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[perl #24914] freeing a CV reference that was currently being
[perl5.git] / scope.h
1 /*    scope.h
2  *
3  *    Copyright (C) 1993, 1994, 1996, 1997, 1998, 1999,
4  *    2000, 2001, 2002, 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
52 #ifndef SCOPE_SAVES_SIGNAL_MASK
53 #define SCOPE_SAVES_SIGNAL_MASK 0
54 #endif
55
56 #define SSCHECK(need) if (PL_savestack_ix + (need) > PL_savestack_max) savestack_grow()
57 #define SSGROW(need) if (PL_savestack_ix + (need) > PL_savestack_max) savestack_grow_cnt(need)
58 #define SSPUSHINT(i) (PL_savestack[PL_savestack_ix++].any_i32 = (I32)(i))
59 #define SSPUSHLONG(i) (PL_savestack[PL_savestack_ix++].any_long = (long)(i))
60 #define SSPUSHBOOL(p) (PL_savestack[PL_savestack_ix++].any_bool = (p))
61 #define SSPUSHIV(i) (PL_savestack[PL_savestack_ix++].any_iv = (IV)(i))
62 #define SSPUSHPTR(p) (PL_savestack[PL_savestack_ix++].any_ptr = (void*)(p))
63 #define SSPUSHDPTR(p) (PL_savestack[PL_savestack_ix++].any_dptr = (p))
64 #define SSPUSHDXPTR(p) (PL_savestack[PL_savestack_ix++].any_dxptr = (p))
65 #define SSPOPINT (PL_savestack[--PL_savestack_ix].any_i32)
66 #define SSPOPLONG (PL_savestack[--PL_savestack_ix].any_long)
67 #define SSPOPBOOL (PL_savestack[--PL_savestack_ix].any_bool)
68 #define SSPOPIV (PL_savestack[--PL_savestack_ix].any_iv)
69 #define SSPOPPTR (PL_savestack[--PL_savestack_ix].any_ptr)
70 #define SSPOPDPTR (PL_savestack[--PL_savestack_ix].any_dptr)
71 #define SSPOPDXPTR (PL_savestack[--PL_savestack_ix].any_dxptr)
72
73 /*
74 =head1 Callback Functions
75
76 =for apidoc Ams||SAVETMPS
77 Opening bracket for temporaries on a callback.  See C<FREETMPS> and
78 L<perlcall>.
79
80 =for apidoc Ams||FREETMPS
81 Closing bracket for temporaries on a callback.  See C<SAVETMPS> and
82 L<perlcall>.
83
84 =for apidoc Ams||ENTER
85 Opening bracket on a callback.  See C<LEAVE> and L<perlcall>.
86
87 =for apidoc Ams||LEAVE
88 Closing bracket on a callback.  See C<ENTER> and L<perlcall>.
89
90 =cut
91 */
92
93 #define SAVETMPS save_int((int*)&PL_tmps_floor), PL_tmps_floor = PL_tmps_ix
94 #define FREETMPS if (PL_tmps_ix > PL_tmps_floor) free_tmps()
95
96 #ifdef DEBUGGING
97 #define ENTER                                                   \
98     STMT_START {                                                \
99         push_scope();                                           \
100         DEBUG_SCOPE("ENTER")                                    \
101     } STMT_END
102 #define LEAVE                                                   \
103     STMT_START {                                                \
104         DEBUG_SCOPE("LEAVE")                                    \
105         pop_scope();                                            \
106     } STMT_END
107 #else
108 #define ENTER push_scope()
109 #define LEAVE pop_scope()
110 #endif
111 #define LEAVE_SCOPE(old) if (PL_savestack_ix > old) leave_scope(old)
112
113 /*
114  * Not using SOFT_CAST on SAVESPTR, SAVEGENERICSV and SAVEFREESV
115  * because these are used for several kinds of pointer values
116  */
117 #define SAVEI8(i)       save_I8(SOFT_CAST(I8*)&(i))
118 #define SAVEI16(i)      save_I16(SOFT_CAST(I16*)&(i))
119 #define SAVEI32(i)      save_I32(SOFT_CAST(I32*)&(i))
120 #define SAVEINT(i)      save_int(SOFT_CAST(int*)&(i))
121 #define SAVEIV(i)       save_iv(SOFT_CAST(IV*)&(i))
122 #define SAVELONG(l)     save_long(SOFT_CAST(long*)&(l))
123 #define SAVEBOOL(b)     save_bool(SOFT_CAST(bool*)&(b))
124 #define SAVESPTR(s)     save_sptr((SV**)&(s))
125 #define SAVEPPTR(s)     save_pptr(SOFT_CAST(char**)&(s))
126 #define SAVEVPTR(s)     save_vptr((void*)&(s))
127 #define SAVEPADSV(s)    save_padsv(s)
128 #define SAVEFREESV(s)   save_freesv((SV*)(s))
129 #define SAVEMORTALIZESV(s)      save_mortalizesv((SV*)(s))
