1 /* Everything about catch/throw catchpoints, for GDB.
3 Copyright (C) 1986-2015 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
21 #include "arch-utils.h"
23 #include "breakpoint.h"
28 #include "cli/cli-utils.h"
29 #include "completer.h"
30 #include "gdb_obstack.h"
31 #include "mi/mi-common.h"
36 #include "gdb_regex.h"
37 #include "cp-support.h"
39 /* Enums for exception-handling support. */
40 enum exception_event_kind
47 /* Each spot where we may place an exception-related catchpoint has
48 two names: the SDT probe point and the function name. This
49 structure holds both. */
51 struct exception_names
53 /* The name of the probe point to try, in the form accepted by
58 /* The name of the corresponding function. */
63 /* Names of the probe points and functions on which to break. This is
64 indexed by exception_event_kind. */
65 static const struct exception_names exception_functions
[] =
67 { "-probe-stap libstdcxx:throw", "__cxa_throw" },
68 { "-probe-stap libstdcxx:rethrow", "__cxa_rethrow" },
69 { "-probe-stap libstdcxx:catch", "__cxa_begin_catch" }
72 static struct breakpoint_ops gnu_v3_exception_catchpoint_ops
;
74 /* The type of an exception catchpoint. */
76 struct exception_catchpoint
80 struct breakpoint base
;
82 /* The kind of exception catchpoint. */
84 enum exception_event_kind kind
;
86 /* If non-NULL, an xmalloc'd string holding the source form of the
87 regular expression to match against. */
91 /* If non-NULL, an xmalloc'd, compiled regular expression which is
92 used to determine which exceptions to stop on. */
99 /* A helper function that fetches exception probe arguments. This
100 fills in *ARG0 (if non-NULL) and *ARG1 (which must be non-NULL).
101 It will throw an exception on any kind of failure. */
104 fetch_probe_arguments (struct value
**arg0
, struct value
**arg1
)
106 struct frame_info
*frame
= get_selected_frame (_("No frame selected"));
107 CORE_ADDR pc
= get_frame_pc (frame
);
108 struct bound_probe pc_probe
;
109 const struct sym_probe_fns
*pc_probe_fns
;
112 pc_probe
= find_probe_by_pc (pc
);
113 if (pc_probe
.probe
== NULL
114 || strcmp (pc_probe
.probe
->provider
, "libstdcxx") != 0
115 || (strcmp (pc_probe
.probe
->name
, "catch") != 0
116 && strcmp (pc_probe
.probe
->name
, "throw") != 0
117 && strcmp (pc_probe
.probe
->name
, "rethrow") != 0))
118 error (_("not stopped at a C++ exception catchpoint"));
120 n_args
= get_probe_argument_count (pc_probe
.probe
, frame
);
122 error (_("C++ exception catchpoint has too few arguments"));
125 *arg0
= evaluate_probe_argument (pc_probe
.probe
, 0, frame
);
126 *arg1
= evaluate_probe_argument (pc_probe
.probe
, 1, frame
);
128 if ((arg0
!= NULL
&& *arg0
== NULL
) || *arg1
== NULL
)
129 error (_("error computing probe argument at c++ exception catchpoint"));
134 /* A helper function that returns a value indicating the kind of the
135 exception catchpoint B. */
137 static enum exception_event_kind
138 classify_exception_breakpoint (struct breakpoint
*b
)
140 struct exception_catchpoint
*cp
= (struct exception_catchpoint
*) b
;
145 /* Implement the 'dtor' method. */
148 dtor_exception_catchpoint (struct breakpoint
*self
)
150 struct exception_catchpoint
*cp
= (struct exception_catchpoint
*) self
;
152 xfree (cp
->exception_rx
);
153 if (cp
->pattern
!= NULL
)
154 regfree (cp
->pattern
);
155 bkpt_breakpoint_ops
.dtor (self
);
158 /* Implement the 'check_status' method. */
