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[/] [openrisc/] [trunk/] [gnu-stable/] [gcc-4.5.1/] [gcc/] [except.h] - Blame information for rev 826

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1 280 jeremybenn
/* Exception Handling interface routines.
2
   Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
3
   2007, 2008, 2009  Free Software Foundation, Inc.
4
   Contributed by Mike Stump <mrs@cygnus.com>.
5
 
6
This file is part of GCC.
7
 
8
GCC is free software; you can redistribute it and/or modify it under
9
the terms of the GNU General Public License as published by the Free
10
Software Foundation; either version 3, or (at your option) any later
11
version.
12
 
13
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14
WARRANTY; without even the implied warranty of MERCHANTABILITY or
15
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
16
for more details.
17
 
18
You should have received a copy of the GNU General Public License
19
along with GCC; see the file COPYING3.  If not see
20
<http://www.gnu.org/licenses/>.  */
21
 
22
#include "sbitmap.h"
23
#include "vecprim.h"
24
 
25
struct function;
26
struct eh_region_d;
27
struct pointer_map_t;
28
 
29
/* The type of an exception region.  */
30
enum eh_region_type
31
{
32
  /* CLEANUP regions implement e.g. destructors run when exiting a block.
33
     They can be generated from both GIMPLE_TRY_FINALLY and GIMPLE_TRY_CATCH
34
     nodes.  It is expected by the runtime that cleanup regions will *not*
35
     resume normal program flow, but will continue propagation of the
36
     exception.  */
37
  ERT_CLEANUP,
38
 
39
  /* TRY regions implement catching an exception.  The list of types associated
40
     with the attached catch handlers is examined in order by the runtime and
41
     control is transfered to the appropriate handler.  Note that a NULL type
42
     list is a catch-all handler, and that it will catch *all* exceptions
43
     including those originating from a different language.  */
44
  ERT_TRY,
45
 
46
  /* ALLOWED_EXCEPTIONS regions implement exception filtering, e.g. the
47
     throw(type-list) specification that can be added to C++ functions.
48
     The runtime examines the thrown exception vs the type list, and if
49
     the exception does not match, transfers control to the handler.  The
50
     normal handler for C++ calls __cxa_call_unexpected.  */
51
  ERT_ALLOWED_EXCEPTIONS,
52
 
53
  /* MUST_NOT_THROW regions prevent all exceptions from propagating.  This
54
     region type is used in C++ to surround destructors being run inside a
55
     CLEANUP region.  This differs from an ALLOWED_EXCEPTIONS region with
56
     an empty type list in that the runtime is prepared to terminate the
57
     program directly.  We only generate code for MUST_NOT_THROW regions
58
     along control paths that are already handling an exception within the
59
     current function.  */
60
  ERT_MUST_NOT_THROW
61
};
62
 
63
 
64
/* A landing pad for a given exception region.  Any transfer of control
65
   from the EH runtime to the function happens at a landing pad.  */
66
 
67
struct GTY(()) eh_landing_pad_d
68
{
69
  /* The linked list of all landing pads associated with the region.  */
70
  struct eh_landing_pad_d *next_lp;
71
 
72
  /* The region with which this landing pad is associated.  */
73
  struct eh_region_d *region;
74
 
75
  /* At the gimple level, the location to which control will be transfered
76
     for this landing pad.  There can be both EH and normal edges into the
77
     block containing the post-landing-pad label.  */
78
  tree post_landing_pad;
79
 
80
  /* At the rtl level, the location to which the runtime will transfer
81
     control.  This differs from the post-landing-pad in that the target's
82
     EXCEPTION_RECEIVER pattern will be expanded here, as well as other
83
     bookkeeping specific to exceptions.  There must not be normal edges
84
     into the block containing the landing-pad label.  */
85
  rtx landing_pad;
86
 
87
  /* The index of this landing pad within fun->eh->lp_array.  */
88
  int index;
89
};
90
 
91
/* A catch handler associated with an ERT_TRY region.  */
92
 
93
struct GTY(()) eh_catch_d
94
{
95
  /* The double-linked list of all catch handlers for the region.  */
96
  struct eh_catch_d *next_catch;
97
  struct eh_catch_d *prev_catch;
98
 
99
  /* A TREE_LIST of runtime type objects that this catch handler
100
     will catch, or NULL if all exceptions are caught.  */
101
  tree type_list;
102
 
