1 /* Everything about catch/throw catchpoints, for GDB.
3 Copyright (C) 1986-2021 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 #include "cli/cli-decode.h"
41 /* Each spot where we may place an exception-related catchpoint has
42 two names: the SDT probe point and the function name. This
43 structure holds both. */
45 struct exception_names
47 /* The name of the probe point to try, in the form accepted by
52 /* The name of the corresponding function. */
57 /* Names of the probe points and functions on which to break. This is
58 indexed by exception_event_kind. */
59 static const struct exception_names exception_functions
[] =
61 { "-probe-stap libstdcxx:throw", "__cxa_throw" },
62 { "-probe-stap libstdcxx:rethrow", "__cxa_rethrow" },
63 { "-probe-stap libstdcxx:catch", "__cxa_begin_catch" }
66 static struct breakpoint_ops gnu_v3_exception_catchpoint_ops
;
68 /* The type of an exception catchpoint. */
70 struct exception_catchpoint
: public breakpoint
72 /* The kind of exception catchpoint. */
74 enum exception_event_kind kind
;
76 /* If not empty, a string holding the source form of the regular
77 expression to match against. */
79 std::string exception_rx
;
81 /* If non-NULL, a compiled regular expression which is used to
82 determine which exceptions to stop on. */
84 std::unique_ptr
<compiled_regex
> pattern
;
87 /* See breakpoint.h. */
90 is_exception_catchpoint (breakpoint
*bp
)
92 return bp
->ops
== &gnu_v3_exception_catchpoint_ops
;
97 /* A helper function that fetches exception probe arguments. This
98 fills in *ARG0 (if non-NULL) and *ARG1 (which must be non-NULL).
99 It will throw an exception on any kind of failure. */
102 fetch_probe_arguments (struct value
**arg0
, struct value
**arg1
)
104 struct frame_info
*frame
= get_selected_frame (_("No frame selected"));
105 CORE_ADDR pc
= get_frame_pc (frame
);
106 struct bound_probe pc_probe
;
109 pc_probe
= find_probe_by_pc (pc
);
110 if (pc_probe
.prob
== NULL
)
111 error (_("did not find exception probe (does libstdcxx have SDT probes?)"));
113 if (pc_probe
.prob
->get_provider () != "libstdcxx"
114 || (pc_probe
.prob
->get_name () != "catch"
115 && pc_probe
.prob
->get_name () != "throw"
116 && pc_probe
.prob
->get_name () != "rethrow"))
117 error (_("not stopped at a C++ exception catchpoint"));
119 n_args
= pc_probe
.prob
->get_argument_count (get_frame_arch (frame
));
121 error (_("C++ exception catchpoint has too few arguments"));
124 *arg0
= pc_probe
.prob
->evaluate_argument (0, frame
);
125 *arg1
= pc_probe
.prob
->evaluate_argument (1, frame
);
127 if ((arg0
!= NULL
&& *arg0
== NULL
) || *arg1
== NULL
)
128 error (_("error computing probe argument at c++ exception catchpoint"));
133 /* A helper function that returns a value indicating the kind of the
134 exception catchpoint B. */
136 static enum exception_event_kind
137 classify_exception_breakpoint (struct breakpoint
*b
)
139 struct exception_catchpoint
*cp
= (struct exception_catchpoint
*) b
;
144 /* Implement the 'check_status' method. */
147 check_status_exception_catchpoint (struct bpstat
*bs
)
149 struct exception_catchpoint
*self
150 = (struct exception_catchpoint
*) bs
->breakpoint_at
;
151 std::string type_name
;
153 bkpt_breakpoint_ops
.check_status (bs
);
157 if (self
->pattern
== NULL
)
160 const char *name
= nullptr;
161 gdb::unique_xmalloc_ptr
<char> canon
;
164 struct value
*typeinfo_arg
;
166 fetch_probe_arguments (NULL
, &typeinfo_arg
);
167 type_name
= cplus_typename_from_type_info (typeinfo_arg
);
169 canon
= cp_canonicalize_string (type_name
.c_str ());
170 name
= (canon
!= nullptr
172 : type_name
.c_str ());
174 catch (const gdb_exception_error
&e
)
176 exception_print (gdb_stderr
, e
);
181 if (self
->pattern
->exec (name
, 0, NULL
, 0) != 0)
186 /* Implement the 're_set' method. */
189 re_set_exception_catchpoint (struct breakpoint
*self
)
191 std::vector
<symtab_and_line
> sals
;
192 enum exception_event_kind kind
= classify_exception_breakpoint (self
);
193 struct program_space
*filter_pspace
= current_program_space
;
195 /* We first try to use the probe interface. */
198 event_location_up location
199 = new_probe_location (exception_functions
[kind
].probe
);
200 sals
= parse_probes (location
.get (), filter_pspace
, NULL
);
202 catch (const gdb_exception_error
&e
)
204 /* Using the probe interface failed. Let's fallback to the normal
