scope.h

   1 /*    scope.h
   2  *
   3  *    Copyright (C) 1993, 1994, 1996, 1997, 1998, 1999,
   4  *    2000, 2001, 2002, 2004, 2005 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  */
  10
  11 #define SAVEt_ITEM              0
  12 #define SAVEt_SV                1
  13 #define SAVEt_AV                2
  14 #define SAVEt_HV                3
  15 #define SAVEt_INT               4
  16 #define SAVEt_LONG              5
  17 #define SAVEt_I32               6
  18 #define SAVEt_IV                7
  19 #define SAVEt_SPTR              8
  20 #define SAVEt_APTR              9
  21 #define SAVEt_HPTR              10
  22 #define SAVEt_PPTR              11
  23 #define SAVEt_NSTAB             12
  24 #define SAVEt_SVREF             13
  25 #define SAVEt_GP                14
  26 #define SAVEt_FREESV            15
  27 #define SAVEt_FREEOP            16
  28 #define SAVEt_FREEPV            17
  29 #define SAVEt_CLEARSV           18
  30 #define SAVEt_DELETE            19
  31 #define SAVEt_DESTRUCTOR        20
  32 #define SAVEt_REGCONTEXT        21
  33 #define SAVEt_STACK_POS         22
  34 #define SAVEt_I16               23
  35 #define SAVEt_AELEM             24
  36 #define SAVEt_HELEM             25
  37 #define SAVEt_OP                26
  38 #define SAVEt_HINTS             27
  39 #define SAVEt_ALLOC             28
  40 #define SAVEt_GENERIC_SVREF     29
  41 #define SAVEt_DESTRUCTOR_X      30
  42 #define SAVEt_VPTR              31
  43 #define SAVEt_I8                32
  44 #define SAVEt_COMPPAD           33
  45 #define SAVEt_GENERIC_PVREF     34
  46 #define SAVEt_PADSV             35
  47 #define SAVEt_MORTALIZESV       36
  48 #define SAVEt_SHARED_PVREF      37
  49 #define SAVEt_BOOL              38
  50 #define SAVEt_SET_SVFLAGS       39
  51 #define SAVEt_SAVESWITCHSTACK   40
  52
  53 #ifndef SCOPE_SAVES_SIGNAL_MASK
  54 #define SCOPE_SAVES_SIGNAL_MASK 0
  55 #endif
  56
  57 #define SSCHECK(need) if (PL_savestack_ix + (need) > PL_savestack_max) savestack_grow()
  58 #define SSGROW(need) if (PL_savestack_ix + (need) > PL_savestack_max) savestack_grow_cnt(need)
  59 #define SSPUSHINT(i) (PL_savestack[PL_savestack_ix++].any_i32 = (I32)(i))
  60 #define SSPUSHLONG(i) (PL_savestack[PL_savestack_ix++].any_long = (long)(i))
  61 #define SSPUSHBOOL(p) (PL_savestack[PL_savestack_ix++].any_bool = (p))
  62 #define SSPUSHIV(i) (PL_savestack[PL_savestack_ix++].any_iv = (IV)(i))
  63 #define SSPUSHPTR(p) (PL_savestack[PL_savestack_ix++].any_ptr = (void*)(p))
  64 #define SSPUSHDPTR(p) (PL_savestack[PL_savestack_ix++].any_dptr = (p))
  65 #define SSPUSHDXPTR(p) (PL_savestack[PL_savestack_ix++].any_dxptr = (p))
  66 #define SSPOPINT (PL_savestack[--PL_savestack_ix].any_i32)
  67 #define SSPOPLONG (PL_savestack[--PL_savestack_ix].any_long)
  68 #define SSPOPBOOL (PL_savestack[--PL_savestack_ix].any_bool)
  69 #define SSPOPIV (PL_savestack[--PL_savestack_ix].any_iv)
  70 #define SSPOPPTR (PL_savestack[--PL_savestack_ix].any_ptr)
  71 #define SSPOPDPTR (PL_savestack[--PL_savestack_ix].any_dptr)
  72 #define SSPOPDXPTR (PL_savestack[--PL_savestack_ix].any_dxptr)