103
  /* A TREE_LIST of INTEGER_CSTs that correspond to the type_list entries,
104
     having been mapped by assign_filter_values.  These integers are to be
105
     compared against the __builtin_eh_filter value.  */
106
  tree filter_list;
107
 
108
  /* The code that should be executed if this catch handler matches the
109
     thrown exception.  This label is only maintained until
110
     pass_lower_eh_dispatch, at which point it is cleared.  */
111
  tree label;
112
};
113
 
114
/* Describes one exception region.  */
115
 
116
struct GTY(()) eh_region_d
117
{
118
  /* The immediately surrounding region.  */
119
  struct eh_region_d *outer;
120
 
121
  /* The list of immediately contained regions.  */
122
  struct eh_region_d *inner;
123
  struct eh_region_d *next_peer;
124
 
125
  /* The index of this region within fun->eh->region_array.  */
126
  int index;
127
 
128
  /* Each region does exactly one thing.  */
129
  enum eh_region_type type;
130
 
131
  /* Holds the action to perform based on the preceding type.  */
132
  union eh_region_u {
133
    struct eh_region_u_try {
134
      /* The double-linked list of all catch handlers for this region.  */
135
      struct eh_catch_d *first_catch;
136
      struct eh_catch_d *last_catch;
137
    } GTY ((tag ("ERT_TRY"))) eh_try;
138
 
139
    struct eh_region_u_allowed {
140
      /* A TREE_LIST of runtime type objects allowed to pass.  */
141
      tree type_list;
142
      /* The code that should be executed if the thrown exception does
143
         not match the type list.  This label is only maintained until
144
         pass_lower_eh_dispatch, at which point it is cleared.  */
145
      tree label;
146
      /* The integer that will be passed by the runtime to signal that
147
         we should execute the code at LABEL.  This integer is assigned
148
         by assign_filter_values and is to be compared against the
149
         __builtin_eh_filter value.  */
150
      int filter;
151
    } GTY ((tag ("ERT_ALLOWED_EXCEPTIONS"))) allowed;
152
 
153
    struct eh_region_u_must_not_throw {
154
      /* A function decl to be invoked if this region is actually reachable
155
         from within the function, rather than implementable from the runtime.
156
         The normal way for this to happen is for there to be a CLEANUP region
157
         contained within this MUST_NOT_THROW region.  Note that if the
158
         runtime handles the MUST_NOT_THROW region, we have no control over
159
         what termination function is called; it will be decided by the
160
         personality function in effect for this CIE.  */
161
      tree failure_decl;
162
      /* The location assigned to the call of FAILURE_DECL, if expanded.  */
163
      location_t failure_loc;
164
    } GTY ((tag ("ERT_MUST_NOT_THROW"))) must_not_throw;
165
  } GTY ((desc ("%0.type"))) u;
166
 
167
  /* The list of landing pads associated with this region.  */
168
  struct eh_landing_pad_d *landing_pads;
169
 
170
  /* EXC_PTR and FILTER values copied from the runtime for this region.
171
     Each region gets its own psuedos so that if there are nested exceptions
172
     we do not overwrite the values of the first exception.  */
173
  rtx exc_ptr_reg, filter_reg;
174
 
175
  /* True if this region should use __cxa_end_cleanup instead
176
     of _Unwind_Resume.  */
177
  bool use_cxa_end_cleanup;
178
};
179
 
180
typedef struct eh_landing_pad_d *eh_landing_pad;
181
typedef struct eh_catch_d *eh_catch;
182
typedef struct eh_region_d *eh_region;
183
 
184
DEF_VEC_P(eh_region);
185
DEF_VEC_ALLOC_P(eh_region, gc);
186
DEF_VEC_ALLOC_P(eh_region, heap);
187
 
188
DEF_VEC_P(eh_landing_pad);
189
DEF_VEC_ALLOC_P(eh_landing_pad, gc);
190
 
191
 
192
/* The exception status for each function.  */
193
 
194
struct GTY(()) eh_status
195
{
196
  /* The tree of all regions for this function.  */
197
  eh_region region_tree;
198
 
199
  /* The same information as an indexable array.  */
200
  VEC(eh_region,gc) *region_array;
201
 
202
  /* The landing pads as an indexable array.  */
203
  VEC(eh_landing_pad,gc) *lp_array;
204
 