130 #define SAVEFREEOP(o)   save_freeop(SOFT_CAST(OP*)(o))
131 #define SAVEFREEPV(p)   save_freepv(SOFT_CAST(char*)(p))
132 #define SAVECLEARSV(sv) save_clearsv(SOFT_CAST(SV**)&(sv))
133 #define SAVEGENERICSV(s)        save_generic_svref((SV**)&(s))
134 #define SAVEGENERICPV(s)        save_generic_pvref((char**)&(s))
135 #define SAVESHAREDPV(s)         save_shared_pvref((char**)&(s))
136 #define SAVESETSVFLAGS(sv,mask,val)     save_set_svflags(sv,mask,val)
137 #define SAVEDELETE(h,k,l) \
138           save_delete(SOFT_CAST(HV*)(h), SOFT_CAST(char*)(k), (I32)(l))
139 #define SAVEDESTRUCTOR(f,p) \
140           save_destructor((DESTRUCTORFUNC_NOCONTEXT_t)(f), SOFT_CAST(void*)(p))
141
142 #define SAVEDESTRUCTOR_X(f,p) \
143           save_destructor_x((DESTRUCTORFUNC_t)(f), SOFT_CAST(void*)(p))
144
145 #define SAVESTACK_POS() \
146     STMT_START {                                \
147         SSCHECK(2);                             \
148         SSPUSHINT(PL_stack_sp - PL_stack_base); \
149         SSPUSHINT(SAVEt_STACK_POS);             \
150     } STMT_END
151
152 #define SAVEOP()        save_op()
153
154 #define SAVEHINTS() \
155     STMT_START {                                \
156         if (PL_hints & HINT_LOCALIZE_HH)        \
157             save_hints();                       \
158         else {                                  \
159             SSCHECK(2);                         \
160             SSPUSHINT(PL_hints);                \
161             SSPUSHINT(SAVEt_HINTS);             \
162         }                                       \
163     } STMT_END
164
165 #define SAVECOMPPAD() \
166     STMT_START {                                                \
167         SSCHECK(2);                                             \
168         SSPUSHPTR((SV*)PL_comppad);                             \
169         SSPUSHINT(SAVEt_COMPPAD);                               \
170         SvREFCNT_inc(PL_comppad);                               \
171     } STMT_END
172
173 #ifdef USE_ITHREADS
174 #  define SAVECOPSTASH(c)       SAVEPPTR(CopSTASHPV(c))
175 #  define SAVECOPSTASH_FREE(c)  SAVESHAREDPV(CopSTASHPV(c))
176 #  define SAVECOPFILE(c)        SAVEPPTR(CopFILE(c))
177 #  define SAVECOPFILE_FREE(c)   SAVESHAREDPV(CopFILE(c))
178 #else
179 #  define SAVECOPSTASH(c)       SAVESPTR(CopSTASH(c))
180 #  define SAVECOPSTASH_FREE(c)  SAVECOPSTASH(c) /* XXX not refcounted */
181 #  define SAVECOPFILE(c)        SAVESPTR(CopFILEGV(c))
182 #  define SAVECOPFILE_FREE(c)   SAVEGENERICSV(CopFILEGV(c))
183 #endif
184
185 #define SAVECOPLINE(c)          SAVEI32(CopLINE(c))
186
187 /* SSNEW() temporarily allocates a specified number of bytes of data on the
188  * savestack.  It returns an integer index into the savestack, because a
189  * pointer would get broken if the savestack is moved on reallocation.
190  * SSNEWa() works like SSNEW(), but also aligns the data to the specified
191  * number of bytes.  MEM_ALIGNBYTES is perhaps the most useful.  The
192  * alignment will be preserved therough savestack reallocation *only* if
193  * realloc returns data aligned to a size divisible by `align'!
194  *
195  * SSPTR() converts the index returned by SSNEW/SSNEWa() into a pointer.
196  */
197
198 #define SSNEW(size)             Perl_save_alloc(aTHX_ (size), 0)
199 #define SSNEWt(n,t)             SSNEW((n)*sizeof(t))
200 #define SSNEWa(size,align)      Perl_save_alloc(aTHX_ (size), \
201     (align - ((int)((caddr_t)&PL_savestack[PL_savestack_ix]) % align)) % align)
202 #define SSNEWat(n,t,align)      SSNEWa((n)*sizeof(t), align)
203
204 #define SSPTR(off,type)         ((type)  ((char*)PL_savestack + off))
205 #define SSPTRt(off,type)        ((type*) ((char*)PL_savestack + off))
206
207 /* A jmpenv packages the state required to perform a proper non-local jump.