208 struct explicit_location explicit_loc
;
210 initialize_explicit_location (&explicit_loc
);
211 explicit_loc
.function_name
212 = ASTRDUP (exception_functions
[kind
].function
);
213 event_location_up location
= new_explicit_location (&explicit_loc
);
214 sals
= self
->ops
->decode_location (self
, location
.get (),
217 catch (const gdb_exception_error
&ex
)
219 /* NOT_FOUND_ERROR just means the breakpoint will be
220 pending, so let it through. */
221 if (ex
.error
!= NOT_FOUND_ERROR
)
226 update_breakpoint_locations (self
, filter_pspace
, sals
, {});
229 static enum print_stop_action
230 print_it_exception_catchpoint (bpstat
*bs
)
232 struct ui_out
*uiout
= current_uiout
;
233 struct breakpoint
*b
= bs
->breakpoint_at
;
235 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
237 annotate_catchpoint (b
->number
);
238 maybe_print_thread_hit_breakpoint (uiout
);
240 bp_temp
= b
->disposition
== disp_del
;
241 uiout
->text (bp_temp
? "Temporary catchpoint "
243 uiout
->field_signed ("bkptno", b
->number
);
244 uiout
->text ((kind
== EX_EVENT_THROW
? " (exception thrown), "
245 : (kind
== EX_EVENT_CATCH
? " (exception caught), "
246 : " (exception rethrown), ")));
247 if (uiout
->is_mi_like_p ())
249 uiout
->field_string ("reason",
250 async_reason_lookup (EXEC_ASYNC_BREAKPOINT_HIT
));
251 uiout
->field_string ("disp", bpdisp_text (b
->disposition
));
253 return PRINT_SRC_AND_LOC
;
257 print_one_exception_catchpoint (struct breakpoint
*b
,
258 struct bp_location
**last_loc
)
260 struct value_print_options opts
;
261 struct ui_out
*uiout
= current_uiout
;
262 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
264 get_user_print_options (&opts
);
266 if (opts
.addressprint
)
267 uiout
->field_skip ("addr");
273 uiout
->field_string ("what", "exception throw");
274 if (uiout
->is_mi_like_p ())
275 uiout
->field_string ("catch-type", "throw");
278 case EX_EVENT_RETHROW
:
279 uiout
->field_string ("what", "exception rethrow");
280 if (uiout
->is_mi_like_p ())
281 uiout
->field_string ("catch-type", "rethrow");
285 uiout
->field_string ("what", "exception catch");
286 if (uiout
->is_mi_like_p ())
287 uiout
->field_string ("catch-type", "catch");
292 /* Implement the 'print_one_detail' method. */
295 print_one_detail_exception_catchpoint (const struct breakpoint
*b
,
296 struct ui_out
*uiout
)
298 const struct exception_catchpoint
*cp
299 = (const struct exception_catchpoint
*) b
;
301 if (!cp
->exception_rx
.empty ())
303 uiout
->text (_("\tmatching: "));
304 uiout
->field_string ("regexp", cp
->exception_rx
);
310 print_mention_exception_catchpoint (struct breakpoint
*b
)
312 struct ui_out
*uiout
= current_uiout
;
314 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
316 bp_temp
= b
->disposition
== disp_del
;
317 uiout
->message ("%s %d %s",
318 (bp_temp
? _("Temporary catchpoint ") : _("Catchpoint")),
320 (kind
== EX_EVENT_THROW
321 ? _("(throw)") : (kind
== EX_EVENT_CATCH
322 ? _("(catch)") : _("(rethrow)"))));
325 /* Implement the "print_recreate" breakpoint_ops method for throw and
326 catch catchpoints. */
329 print_recreate_exception_catchpoint (struct breakpoint
*b
,
333 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
335 bp_temp
= b
->disposition
== disp_del
;
336 fprintf_unfiltered (fp
, bp_temp
? "tcatch " : "catch ");
340 fprintf_unfiltered (fp
, "throw");
343 fprintf_unfiltered (fp
, "catch");
345 case EX_EVENT_RETHROW
:
346 fprintf_unfiltered (fp
, "rethrow");
349 print_recreate_thread (b
, fp
);
352 /* Implement the "allocate_location" breakpoint_ops method for throw
353 and catch catchpoints. */
356 allocate_location_exception_catchpoint (breakpoint
*self
)
358 return new bp_location (self
, bp_loc_software_breakpoint
);
362 handle_gnu_v3_exceptions (int tempflag
, std::string
&&except_rx
,
363 const char *cond_string
,
364 enum exception_event_kind ex_event
, int from_tty
)
366 std::unique_ptr
<compiled_regex
> pattern
;
368 if (!except_rx
.empty ())
370 pattern
.reset (new compiled_regex (except_rx
.c_str (), REG_NOSUB
,
371 _("invalid type-matching regexp")));
374 std::unique_ptr
<exception_catchpoint
> cp (new exception_catchpoint ());
376 init_catchpoint (cp
.get (), get_current_arch (), tempflag
, cond_string
,
377 &gnu_v3_exception_catchpoint_ops
);
379 cp
->exception_rx
= std::move (except_rx
);
380 cp
->pattern
= std::move (pattern
);
