1 /* Everything about catch/throw catchpoints, for GDB.
3 Copyright (C) 1986-2017 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"
40 /* Enums for exception-handling support. */
41 enum exception_event_kind
48 /* Each spot where we may place an exception-related catchpoint has
49 two names: the SDT probe point and the function name. This
50 structure holds both. */
52 struct exception_names
54 /* The name of the probe point to try, in the form accepted by
59 /* The name of the corresponding function. */
64 /* Names of the probe points and functions on which to break. This is
65 indexed by exception_event_kind. */
66 static const struct exception_names exception_functions
[] =
68 { "-probe-stap libstdcxx:throw", "__cxa_throw" },
69 { "-probe-stap libstdcxx:rethrow", "__cxa_rethrow" },
70 { "-probe-stap libstdcxx:catch", "__cxa_begin_catch" }
73 static struct breakpoint_ops gnu_v3_exception_catchpoint_ops
;
75 /* The type of an exception catchpoint. */
77 struct exception_catchpoint
81 struct breakpoint base
;
83 /* The kind of exception catchpoint. */
85 enum exception_event_kind kind
;
87 /* If non-NULL, an xmalloc'd string holding the source form of the
88 regular expression to match against. */
92 /* If non-NULL, an xmalloc'd, compiled regular expression which is
93 used to determine which exceptions to stop on. */
100 /* A helper function that fetches exception probe arguments. This
101 fills in *ARG0 (if non-NULL) and *ARG1 (which must be non-NULL).
102 It will throw an exception on any kind of failure. */
105 fetch_probe_arguments (struct value
**arg0
, struct value
**arg1
)
107 struct frame_info
*frame
= get_selected_frame (_("No frame selected"));
108 CORE_ADDR pc
= get_frame_pc (frame
);
109 struct bound_probe pc_probe
;
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 std::string type_name
;
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
.c_str ());
184 std::swap (type_name
, canon
);
186 CATCH (e
, RETURN_MASK_ERROR
)
188 exception_print (gdb_stderr
, e
);
192 if (!type_name
.empty ())
194 if (regexec (self
->pattern
, type_name
.c_str (), 0, NULL
, 0) != 0)
199 /* Implement the 're_set' method. */
202 re_set_exception_catchpoint (struct breakpoint
*self
)
204 struct symtabs_and_lines sals
= {0};
205 struct symtabs_and_lines sals_end
= {0};
206 struct cleanup
*cleanup
;
207 enum exception_event_kind kind
= classify_exception_breakpoint (self
);
208 struct event_location
*location
;
209 struct program_space
*filter_pspace
= current_program_space
;
211 /* We first try to use the probe interface. */
215 = new_probe_location (exception_functions
[kind
].probe
);
216 cleanup
= make_cleanup_delete_event_location (location
);
217 sals
= parse_probes (location
, filter_pspace
, NULL
);
218 do_cleanups (cleanup
);
220 CATCH (e
, RETURN_MASK_ERROR
)
222 /* Using the probe interface failed. Let's fallback to the normal
226 struct explicit_location explicit_loc
;
228 initialize_explicit_location (&explicit_loc
);
229 explicit_loc
.function_name
230 = ASTRDUP (exception_functions
[kind
].function
);
231 location
= new_explicit_location (&explicit_loc
);
232 cleanup
= make_cleanup_delete_event_location (location
);
233 self
->ops
->decode_location (self
, location
, filter_pspace
, &sals
);
234 do_cleanups (cleanup
);
236 CATCH (ex
, RETURN_MASK_ERROR
)
238 /* NOT_FOUND_ERROR just means the breakpoint will be
239 pending, so let it through. */
240 if (ex
.error
!= NOT_FOUND_ERROR
)
241 throw_exception (ex
);
247 cleanup
= make_cleanup (xfree
, sals
.sals
);
248 update_breakpoint_locations (self
, filter_pspace
, sals
, sals_end
);
249 do_cleanups (cleanup
);
252 static enum print_stop_action
253 print_it_exception_catchpoint (bpstat bs
)
255 struct ui_out
*uiout
= current_uiout
;
256 struct breakpoint
*b
= bs
->breakpoint_at
;
258 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
260 annotate_catchpoint (b
->number
);
261 maybe_print_thread_hit_breakpoint (uiout