208  * Note that there is a start_env initialized when perl starts, and top_env
209  * points to this initially, so top_env should always be non-null.
210  *
211  * Existence of a non-null top_env->je_prev implies it is valid to call
212  * longjmp() at that runlevel (we make sure start_env.je_prev is always
213  * null to ensure this).
214  *
215  * je_mustcatch, when set at any runlevel to TRUE, means eval ops must
216  * establish a local jmpenv to handle exception traps.  Care must be taken
217  * to restore the previous value of je_mustcatch before exiting the
218  * stack frame iff JMPENV_PUSH was not called in that stack frame.
219  * GSAR 97-03-27
220  */
221
222 struct jmpenv {
223     struct jmpenv *     je_prev;
224     Sigjmp_buf          je_buf;         /* only for use if !je_throw */
225     int                 je_ret;         /* last exception thrown */
226     bool                je_mustcatch;   /* need to call longjmp()? */
227 #ifdef PERL_FLEXIBLE_EXCEPTIONS
228     void                (*je_throw)(int v); /* last for bincompat */
229     bool                je_noset;       /* no need for setjmp() */
230 #endif
231 };
232
233 typedef struct jmpenv JMPENV;
234
235 #ifdef OP_IN_REGISTER
236 #define OP_REG_TO_MEM   PL_opsave = op
237 #define OP_MEM_TO_REG   op = PL_opsave
238 #else
239 #define OP_REG_TO_MEM   NOOP
240 #define OP_MEM_TO_REG   NOOP
241 #endif
242
243 /*
244  * How to build the first jmpenv.
245  *
246  * top_env needs to be non-zero. It points to an area
247  * in which longjmp() stuff is stored, as C callstack
248  * info there at least is thread specific this has to
249  * be per-thread. Otherwise a 'die' in a thread gives
250  * that thread the C stack of last thread to do an eval {}!
251  */
252
253 #define JMPENV_BOOTSTRAP \
254     STMT_START {                                \
255         Zero(&PL_start_env, 1, JMPENV);         \
256         PL_start_env.je_ret = -1;               \
257         PL_start_env.je_mustcatch = TRUE;       \
258         PL_top_env = &PL_start_env;             \
259     } STMT_END
260
261 #ifdef PERL_FLEXIBLE_EXCEPTIONS
262
263 /*
264  * These exception-handling macros are split up to
265  * ease integration with C++ exceptions.
266  *
267  * To use C++ try+catch to catch Perl exceptions, an extension author
268  * needs to first write an extern "C" function to throw an appropriate
269  * exception object; typically it will be or contain an integer,
270  * because Perl's internals use integers to track exception types:
271  *    extern "C" { static void thrower(int i) { throw i; } }
272  *
273  * Then (as shown below) the author needs to use, not the simple
274  * JMPENV_PUSH, but several of its constitutent macros, to arrange for
275  * the Perl internals to call thrower() rather than longjmp() to
276  * report exceptions:
277  *
278  *    dJMPENV;
279  *    JMPENV_PUSH_INIT(thrower);
280  *    try {
281  *        ... stuff that may throw exceptions ...
282  *    }
283  *    catch (int why) {  // or whatever matches thrower()
284  *        JMPENV_POST_CATCH;
285  *        EXCEPT_SET(why);
286  *        switch (why) {
287  *          ... // handle various Perl exception codes
288  *        }
289  *    }
290  *    JMPENV_POP;  // don't forget this!
291  */
292
293 /*
294  * Function that catches/throws, and its callback for the
295  *  body of protected processing.