161 check_status_exception_catchpoint (struct bpstats
*bs
)
163 struct exception_catchpoint
*self
164 = (struct exception_catchpoint
*) bs
->breakpoint_at
;
165 char *type_name
= NULL
;
167 bkpt_breakpoint_ops
.check_status (bs
);
171 if (self
->pattern
== NULL
)
176 struct value
*typeinfo_arg
;
179 fetch_probe_arguments (NULL
, &typeinfo_arg
);
180 type_name
= cplus_typename_from_type_info (typeinfo_arg
);
182 canon
= cp_canonicalize_string (type_name
);
189 CATCH (e
, RETURN_MASK_ERROR
)
191 exception_print (gdb_stderr
, e
);
195 if (type_name
!= NULL
)
197 if (regexec (self
->pattern
, type_name
, 0, NULL
, 0) != 0)
204 /* Implement the 're_set' method. */
207 re_set_exception_catchpoint (struct breakpoint
*self
)
209 struct symtabs_and_lines sals
= {0};
210 struct symtabs_and_lines sals_end
= {0};
211 struct cleanup
*cleanup
;
212 enum exception_event_kind kind
= classify_exception_breakpoint (self
);
214 /* We first try to use the probe interface. */
217 char *spec
= ASTRDUP (exception_functions
[kind
].probe
);
219 sals
= parse_probes (&spec
, NULL
);
222 CATCH (e
, RETURN_MASK_ERROR
)
225 /* Using the probe interface failed. Let's fallback to the normal
229 char *spec
= ASTRDUP (exception_functions
[kind
].function
);
231 self
->ops
->decode_linespec (self
, &spec
, &sals
);
233 CATCH (ex
, RETURN_MASK_ERROR
)
235 /* NOT_FOUND_ERROR just means the breakpoint will be
236 pending, so let it through. */
237 if (ex
.error
!= NOT_FOUND_ERROR
)
238 throw_exception (ex
);
244 cleanup
= make_cleanup (xfree
, sals
.sals
);
245 update_breakpoint_locations (self
, sals
, sals_end
);
246 do_cleanups (cleanup
);
249 static enum print_stop_action
250 print_it_exception_catchpoint (bpstat bs
)
252 struct ui_out
*uiout
= current_uiout
;
253 struct breakpoint
*b
= bs
->breakpoint_at
;
255 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
257 annotate_catchpoint (b
->number
);
259 bp_temp
= b
->disposition
== disp_del
;
261 bp_temp
? "Temporary catchpoint "
263 if (!ui_out_is_mi_like_p (uiout
))
264 ui_out_field_int (uiout
, "bkptno", b
->number
);
266 (kind
== EX_EVENT_THROW
? " (exception thrown), "
267 : (kind
== EX_EVENT_CATCH
? " (exception caught), "
268 : " (exception rethrown), ")));
269 if (ui_out_is_mi_like_p (uiout
))
271 ui_out_field_string (uiout
, "reason",
272 async_reason_lookup (EXEC_ASYNC_BREAKPOINT_HIT
));
273 ui_out_field_string (uiout
, "disp", bpdisp_text (b
->disposition
));
274 ui_out_field_int (uiout
, "bkptno", b
->number
);
276 return PRINT_SRC_AND_LOC
;
280 print_one_exception_catchpoint (struct breakpoint
*b
,
281 struct bp_location
**last_loc
)
283 struct value_print_options opts
;
284 struct ui_out
*uiout
= current_uiout
;
285 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
287 get_user_print_options (&opts
);
288 if (opts
.addressprint
)
291 if (b
->loc
== NULL
|| b
->loc
->shlib_disabled
)
292 ui_out_field_string (uiout
, "addr", "<PENDING>");
294 ui_out_field_core_addr (uiout
, "addr",
295 b
->loc
->gdbarch
, b
->loc
->address
);
304 ui_out_field_string (uiout
, "what", "exception throw");
305 if (ui_out_is_mi_like_p (uiout
))
306 ui_out_field_string (uiout
, "catch-type", "throw");
309 case EX_EVENT_RETHROW
:
310 ui_out_field_string (uiout
, "what", "exception rethrow");
311 if (ui_out_is_mi_like_p (uiout
))
312 ui_out_field_string (uiout
, "catch-type", "rethrow");
316 ui_out_field_string (uiout
