1 /* Everything about catch/throw catchpoints, for GDB.
3 Copyright (C) 1986-2019 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 /* Each spot where we may place an exception-related catchpoint has
41 two names: the SDT probe point and the function name. This
42 structure holds both. */
44 struct exception_names
46 /* The name of the probe point to try, in the form accepted by
51 /* The name of the corresponding function. */
56 /* Names of the probe points and functions on which to break. This is
57 indexed by exception_event_kind. */
58 static const struct exception_names exception_functions
[] =
60 { "-probe-stap libstdcxx:throw", "__cxa_throw" },
61 { "-probe-stap libstdcxx:rethrow", "__cxa_rethrow" },
62 { "-probe-stap libstdcxx:catch", "__cxa_begin_catch" }
65 static struct breakpoint_ops gnu_v3_exception_catchpoint_ops
;
67 /* The type of an exception catchpoint. */
69 struct exception_catchpoint
: public breakpoint
71 /* The kind of exception catchpoint. */
73 enum exception_event_kind kind
;
75 /* If not empty, a string holding the source form of the regular
76 expression to match against. */
78 std::string exception_rx
;
80 /* If non-NULL, a compiled regular expression which is used to
81 determine which exceptions to stop on. */
83 std::unique_ptr
<compiled_regex
> pattern
;
88 /* A helper function that fetches exception probe arguments. This
89 fills in *ARG0 (if non-NULL) and *ARG1 (which must be non-NULL).
90 It will throw an exception on any kind of failure. */
93 fetch_probe_arguments (struct value
**arg0
, struct value
**arg1
)
95 struct frame_info
*frame
= get_selected_frame (_("No frame selected"));
96 CORE_ADDR pc
= get_frame_pc (frame
);
97 struct bound_probe pc_probe
;
100 pc_probe
= find_probe_by_pc (pc
);
101 if (pc_probe
.prob
== NULL
102 || pc_probe
.prob
->get_provider () != "libstdcxx"
103 || (pc_probe
.prob
->get_name () != "catch"
104 && pc_probe
.prob
->get_name () != "throw"
105 && pc_probe
.prob
->get_name () != "rethrow"))
106 error (_("not stopped at a C++ exception catchpoint"));
108 n_args
= pc_probe
.prob
->get_argument_count (frame
);
110 error (_("C++ exception catchpoint has too few arguments"));
113 *arg0
= pc_probe
.prob
->evaluate_argument (0, frame
);
114 *arg1
= pc_probe
.prob
->evaluate_argument (1, frame
);
116 if ((arg0
!= NULL
&& *arg0
== NULL
) || *arg1
== NULL
)
117 error (_("error computing probe argument at c++ exception catchpoint"));
122 /* A helper function that returns a value indicating the kind of the
123 exception catchpoint B. */
125 static enum exception_event_kind
126 classify_exception_breakpoint (struct breakpoint
*b
)
128 struct exception_catchpoint
*cp
= (struct exception_catchpoint
*) b
;
133 /* Implement the 'check_status' method. */
136 check_status_exception_catchpoint (struct bpstats
*bs
)
138 struct exception_catchpoint
*self
139 = (struct exception_catchpoint
*) bs
->breakpoint_at
;
140 std::string type_name
;
142 bkpt_breakpoint_ops
.check_status (bs
);
146 if (self
->pattern
== NULL
)
151 struct value
*typeinfo_arg
;
154 fetch_probe_arguments (NULL
, &typeinfo_arg
);
155 type_name
= cplus_typename_from_type_info (typeinfo_arg
);
157 canon
= cp_canonicalize_string (type_name
.c_str ());
159 std::swap (type_name
, canon
);
161 catch (const gdb_exception_error
&e
)
163 exception_print (gdb_stderr
, e
);
166 if (!type_name
.empty ())
168 if (self
->pattern
->exec (type_name
.c_str (), 0, NULL
, 0) != 0)
173 /* Implement the 're_set' method. */
176 re_set_exception_catchpoint (struct breakpoint
*self
)
178 std::vector
<symtab_and_line
> sals
;
179 enum exception_event_kind kind
= classify_exception_breakpoint (self
);
180 struct program_space
*filter_pspace
= current_program_space
;
182 /* We first try to use the probe interface. */
185 event_location_up location