205
  /* At the gimple level, a mapping from gimple statement to landing pad
206
     or must-not-throw region.  See record_stmt_eh_region.  */
207
  htab_t GTY((param_is (struct throw_stmt_node))) throw_stmt_table;
208
 
209
  /* All of the runtime type data used by the function.  These objects
210
     are emitted to the lang-specific-data-area for the function.  */
211
  VEC(tree,gc) *ttype_data;
212
 
213
  /* The table of all action chains.  These encode the eh_region tree in
214
     a compact form for use by the runtime, and is also emitted to the
215
     lang-specific-data-area.  Note that the ARM EABI uses a different
216
     format for the encoding than all other ports.  */
217
  union eh_status_u {
218
    VEC(tree,gc) * GTY((tag ("1"))) arm_eabi;
219
    VEC(uchar,gc) * GTY((tag ("0"))) other;
220
  } GTY ((desc ("targetm.arm_eabi_unwinder"))) ehspec_data;
221
};
222
 
223
 
224
/* Test: is exception handling turned on?  */
225
extern int doing_eh (int);
226
 
227
/* Invokes CALLBACK for every exception handler label.  Only used by old
228
   loop hackery; should not be used by new code.  */
229
extern void for_each_eh_label (void (*) (rtx));
230
 
231
extern void init_eh (void);
232
extern void init_eh_for_function (void);
233
 
234
extern void remove_eh_landing_pad (eh_landing_pad);
235
extern void remove_eh_handler (eh_region);
236
 
237
extern bool current_function_has_exception_handlers (void);
238
extern void output_function_exception_table (const char *);
239
 
240
extern rtx expand_builtin_eh_pointer (tree);
241
extern rtx expand_builtin_eh_filter (tree);
242
extern rtx expand_builtin_eh_copy_values (tree);
243
extern void expand_builtin_unwind_init (void);
244
extern rtx expand_builtin_eh_return_data_regno (tree);
245
extern rtx expand_builtin_extract_return_addr (tree);
246
extern void expand_builtin_init_dwarf_reg_sizes (tree);
247
extern rtx expand_builtin_frob_return_addr (tree);
248
extern rtx expand_builtin_dwarf_sp_column (void);
249
extern void expand_builtin_eh_return (tree, tree);
250
extern void expand_eh_return (void);
251
extern rtx expand_builtin_extend_pointer (tree);
252
 
253
typedef tree (*duplicate_eh_regions_map) (tree, void *);
254
extern struct pointer_map_t *duplicate_eh_regions
255
  (struct function *, eh_region, int, duplicate_eh_regions_map, void *);
256
 
257
extern void sjlj_emit_function_exit_after (rtx);
258
 
259
extern eh_region gen_eh_region_cleanup (eh_region);
260
extern eh_region gen_eh_region_try (eh_region);
261
extern eh_region gen_eh_region_allowed (eh_region, tree);
262
extern eh_region gen_eh_region_must_not_throw (eh_region);
263
 
264
extern eh_catch gen_eh_region_catch (eh_region, tree);
265
extern eh_landing_pad gen_eh_landing_pad (eh_region);
266
 
267
extern eh_region get_eh_region_from_number_fn (struct function *, int);
268
extern eh_region get_eh_region_from_number (int);
269
extern eh_landing_pad get_eh_landing_pad_from_number_fn (struct function*,int);
270
extern eh_landing_pad get_eh_landing_pad_from_number (int);
271
extern eh_region get_eh_region_from_lp_number_fn (struct function *, int);
272
extern eh_region get_eh_region_from_lp_number (int);
273
 
274
extern eh_region eh_region_outermost (struct function *, eh_region, eh_region);
275
 
276
extern void make_reg_eh_region_note (rtx insn, int ecf_flags, int lp_nr);
277
extern void make_reg_eh_region_note_nothrow_nononlocal (rtx);
278
 
279
extern void verify_eh_tree (struct function *);
280
extern void dump_eh_tree (FILE *, struct function *);
281
void debug_eh_tree (struct function *);
282
extern void add_type_for_runtime (tree);
283
extern tree lookup_type_for_runtime (tree);
284
extern void assign_filter_values (void);
285
 
286
extern eh_region get_eh_region_from_rtx (const_rtx);
287
extern eh_landing_pad get_eh_landing_pad_from_rtx (const_rtx);
288
 