, "what", "exception catch");
317 if (ui_out_is_mi_like_p (uiout
))
318 ui_out_field_string (uiout
, "catch-type", "catch");
323 /* Implement the 'print_one_detail' method. */
326 print_one_detail_exception_catchpoint (const struct breakpoint
*b
,
327 struct ui_out
*uiout
)
329 const struct exception_catchpoint
*cp
330 = (const struct exception_catchpoint
*) b
;
332 if (cp
->exception_rx
!= NULL
)
334 ui_out_text (uiout
, _("\tmatching: "));
335 ui_out_field_string (uiout
, "regexp", cp
->exception_rx
);
336 ui_out_text (uiout
, "\n");
341 print_mention_exception_catchpoint (struct breakpoint
*b
)
343 struct ui_out
*uiout
= current_uiout
;
345 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
347 bp_temp
= b
->disposition
== disp_del
;
348 ui_out_text (uiout
, bp_temp
? _("Temporary catchpoint ")
350 ui_out_field_int (uiout
, "bkptno", b
->number
);
351 ui_out_text (uiout
, (kind
== EX_EVENT_THROW
? _(" (throw)")
352 : (kind
== EX_EVENT_CATCH
? _(" (catch)")
353 : _(" (rethrow)"))));
356 /* Implement the "print_recreate" breakpoint_ops method for throw and
357 catch catchpoints. */
360 print_recreate_exception_catchpoint (struct breakpoint
*b
,
364 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
366 bp_temp
= b
->disposition
== disp_del
;
367 fprintf_unfiltered (fp
, bp_temp
? "tcatch " : "catch ");
371 fprintf_unfiltered (fp
, "throw");
374 fprintf_unfiltered (fp
, "catch");
376 case EX_EVENT_RETHROW
:
377 fprintf_unfiltered (fp
, "rethrow");
380 print_recreate_thread (b
, fp
);
384 handle_gnu_v3_exceptions (int tempflag
, char *except_rx
, char *cond_string
,
385 enum exception_event_kind ex_event
, int from_tty
)
387 struct exception_catchpoint
*cp
;
388 struct cleanup
*cleanup
= make_cleanup (null_cleanup
, NULL
);
389 regex_t
*pattern
= NULL
;
391 if (except_rx
!= NULL
)
393 pattern
= XNEW (regex_t
);
394 make_cleanup (xfree
, pattern
);
396 compile_rx_or_error (pattern
, except_rx
,
397 _("invalid type-matching regexp"));
400 cp
= XCNEW (struct exception_catchpoint
);
401 make_cleanup (xfree
, cp
);
403 init_catchpoint (&cp
->base
, get_current_arch (), tempflag
, cond_string
,
404 &gnu_v3_exception_catchpoint_ops
);
405 /* We need to reset 'type' in order for code in breakpoint.c to do
407 cp
->base
.type
= bp_breakpoint
;
409 cp
->exception_rx
= except_rx
;
410 cp
->pattern
= pattern
;
412 re_set_exception_catchpoint (&cp
->base
);
414 install_breakpoint (0, &cp
->base
, 1);
415 discard_cleanups (cleanup
);
418 /* Look for an "if" token in *STRING. The "if" token must be preceded
421 If there is any non-whitespace text between *STRING and the "if"
422 token, then it is returned in a newly-xmalloc'd string. Otherwise,
425 STRING is updated to point to the "if" token, if it exists, or to
426 the end of the string. */
429 extract_exception_regexp (char **string
)
432 char *last
, *last_space
;
434 start
= skip_spaces (*string
);
438 while (*last
!= '\0')
440 char *if_token
= last
;
442 /* Check for the "if". */
443 if (check_for_argument (&if_token
, "if", 2))
446 /* No "if" token here. Skip to the next word start. */
447 last_space
= skip_to_space (last
);
448 last
= skip_spaces (last_space
);
452 if (last_space
> start
)
453 return savestring (start
, last_space
- start
);
457 /* Deal with "catch catch", "catch throw", and "catch rethrow"
461 catch_exception_command_1 (enum exception_event_kind ex_event
, char *arg
,
462 int tempflag