);
263 bp_temp
= b
->disposition
== disp_del
;
264 uiout
->text (bp_temp
? "Temporary catchpoint "
266 if (!uiout
->is_mi_like_p ())
267 uiout
->field_int ("bkptno", b
->number
);
268 uiout
->text ((kind
== EX_EVENT_THROW
? " (exception thrown), "
269 : (kind
== EX_EVENT_CATCH
? " (exception caught), "
270 : " (exception rethrown), ")));
271 if (uiout
->is_mi_like_p ())
273 uiout
->field_string ("reason",
274 async_reason_lookup (EXEC_ASYNC_BREAKPOINT_HIT
));
275 uiout
->field_string ("disp", bpdisp_text (b
->disposition
));
276 uiout
->field_int ("bkptno", b
->number
);
278 return PRINT_SRC_AND_LOC
;
282 print_one_exception_catchpoint (struct breakpoint
*b
,
283 struct bp_location
**last_loc
)
285 struct value_print_options opts
;
286 struct ui_out
*uiout
= current_uiout
;
287 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
289 get_user_print_options (&opts
);
290 if (opts
.addressprint
)
293 if (b
->loc
== NULL
|| b
->loc
->shlib_disabled
)
294 uiout
->field_string ("addr", "<PENDING>");
296 uiout
->field_core_addr ("addr",
297 b
->loc
->gdbarch
, b
->loc
->address
);
306 uiout
->field_string ("what", "exception throw");
307 if (uiout
->is_mi_like_p ())
308 uiout
->field_string ("catch-type", "throw");
311 case EX_EVENT_RETHROW
:
312 uiout
->field_string ("what", "exception rethrow");
313 if (uiout
->is_mi_like_p ())
314 uiout
->field_string ("catch-type", "rethrow");
318 uiout
->field_string ("what", "exception catch");
319 if (uiout
->is_mi_like_p ())
320 uiout
->field_string ("catch-type", "catch");
325 /* Implement the 'print_one_detail' method. */
328 print_one_detail_exception_catchpoint (const struct breakpoint
*b
,
329 struct ui_out
*uiout
)
331 const struct exception_catchpoint
*cp
332 = (const struct exception_catchpoint
*) b
;
334 if (cp
->exception_rx
!= NULL
)
336 uiout
->text (_("\tmatching: "));
337 uiout
->field_string ("regexp", cp
->exception_rx
);
343 print_mention_exception_catchpoint (struct breakpoint
*b
)
345 struct ui_out
*uiout
= current_uiout
;
347 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
349 bp_temp
= b
->disposition
== disp_del
;
350 uiout
->text (bp_temp
? _("Temporary catchpoint ")
352 uiout
->field_int ("bkptno", b
->number
);
353 uiout
->text ((kind
== EX_EVENT_THROW
? _(" (throw)")
354 : (kind
== EX_EVENT_CATCH
? _(" (catch)")
355 : _(" (rethrow)"))));
358 /* Implement the "print_recreate" breakpoint_ops method for throw and
359 catch catchpoints. */
362 print_recreate_exception_catchpoint (struct breakpoint
*b
,
366 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
368 bp_temp
= b
->disposition
== disp_del
;
369 fprintf_unfiltered (fp
, bp_temp
? "tcatch " : "catch ");
373 fprintf_unfiltered (fp
, "throw");
376 fprintf_unfiltered (fp
, "catch");
378 case EX_EVENT_RETHROW
:
379 fprintf_unfiltered (fp
, "rethrow");
382 print_recreate_thread (b
, fp
);
386 handle_gnu_v3_exceptions (int tempflag
, char *except_rx
, char *cond_string
,
387 enum exception_event_kind ex_event
, int from_tty
)
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 std::unique_ptr
<exception_catchpoint
> cp (new exception_catchpoint ());
402 init_catchpoint (&cp
->base
, get_current_arch (), tempflag
, cond_string
,
403 &gnu_v3_exception_catchpoint_ops
);
404 /* We need to reset 'type' in order for code in breakpoint.c to do
406 cp
->base
.type
= bp_breakpoint
;
408 cp
->exception_rx
= except_rx
;
409 cp
->pattern
= pattern
;
411 re_set_exception_catchpoint (&cp
->base
);
413 install_breakpoint (0, &cp
->base
, 1);
417 /* Look for an "if" token in *STRING. The "if" token must be preceded
420 If there is any non-whitespace text between *STRING and the "if"
421 token, then it is returned in a newly-xmalloc'd string. Otherwise,
424 STRING is updated to point to the "if" token, if it exists, or to
425 the end of the string. */
428 extract_exception_regexp (char **string
)
431 char *last
, *last_space
;
433 start