  73
  74 /*
  75 =head1 Callback Functions
  76
  77 =for apidoc Ams||SAVETMPS
  78 Opening bracket for temporaries on a callback.  See C<FREETMPS> and
  79 L<perlcall>.
  80
  81 =for apidoc Ams||FREETMPS
  82 Closing bracket for temporaries on a callback.  See C<SAVETMPS> and
  83 L<perlcall>.
  84
  85 =for apidoc Ams||ENTER
  86 Opening bracket on a callback.  See C<LEAVE> and L<perlcall>.
  87
  88 =for apidoc Ams||LEAVE
  89 Closing bracket on a callback.  See C<ENTER> and L<perlcall>.
  90
  91 =cut
  92 */
  93
  94 #define SAVETMPS save_int((int*)&PL_tmps_floor), PL_tmps_floor = PL_tmps_ix
  95 #define FREETMPS if (PL_tmps_ix > PL_tmps_floor) free_tmps()
  96
  97 #ifdef DEBUGGING
  98 #define ENTER                                                   \
  99     STMT_START {                                                \
 100         push_scope();                                           \
 101         DEBUG_SCOPE("ENTER")                                    \
 102     } STMT_END
 103 #define LEAVE                                                   \
 104     STMT_START {                                                \
 105         DEBUG_SCOPE("LEAVE")                                    \
 106         pop_scope();                                            \
 107     } STMT_END
 108 #else
 109 #define ENTER push_scope()
 110 #define LEAVE pop_scope()
 111 #endif
 112 #define LEAVE_SCOPE(old) if (PL_savestack_ix > old) leave_scope(old)
 113
 114 /*
 115  * Not using SOFT_CAST on SAVESPTR, SAVEGENERICSV and SAVEFREESV
 116  * because these are used for several kinds of pointer values
 117  */
 118 #define SAVEI8(i)       save_I8(SOFT_CAST(I8*)&(i))
 119 #define SAVEI16(i)      save_I16(SOFT_CAST(I16*)&(i))
 120 #define SAVEI32(i)      save_I32(SOFT_CAST(I32*)&(i))
 121 #define SAVEINT(i)      save_int(SOFT_CAST(int*)&(i))
 122 #define SAVEIV(i)       save_iv(SOFT_CAST(IV*)&(i))
 123 #define SAVELONG(l)     save_long(SOFT_CAST(long*)&(l))
 124 #define SAVEBOOL(b)     save_bool(SOFT_CAST(bool*)&(b))
 125 #define SAVESPTR(s)     save_sptr((SV**)&(s))
 126 #define SAVEPPTR(s)     save_pptr(SOFT_CAST(char**)&(s))
 127 #define SAVEVPTR(s)     save_vptr((void*)&(s))
 128 #define SAVEPADSV(s)    save_padsv(s)
 129 #define SAVEFREESV(s)   save_freesv((SV*)(s))
 130 #define SAVEMORTALIZESV(s)      save_mortalizesv((SV*)(s))
 131 #define SAVEFREEOP(o)   save_freeop(SOFT_CAST(OP*)(o))
 132 #define SAVEFREEPV(p)   save_freepv(SOFT_CAST(char*)(p))
 133 #define SAVECLEARSV(sv) save_clearsv(SOFT_CAST(SV**)&(sv))
 134 #define SAVEGENERICSV(s)        save_generic_svref((SV**)&(s))
 135 #define SAVEGENERICPV(s)        save_generic_pvref((char**)&(s))
 136 #define SAVESHAREDPV(s)         save_shared_pvref((char**)&(s))
 137 #define SAVESETSVFLAGS(sv,mask,val)     save_set_svflags(sv,mask,val)
 138 #define SAVEDELETE(h,k,l) \
 139           save_delete(SOFT_CAST(HV*)(h), SOFT_CAST(char*)(k), (I32)(l))
 140 #define SAVEDESTRUCTOR(f,p) \
 141           save_destructor((DESTRUCTORFUNC_NOCONTEXT_t)(f), SOFT_CAST(void*)(p))
 142
 143 #define SAVEDESTRUCTOR_X(f,p) \
 144           save_destructor_x((DESTRUCTORFUNC_t)(f), SOFT_CAST(void*)(p))
 145
 146 #define SAVESTACK_POS() \
 147     STMT_START {                                \
 148         SSCHECK(2);                             \
 149         SSPUSHINT(PL_stack_sp - PL_stack_base); \
 150         SSPUSHINT(SAVEt_STACK_POS);             \
 151     } STMT_END
 152
 153 #define SAVEOP()        save_op()
 154
 155 #define SAVEHINTS() \
 156     STMT_START {                                        \
 157         SSCHECK(3);                                     \
 158         if (PL_hints & HINT_LOCALIZE_HH) {              \
