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