= skip_spaces (*string
);
437 while (*last
!= '\0')
439 char *if_token
= last
;
441 /* Check for the "if". */
442 if (check_for_argument (&if_token
, "if", 2))
445 /* No "if" token here. Skip to the next word start. */
446 last_space
= skip_to_space (last
);
447 last
= skip_spaces (last_space
);
451 if (last_space
> start
)
452 return savestring (start
, last_space
- start
);
456 /* Deal with "catch catch", "catch throw", and "catch rethrow"
460 catch_exception_command_1 (enum exception_event_kind ex_event
, char *arg
,
461 int tempflag
, int from_tty
)
464 char *cond_string
= NULL
;
465 struct cleanup
*cleanup
;
469 arg
= skip_spaces (arg
);
471 except_rx
= extract_exception_regexp (&arg
);
472 cleanup
= make_cleanup (xfree
, except_rx
);
474 cond_string
= ep_parse_optional_if_clause (&arg
);
476 if ((*arg
!= '\0') && !isspace (*arg
))
477 error (_("Junk at end of arguments."));
479 if (ex_event
!= EX_EVENT_THROW
480 && ex_event
!= EX_EVENT_CATCH
481 && ex_event
!= EX_EVENT_RETHROW
)
482 error (_("Unsupported or unknown exception event; cannot catch it"));
484 handle_gnu_v3_exceptions (tempflag
, except_rx
, cond_string
,
487 discard_cleanups (cleanup
);
490 /* Implementation of "catch catch" command. */
493 catch_catch_command (char *arg
, int from_tty
, struct cmd_list_element
*command
)
495 int tempflag
= get_cmd_context (command
) == CATCH_TEMPORARY
;
497 catch_exception_command_1 (EX_EVENT_CATCH
, arg
, tempflag
, from_tty
);
500 /* Implementation of "catch throw" command. */
503 catch_throw_command (char *arg
, int from_tty
, struct cmd_list_element
*command
)
505 int tempflag
= get_cmd_context (command
) == CATCH_TEMPORARY
;
507 catch_exception_command_1 (EX_EVENT_THROW
, arg
, tempflag
, from_tty
);
510 /* Implementation of "catch rethrow" command. */
513 catch_rethrow_command (char *arg
, int from_tty
,
514 struct cmd_list_element
*command
)
516 int tempflag
= get_cmd_context (command
) == CATCH_TEMPORARY
;
518 catch_exception_command_1 (EX_EVENT_RETHROW
, arg
, tempflag
, from_tty
);
523 /* Implement the 'make_value' method for the $_exception
526 static struct value
*
527 compute_exception (struct gdbarch
*argc
, struct internalvar
*var
, void *ignore
)
529 struct value
*arg0
, *arg1
;
530 struct type
*obj_type
;
532 fetch_probe_arguments (&arg0
, &arg1
);
534 /* ARG0 is a pointer to the exception object. ARG1 is a pointer to
535 the std::type_info for the exception. Now we find the type from
536 the type_info and cast the result. */
537 obj_type
= cplus_type_from_type_info (arg1
);
538 return value_ind (value_cast (make_pointer_type (obj_type
, NULL
), arg0
));
541 /* Implementation of the '$_exception' variable. */
543 static const struct internalvar_funcs exception_funcs
=
553 initialize_throw_catchpoint_ops (void)
555 struct breakpoint_ops
*ops
;
557 initialize_breakpoint_ops ();
559 /* GNU v3 exception catchpoints. */
560 ops
= &gnu_v3_exception_catchpoint_ops
;
561 *ops
= bkpt_breakpoint_ops
;
562 ops
->dtor
= dtor_exception_catchpoint
;
563 ops
->re_set
= re_set_exception_catchpoint
;
564 ops
->print_it
= print_it_exception_catchpoint
;
565 ops
->print_one
= print_one_exception_catchpoint
;
566 ops
->print_mention
= print_mention_exception_catchpoint
;
567 ops
->print_recreate
= print_recreate_exception_catchpoint
;
568 ops
->print_one_detail
= print_one_detail_exception_catchpoint
;
569 ops
->check_status
= check_status_exception_catchpoint
;
572 initialize_file_ftype _initialize_break_catch_throw
;
575 _initialize_break_catch_throw (void)
577 initialize_throw_catchpoint_ops ();
579 /* Add catch and tcatch sub-commands. */
580 add_catch_command ("catch", _("\
581 Catch an exception, when caught."),
586 add_catch_command ("throw", _("\
587 Catch an exception, when thrown."),
592 add_catch_command ("rethrow", _("\
593 Catch an exception, when rethrown."),
594 catch_rethrow_command
,
599 create_internalvar_type_lazy ("_exception", &exception_funcs
, NULL
);