 159             SSPUSHPTR(GvHV(PL_hintgv));                 \
 160             GvHV(PL_hintgv) = newHVhv(GvHV(PL_hintgv)); \
 161         }                                               \
 162         SSPUSHINT(PL_hints);                            \
 163         SSPUSHINT(SAVEt_HINTS);                         \
 164     } STMT_END
 165
 166 #define SAVECOMPPAD() \
 167     STMT_START {                                                \
 168         SSCHECK(2);                                             \
 169         SSPUSHPTR((SV*)PL_comppad);                             \
 170         SSPUSHINT(SAVEt_COMPPAD);                               \
 171     } STMT_END
 172
 173 #define SAVESWITCHSTACK(f,t) \
 174     STMT_START {                                        \
 175         SSCHECK(3);                                     \
 176         SSPUSHPTR((SV*)(f));                            \
 177         SSPUSHPTR((SV*)(t));                            \
 178         SSPUSHINT(SAVEt_SAVESWITCHSTACK);               \
 179         SWITCHSTACK((f),(t));                           \
 180         PL_curstackinfo->si_stack = (t);                \
 181     } STMT_END
 182
 183 #ifdef USE_ITHREADS
 184 #  define SAVECOPSTASH(c)       SAVEPPTR(CopSTASHPV(c))
 185 #  define SAVECOPSTASH_FREE(c)  SAVESHAREDPV(CopSTASHPV(c))
 186 #  define SAVECOPFILE(c)        SAVEPPTR(CopFILE(c))
 187 #  define SAVECOPFILE_FREE(c)   SAVESHAREDPV(CopFILE(c))
 188 #else
 189 #  define SAVECOPSTASH(c)       SAVESPTR(CopSTASH(c))
 190 #  define SAVECOPSTASH_FREE(c)  SAVECOPSTASH(c) /* XXX not refcounted */
 191 #  define SAVECOPFILE(c)        SAVESPTR(CopFILEGV(c))
 192 #  define SAVECOPFILE_FREE(c)   SAVEGENERICSV(CopFILEGV(c))
 193 #endif
 194
 195 #define SAVECOPLINE(c)          SAVEI32(CopLINE(c))
 196
 197 /* SSNEW() temporarily allocates a specified number of bytes of data on the
 198  * savestack.  It returns an integer index into the savestack, because a
 199  * pointer would get broken if the savestack is moved on reallocation.
 200  * SSNEWa() works like SSNEW(), but also aligns the data to the specified
 201  * number of bytes.  MEM_ALIGNBYTES is perhaps the most useful.  The
 202  * alignment will be preserved therough savestack reallocation *only* if
 203  * realloc returns data aligned to a size divisible by `align'!
 204  *
 205  * SSPTR() converts the index returned by SSNEW/SSNEWa() into a pointer.
 206  */
 207
 208 #define SSNEW(size)             Perl_save_alloc(aTHX_ (size), 0)
 209 #define SSNEWt(n,t)             SSNEW((n)*sizeof(t))
 210 #define SSNEWa(size,align)      Perl_save_alloc(aTHX_ (size), \
 211     (align - ((int)((caddr_t)&PL_savestack[PL_savestack_ix]) % align)) % align)
 212 #define SSNEWat(n,t,align)      SSNEWa((n)*sizeof(t), align)
 213
 214 #define SSPTR(off,type)         ((type)  ((char*)PL_savestack + off))
 215 #define SSPTRt(off,type)        ((type*) ((char*)PL_savestack + off))
 216
 217 /* A jmpenv packages the state required to perform a proper non-local jump.
 218  * Note that there is a start_env initialized when perl starts, and top_env
 219  * points to this initially, so top_env should always be non-null.
 220  *
 221  * Existence of a non-null top_env->je_prev implies it is valid to call
 222  * longjmp() at that runlevel (we make sure start_env.je_prev is always
 223  * null to ensure this).
 224  *
 225  * je_mustcatch, when set at any runlevel to TRUE, means eval ops must
 226  * establish a local jmpenv to handle exception traps.  Care must be taken
 227  * to restore the previous value of je_mustcatch before exiting the
 228  * stack frame iff JMPENV_PUSH was not called in that stack frame.
