(v) JMPENV_PUSH_ENV(*(JMPENV*)pcur_env,v)
 339
 340 #define JMPENV_POP_ENV(ce) \
 341     STMT_START {                                                \
 342         if (PL_top_env == &(ce))                                \
 343             PL_top_env = (ce).je_prev;                          \
 344     } STMT_END
 345
 346 #define JMPENV_POP  JMPENV_POP_ENV(*(JMPENV*)pcur_env)
 347
 348 #define JMPENV_JUMP(v) \
 349     STMT_START {                                                \
 350         OP_REG_TO_MEM;                                          \
 351         if (PL_top_env->je_prev) {                              \
 352             if (PL_top_env->je_throw)                           \
 353                 PL_top_env->je_throw(v);                        \
 354             else                                                \
 355                 PerlProc_longjmp(PL_top_env->je_buf, (v));      \
 356         }                                                       \
 357         if ((v) == 2)                                           \
 358             PerlProc_exit(STATUS_NATIVE_EXPORT);                \
 359         PerlIO_printf(Perl_error_log, "panic: top_env\n");      \
 360         PerlProc_exit(1);                                       \
 361     } STMT_END
 362
 363 #define EXCEPT_GET_ENV(ce)      ((ce).je_ret)
 364 #define EXCEPT_GET              EXCEPT_GET_ENV(*(JMPENV*)pcur_env)
 365 #define EXCEPT_SET_ENV(ce,v)    ((ce).je_ret = (v))
 366 #define EXCEPT_SET(v)           EXCEPT_SET_ENV(*(JMPENV*)pcur_env,v)
 367
 368 #else /* !PERL_FLEXIBLE_EXCEPTIONS */
 369
 370 #define dJMPENV         JMPENV cur_env
 371
 372 #define JMPENV_PUSH(v) \
 373     STMT_START {                                                        \
 374         DEBUG_l(Perl_deb(aTHX_ "Setting up jumplevel %p, was %p\n",     \
 375                          &cur_env, PL_top_env));                        \
 376         cur_env.je_prev = PL_top_env;                                   \
 377         OP_REG_TO_MEM;                                                  \
 378         cur_env.je_ret = PerlProc_setjmp(cur_env.je_buf, SCOPE_SAVES_SIGNAL_MASK);              \
 379         OP_MEM_TO_REG;                                                  \
 380         PL_top_env = &cur_env;                                          \
 381         cur_env.je_mustcatch = FALSE;                                   \
 382         (v) = cur_env.je_ret;                                           \
 383     } STMT_END
 384
 385 #define JMPENV_POP \
 386     STMT_START { PL_top_env = cur_env.je_prev; } STMT_END
 387
 388 #define JMPENV_JUMP(v) \
 389     STMT_START {                                                \
 390         OP_REG_TO_MEM;                                          \
 391         if (PL_top_env->je_prev)                                \
 392             PerlProc_longjmp(PL_top_env->je_buf, (v));          \
 393         if ((v) == 2)                                           \
 394             PerlProc_exit(STATUS_NATIVE_EXPORT);                \
 395         PerlIO_printf(PerlIO_stderr(), "panic: top_env\n");     \
 396         PerlProc_exit(1);                                       \
 397     } STMT_END
 398
 399 #endif /* PERL_FLEXIBLE_EXCEPTIONS */
 400
 401 #define CATCH_GET               (PL_top_env->je_mustcatch)
 402 #define CATCH_SET(v)            (PL_top_env->je_mustcatch = (v))