296  */
297 typedef void *(CPERLscope(*protect_body_t)) (pTHX_ va_list);
298 typedef void *(CPERLscope(*protect_proc_t)) (pTHX_ volatile JMPENV *pcur_env,
299                                              int *, protect_body_t, ...);
300
301 #define dJMPENV JMPENV cur_env; \
302                 volatile JMPENV *pcur_env = ((cur_env.je_noset = 0),&cur_env)
303
304 #define JMPENV_PUSH_INIT_ENV(ce,THROWFUNC) \
305     STMT_START {                                        \
306         (ce).je_throw = (THROWFUNC);                    \
307         (ce).je_ret = -1;                               \
308         (ce).je_mustcatch = FALSE;                      \
309         (ce).je_prev = PL_top_env;                      \
310         PL_top_env = &(ce);                             \
311         OP_REG_TO_MEM;                                  \
312     } STMT_END
313
314 #define JMPENV_PUSH_INIT(THROWFUNC) JMPENV_PUSH_INIT_ENV(*(JMPENV*)pcur_env,THROWFUNC)
315
316 #define JMPENV_POST_CATCH_ENV(ce) \
317     STMT_START {                                        \
318         OP_MEM_TO_REG;                                  \
319         PL_top_env = &(ce);                             \
320     } STMT_END
321
322 #define JMPENV_POST_CATCH JMPENV_POST_CATCH_ENV(*(JMPENV*)pcur_env)
323
324 #define JMPENV_PUSH_ENV(ce,v) \
325     STMT_START {                                                \
326         if (!(ce).je_noset) {                                   \
327             DEBUG_l(Perl_deb(aTHX_ "Setting up jumplevel %p, was %p\n", \
328                              ce, PL_top_env));                  \
329             JMPENV_PUSH_INIT_ENV(ce,NULL);                      \
330             EXCEPT_SET_ENV(ce,PerlProc_setjmp((ce).je_buf, SCOPE_SAVES_SIGNAL_MASK));\
331             (ce).je_noset = 1;                                  \
332         }                                                       \
333         else                                                    \
334             EXCEPT_SET_ENV(ce,0);                               \
335         JMPENV_POST_CATCH_ENV(ce);                              \
336         (v) = EXCEPT_GET_ENV(ce);                               \
337     } STMT_END
338
339 #define JMPENV_PUSH(v) JMPENV_PUSH_ENV(*(JMPENV*)pcur_env,v)
340
341 #define JMPENV_POP_ENV(ce) \
342     STMT_START {                                                \
343         if (PL_top_env == &(ce))                                \
344             PL_top_env = (ce).je_prev;                          \
345     } STMT_END
346
347 #define JMPENV_POP  JMPENV_POP_ENV(*(JMPENV*)pcur_env)
348
349 #define JMPENV_JUMP(v) \
350     STMT_START {                                                \
351         OP_REG_TO_MEM;                                          \
352         if (PL_top_env->je_prev) {                              \
353             if (PL_top_env->je_throw)                           \
354                 PL_top_env->je_throw(v);                        \
355             else                                                \
356                 PerlProc_longjmp(PL_top_env->je_buf, (v));      \
357         }                                                       \
358         if ((v) == 2)                                           \
359             PerlProc_exit(STATUS_NATIVE_EXPORT);                \
360         PerlIO_printf(Perl_error_log, "panic: top_env\n");      \
361         PerlProc_exit(1);                                       \
362     } STMT_END
363
364 #define EXCEPT_GET_ENV(ce)      ((ce).je_ret)
365 #define EXCEPT_GET              EXCEPT_GET_ENV(*(JMPENV*)pcur_env)
366 #define EXCEPT_SET_ENV(ce,v)    ((ce).je_ret = (v))
367 #define EXCEPT_SET(v)           EXCEPT_SET_ENV(*(JMPENV*)pcur_env,v)
368
369 #else /* !PERL_FLEXIBLE_EXCEPTIONS */
370
371 #define dJMPENV         JMPENV cur_env
372
373 #define JMPENV_PUSH(v) \
374     STMT_START {                                                        \
375         DEBUG_l(Perl_deb(aTHX_ "Setting up jumplevel %p, was %p\n",     \
376                          &cur_env, PL_top_env));                        \
377         cur_env.je_prev = PL_top_env;                                   \
378         OP_REG_TO_MEM;                                                  \
379         cur_env.je_ret = PerlProc_setjmp(cur_env.je_buf, SCOPE_SAVES_SIGNAL_MASK);              \
380         OP_MEM_TO_REG;                                                  \
381         PL_top_env = &cur_env;                                          \
382         cur_env.je_mustcatch = FALSE;                                   \
383         (v) = cur_env.je_ret;                                           \
384     } STMT_END
385
386 #define JMPENV_POP \
387     STMT_START { PL_top_env = cur_env.je_prev; } STMT_END
388
389 #define JMPENV_JUMP(v) \
390     STMT_START {                                                \
391         OP_REG_TO_MEM;                                          \
392         if (PL_top_env->je_prev)                                \
393             PerlProc_longjmp(PL_top_env->je_buf, (v));          \
394         if ((v) == 2)                                           \
395             PerlProc_exit(STATUS_NATIVE_EXPORT);                \
396         PerlIO_printf(PerlIO_stderr(), "panic: top_env\n");     \
397         PerlProc_exit(1);                                       \
398     } STMT_END
399
400 #endif /* PERL_FLEXIBLE_EXCEPTIONS */
401
402 #define CATCH_GET               (PL_top_env->je_mustcatch)
403 #define CATCH_SET(v)            (PL_top_env->je_mustcatch = (v))