 229  * GSAR 97-03-27
 230  */
 231
 232 struct jmpenv {
 233     struct jmpenv *     je_prev;
 234     Sigjmp_buf          je_buf;         /* only for use if !je_throw */
 235     int                 je_ret;         /* last exception thrown */
 236     bool                je_mustcatch;   /* need to call longjmp()? */
 237 };
 238
 239 typedef struct jmpenv JMPENV;
 240
 241 #ifdef OP_IN_REGISTER
 242 #define OP_REG_TO_MEM   PL_opsave = op
 243 #define OP_MEM_TO_REG   op = PL_opsave
 244 #else
 245 #define OP_REG_TO_MEM   NOOP
 246 #define OP_MEM_TO_REG   NOOP
 247 #endif
 248
 249 /*
 250  * How to build the first jmpenv.
 251  *
 252  * top_env needs to be non-zero. It points to an area
 253  * in which longjmp() stuff is stored, as C callstack
 254  * info there at least is thread specific this has to
 255  * be per-thread. Otherwise a 'die' in a thread gives
 256  * that thread the C stack of last thread to do an eval {}!
 257  */
 258
 259 #define JMPENV_BOOTSTRAP \
 260     STMT_START {                                \
 261         Zero(&PL_start_env, 1, JMPENV);         \
 262         PL_start_env.je_ret = -1;               \
 263         PL_start_env.je_mustcatch = TRUE;       \
 264         PL_top_env = &PL_start_env;             \
 265     } STMT_END
 266
 267 /*
 268  *   PERL_FLEXIBLE_EXCEPTIONS
 269  *
 270  * All the flexible exceptions code has been removed.
 271  * See the following threads for details:
 272  *
 273  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2004-07/msg00378.html
 274  *
 275  * Joshua's original patches (which weren't applied) and discussion:
 276  *
 277  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01396.html
 278  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01489.html
 279  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01491.html
 280  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg01608.html
 281  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg02144.html
 282  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1998-02/msg02998.html
 283  *
 284  * Chip's reworked patch and discussion:
 285  *
 286  *   http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/1999-03/msg00520.html
 287  *
 288  * The flaw in these patches (which went unnoticed at the time) was
 289  * that they moved some code that could potentially die() out of the
 290  * region protected by the setjmp()s.  This caused exceptions within
 291  * END blocks and such to not be handled by the correct setjmp().
 292  *
 293  * The original patches that introduces flexible exceptions were:
 294  *
 295  *   http://public.activestate.com/cgi-bin/perlbrowse?patch=3386
 296  *   http://public.activestate.com/cgi-bin/perlbrowse?patch=5162
 297  */
 298
 299 #define dJMPENV         JMPENV cur_env
 300
 301 #define JMPENV_PUSH(v) \
 302     STMT_START {                                                        \
 303         DEBUG_l(Perl_deb(aTHX_ "Setting up jumplevel %p, was %p\n",     \
 304                          &cur_env, PL_top_env));                        \
 305         cur_env.je_prev = PL_top_env;                                   \
 306         OP_REG_TO_MEM;                                                  \
 307         cur_env.je_ret = PerlProc_setjmp(cur_env.je_buf, SCOPE_SAVES_SIGNAL_MASK);              \
 308         OP_MEM_TO_REG;                                                  \
 309         PL_top_env = &cur_env;                                          \
 310         cur_env.je_mustcatch = FALSE;                                   \
 311         (v) = cur_env.je_ret;                                           \
 312     } STMT_END
 313
 314 #define JMPENV_POP \
 315     STMT_START {                                                        \
 316         DEBUG_l(Perl_deb(aTHX_ "popping jumplevel was %p, now %p\n",    \
 317                          PL_top_env, cur_env.je_prev));                 \
 318         PL_top_env = cur_env.je_prev;                                   \
 319     } STMT_END
 320
 321 #define JMPENV_JUMP(v) \
 322     STMT_START {                                                \
 323         OP_REG_TO_MEM;                                          \
 324         if (PL_top_env->je_prev)                                \
 325             PerlProc_longjmp(PL_top_env->je_buf, (v));          \
 326         if ((v) == 2)                                           \
 327             PerlProc_exit(STATUS_NATIVE_EXPORT);                \
 328         PerlIO_printf(PerlIO_stderr(), "panic: top_env\n");     \
 329         PerlProc_exit(1);                                       \
 330     } STMT_END
 331
 332 #define CATCH_GET               (PL_top_env->je_mustcatch)
 333 #define CATCH_SET(v)            (PL_top_env->je_mustcatch = (v))