, int from_tty
)
465 char *cond_string
= NULL
;
466 struct cleanup
*cleanup
;
470 arg
= skip_spaces (arg
);
472 except_rx
= extract_exception_regexp (&arg
);
473 cleanup
= make_cleanup (xfree
, except_rx
);
475 cond_string
= ep_parse_optional_if_clause (&arg
);
477 if ((*arg
!= '\0') && !isspace (*arg
))
478 error (_("Junk at end of arguments."));
480 if (ex_event
!= EX_EVENT_THROW
481 && ex_event
!= EX_EVENT_CATCH
482 && ex_event
!= EX_EVENT_RETHROW
)
483 error (_("Unsupported or unknown exception event; cannot catch it"));
485 handle_gnu_v3_exceptions (tempflag
, except_rx
, cond_string
,
488 discard_cleanups (cleanup
);
491 /* Implementation of "catch catch" command. */
494 catch_catch_command (char *arg
, int from_tty
, struct cmd_list_element
*command
)
496 int tempflag
= get_cmd_context (command
) == CATCH_TEMPORARY
;
498 catch_exception_command_1 (EX_EVENT_CATCH
, arg
, tempflag
, from_tty
);
501 /* Implementation of "catch throw" command. */
504 catch_throw_command (char *arg
, int from_tty
, struct cmd_list_element
*command
)
506 int tempflag
= get_cmd_context (command
) == CATCH_TEMPORARY
;
508 catch_exception_command_1 (EX_EVENT_THROW
, arg
, tempflag
, from_tty
);
511 /* Implementation of "catch rethrow" command. */
514 catch_rethrow_command (char *arg
, int from_tty
,
515 struct cmd_list_element
*command
)
517 int tempflag
= get_cmd_context (command
) == CATCH_TEMPORARY
;
519 catch_exception_command_1 (EX_EVENT_RETHROW
, arg
, tempflag
, from_tty
);
524 /* Implement the 'make_value' method for the $_exception
527 static struct value
*
528 compute_exception (struct gdbarch
*argc
, struct internalvar
*var
, void *ignore
)
530 struct value
*arg0
, *arg1
;
531 struct type
*obj_type
;
533 fetch_probe_arguments (&arg0
, &arg1
);
535 /* ARG0 is a pointer to the exception object. ARG1 is a pointer to
536 the std::type_info for the exception. Now we find the type from
537 the type_info and cast the result. */
538 obj_type
= cplus_type_from_type_info (arg1
);
539 return value_ind (value_cast (make_pointer_type (obj_type
, NULL
), arg0
));
542 /* Implementation of the '$_exception' variable. */
544 static const struct internalvar_funcs exception_funcs
=
554 initialize_throw_catchpoint_ops (void)
556 struct breakpoint_ops
*ops
;
558 initialize_breakpoint_ops ();
560 /* GNU v3 exception catchpoints. */
561 ops
= &gnu_v3_exception_catchpoint_ops
;
562 *ops
= bkpt_breakpoint_ops
;
563 ops
->dtor
= dtor_exception_catchpoint
;
564 ops
->re_set
= re_set_exception_catchpoint
;
565 ops
->print_it
= print_it_exception_catchpoint
;
566 ops
->print_one
= print_one_exception_catchpoint
;
567 ops
->print_mention
= print_mention_exception_catchpoint
;
568 ops
->print_recreate
= print_recreate_exception_catchpoint
;
569 ops
->print_one_detail
= print_one_detail_exception_catchpoint
;
570 ops
->check_status
= check_status_exception_catchpoint
;
573 initialize_file_ftype _initialize_break_catch_throw
;
576 _initialize_break_catch_throw (void)
578 initialize_throw_catchpoint_ops ();
580 /* Add catch and tcatch sub-commands. */
581 add_catch_command ("catch", _("\
582 Catch an exception, when caught."),
587 add_catch_command ("throw", _("\
588 Catch an exception, when thrown."),
593 add_catch_command ("rethrow", _("\
594 Catch an exception, when rethrown."),
595 catch_rethrow_command
,
600 create_internalvar_type_lazy ("_exception", &exception_funcs
, NULL
);