289
/* If non-NULL, this is a function that returns a function decl to be
290
   executed if an unhandled exception is propagated out of a cleanup
291
   region.  For example, in C++, an exception thrown by a destructor
292
   during stack unwinding is required to result in a call to
293
   `std::terminate', so the C++ version of this function returns a
294
   FUNCTION_DECL for `std::terminate'.  */
295
extern tree (*lang_protect_cleanup_actions) (void);
296
 
297
/* Return true if type A catches type B.  */
298
extern int (*lang_eh_type_covers) (tree a, tree b);
299
 
300
 
301
/* Just because the user configured --with-sjlj-exceptions=no doesn't
302
   mean that we can use call frame exceptions.  Detect that the target
303
   has appropriate support.  */
304
 
305
#ifndef MUST_USE_SJLJ_EXCEPTIONS
306
# if defined (EH_RETURN_DATA_REGNO)                     \
307
       && (defined (TARGET_UNWIND_INFO)                 \
308
           || (DWARF2_UNWIND_INFO                       \
309
               && (defined (EH_RETURN_HANDLER_RTX)      \
310
                   || defined (HAVE_eh_return))))
311
#  define MUST_USE_SJLJ_EXCEPTIONS      0
312
# else
313
#  define MUST_USE_SJLJ_EXCEPTIONS      1
314
# endif
315
#endif
316
 
317
#ifdef CONFIG_SJLJ_EXCEPTIONS
318
# if CONFIG_SJLJ_EXCEPTIONS == 1
319
#  define USING_SJLJ_EXCEPTIONS         1
320
# endif
321
# if CONFIG_SJLJ_EXCEPTIONS == 0
322
#  define USING_SJLJ_EXCEPTIONS         0
323
#  if !defined(EH_RETURN_DATA_REGNO)
324
    #error "EH_RETURN_DATA_REGNO required"
325
#  endif
326
#  if ! (defined(TARGET_UNWIND_INFO) || DWARF2_UNWIND_INFO)
327
    #error "{DWARF2,TARGET}_UNWIND_INFO required"
328
#  endif
329
#  if !defined(TARGET_UNWIND_INFO) \
330
        && !(defined(EH_RETURN_HANDLER_RTX) || defined(HAVE_eh_return))
331
    #error "EH_RETURN_HANDLER_RTX or eh_return required"
332
#  endif
333
/* Usually the above error checks will have already triggered an
334
   error, but backends may set MUST_USE_SJLJ_EXCEPTIONS for their own
335
   reasons.  */
336
#  if MUST_USE_SJLJ_EXCEPTIONS
337
    #error "Must use SJLJ exceptions but configured not to"
338
#  endif
339
# endif
340
#else
341
# define USING_SJLJ_EXCEPTIONS          MUST_USE_SJLJ_EXCEPTIONS
342
#endif
343
 
344
struct GTY(()) throw_stmt_node {
345
  gimple stmt;
346
  int lp_nr;
347
};
348
 
349
extern struct htab *get_eh_throw_stmt_table (struct function *);
350
extern void set_eh_throw_stmt_table (struct function *, struct htab *);
351
 
352
enum eh_personality_kind {
353
  eh_personality_none,
354
  eh_personality_any,
355
  eh_personality_lang
356
};
357
 
358
extern enum eh_personality_kind
359
function_needs_eh_personality (struct function *);
360
 
361
/* Pre-order iteration within the eh_region tree.  */
362
 
363
static inline eh_region
364
ehr_next (eh_region r, eh_region start)
365
{
366
  if (r->inner)
367
    r = r->inner;
368
  else if (r->next_peer && r != start)
369
    r = r->next_peer;
370
  else
371
    {
372
      do
373
        {
374
          r = r->outer;
375
          if (r == start)
376
            return NULL;
377
        }
378
      while (r->next_peer == NULL);
379
      r = r->next_peer;
380
    }
381
  return r;
382
}
383
 
384
#define FOR_ALL_EH_REGION_AT(R, START) \
385
  for ((R) = (START); (R) != NULL; (R) = ehr_next (R, START))
386
 
387
#define FOR_ALL_EH_REGION_FN(R, FN) \
388
  for ((R) = (FN)->eh->region_tree; (R) != NULL; (R) = ehr_next (R, NULL))
389
 
390
#define FOR_ALL_EH_REGION(R) FOR_ALL_EH_REGION_FN (R, cfun)

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