382 re_set_exception_catchpoint (cp
.get ());
384 install_breakpoint (0, std::move (cp
), 1);
387 /* Look for an "if" token in *STRING. The "if" token must be preceded
390 If there is any non-whitespace text between *STRING and the "if"
391 token, then it is returned in a newly-xmalloc'd string. Otherwise,
394 STRING is updated to point to the "if" token, if it exists, or to
395 the end of the string. */
398 extract_exception_regexp (const char **string
)
401 const char *last
, *last_space
;
403 start
= skip_spaces (*string
);
407 while (*last
!= '\0')
409 const char *if_token
= last
;
411 /* Check for the "if". */
412 if (check_for_argument (&if_token
, "if", 2))
415 /* No "if" token here. Skip to the next word start. */
416 last_space
= skip_to_space (last
);
417 last
= skip_spaces (last_space
);
421 if (last_space
> start
)
422 return std::string (start
, last_space
- start
);
423 return std::string ();
426 /* See breakpoint.h. */
429 catch_exception_event (enum exception_event_kind ex_event
,
430 const char *arg
, bool tempflag
, int from_tty
)
432 const char *cond_string
= NULL
;
436 arg
= skip_spaces (arg
);
438 std::string except_rx
= extract_exception_regexp (&arg
);
440 cond_string
= ep_parse_optional_if_clause (&arg
);
442 if ((*arg
!= '\0') && !isspace (*arg
))
443 error (_("Junk at end of arguments."));
445 if (ex_event
!= EX_EVENT_THROW
446 && ex_event
!= EX_EVENT_CATCH
447 && ex_event
!= EX_EVENT_RETHROW
)
448 error (_("Unsupported or unknown exception event; cannot catch it"));
450 handle_gnu_v3_exceptions (tempflag
, std::move (except_rx
), cond_string
,
454 /* Implementation of "catch catch" command. */
457 catch_catch_command (const char *arg
, int from_tty
,
458 struct cmd_list_element
*command
)
460 bool tempflag
= command
->context () == CATCH_TEMPORARY
;
462 catch_exception_event (EX_EVENT_CATCH
, arg
, tempflag
, from_tty
);
465 /* Implementation of "catch throw" command. */
468 catch_throw_command (const char *arg
, int from_tty
,
469 struct cmd_list_element
*command
)
471 bool tempflag
= command
->context () == CATCH_TEMPORARY
;
473 catch_exception_event (EX_EVENT_THROW
, arg
, tempflag
, from_tty
);
476 /* Implementation of "catch rethrow" command. */
479 catch_rethrow_command (const char *arg
, int from_tty
,
480 struct cmd_list_element
*command
)
482 bool tempflag
= command
->context () == CATCH_TEMPORARY
;
484 catch_exception_event (EX_EVENT_RETHROW
, arg
, tempflag
, from_tty
);
489 /* Implement the 'make_value' method for the $_exception
492 static struct value
*
493 compute_exception (struct gdbarch
*argc
, struct internalvar
*var
, void *ignore
)
495 struct value
*arg0
, *arg1
;
496 struct type
*obj_type
;
498 fetch_probe_arguments (&arg0
, &arg1
);
500 /* ARG0 is a pointer to the exception object. ARG1 is a pointer to
501 the std::type_info for the exception. Now we find the type from
502 the type_info and cast the result. */
503 obj_type
= cplus_type_from_type_info (arg1
);
504 return value_ind (value_cast (make_pointer_type (obj_type
, NULL
), arg0
));
507 /* Implementation of the '$_exception' variable. */
509 static const struct internalvar_funcs exception_funcs
=
519 initialize_throw_catchpoint_ops (void)
521 struct breakpoint_ops
*ops
;
523 initialize_breakpoint_ops ();
525 /* GNU v3 exception catchpoints. */
526 ops
= &gnu_v3_exception_catchpoint_ops
;
527 *ops
= bkpt_breakpoint_ops
;
528 ops
->re_set
= re_set_exception_catchpoint
;
529 ops
->print_it
= print_it_exception_catchpoint
;
530 ops
->print_one
= print_one_exception_catchpoint
;
531 ops
->print_mention
= print_mention_exception_catchpoint
;
532 ops
->print_recreate
= print_recreate_exception_catchpoint
;
533 ops
->print_one_detail
= print_one_detail_exception_catchpoint
;
534 ops
->check_status
= check_status_exception_catchpoint
;
535 ops
->allocate_location
= allocate_location_exception_catchpoint
;
538 void _initialize_break_catch_throw ();
540 _initialize_break_catch_throw ()
542 initialize_throw_catchpoint_ops ();
544 /* Add catch and tcatch sub-commands. */
545 add_catch_command ("catch", _("\
546 Catch an exception, when caught."),
551 add_catch_command ("throw", _("\
552 Catch an exception, when thrown."),
557 add_catch_command ("rethrow", _("\
558 Catch an exception, when rethrown."),
559 catch_rethrow_command
,
564 create_internalvar_type_lazy ("_exception", &exception_funcs
, NULL
);