186 = new_probe_location (exception_functions
[kind
].probe
);
187 sals
= parse_probes (location
.get (), filter_pspace
, NULL
);
189 catch (const gdb_exception_error
&e
)
191 /* Using the probe interface failed. Let's fallback to the normal
195 struct explicit_location explicit_loc
;
197 initialize_explicit_location (&explicit_loc
);
198 explicit_loc
.function_name
199 = ASTRDUP (exception_functions
[kind
].function
);
200 event_location_up location
= new_explicit_location (&explicit_loc
);
201 sals
= self
->ops
->decode_location (self
, location
.get (),
204 catch (const gdb_exception_error
&ex
)
206 /* NOT_FOUND_ERROR just means the breakpoint will be
207 pending, so let it through. */
208 if (ex
.error
!= NOT_FOUND_ERROR
)
213 update_breakpoint_locations (self
, filter_pspace
, sals
, {});
216 static enum print_stop_action
217 print_it_exception_catchpoint (bpstat bs
)
219 struct ui_out
*uiout
= current_uiout
;
220 struct breakpoint
*b
= bs
->breakpoint_at
;
222 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
224 annotate_catchpoint (b
->number
);
225 maybe_print_thread_hit_breakpoint (uiout
);
227 bp_temp
= b
->disposition
== disp_del
;
228 uiout
->text (bp_temp
? "Temporary catchpoint "
230 uiout
->field_int ("bkptno", b
->number
);
231 uiout
->text ((kind
== EX_EVENT_THROW
? " (exception thrown), "
232 : (kind
== EX_EVENT_CATCH
? " (exception caught), "
233 : " (exception rethrown), ")));
234 if (uiout
->is_mi_like_p ())
236 uiout
->field_string ("reason",
237 async_reason_lookup (EXEC_ASYNC_BREAKPOINT_HIT
));
238 uiout
->field_string ("disp", bpdisp_text (b
->disposition
));
240 return PRINT_SRC_AND_LOC
;
244 print_one_exception_catchpoint (struct breakpoint
*b
,
245 struct bp_location
**last_loc
)
247 struct value_print_options opts
;
248 struct ui_out
*uiout
= current_uiout
;
249 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
251 get_user_print_options (&opts
);
252 if (opts
.addressprint
)
255 if (b
->loc
== NULL
|| b
->loc
->shlib_disabled
)
256 uiout
->field_string ("addr", "<PENDING>");
258 uiout
->field_core_addr ("addr",
259 b
->loc
->gdbarch
, b
->loc
->address
);
268 uiout
->field_string ("what", "exception throw");
269 if (uiout
->is_mi_like_p ())
270 uiout
->field_string ("catch-type", "throw");
273 case EX_EVENT_RETHROW
:
274 uiout
->field_string ("what", "exception rethrow");
275 if (uiout
->is_mi_like_p ())
276 uiout
->field_string ("catch-type", "rethrow");
280 uiout
->field_string ("what", "exception catch");
281 if (uiout
->is_mi_like_p ())
282 uiout
->field_string ("catch-type", "catch");
287 /* Implement the 'print_one_detail' method. */
290 print_one_detail_exception_catchpoint (const struct breakpoint
*b
,
291 struct ui_out
*uiout
)
293 const struct exception_catchpoint
*cp
294 = (const struct exception_catchpoint
*) b
;
296 if (!cp
->exception_rx
.empty ())
298 uiout
->text (_("\tmatching: "));
299 uiout
->field_string ("regexp", cp
->exception_rx
.c_str ());
305 print_mention_exception_catchpoint (struct breakpoint
*b
)
307 struct ui_out
*uiout
= current_uiout
;
309 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
311 bp_temp
= b
->disposition
== disp_del
;
312 uiout
->message ("%s %d %s",
313 (bp_temp
? _("Temporary catchpoint ") : _("Catchpoint")),
315 (kind
== EX_EVENT_THROW
316 ? _("(throw)") : (kind
== EX_EVENT_CATCH
317 ? _("(catch)") : _("(rethrow)"))));
320 /* Implement the "print_recreate" breakpoint_ops method for throw and
321 catch catchpoints. */
324 print_recreate_exception_catchpoint (struct breakpoint
*b
,
328 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
330 bp_temp
= b
->disposition
== disp_del
;
331 fprintf_unfiltered (fp
, bp_temp
? "tcatch " : "catch ");
335 fprintf_unfiltered (fp
, "throw");
338 fprintf_unfiltered (fp
, "catch");
340 case EX_EVENT_RETHROW
:
341 fprintf_unfiltered (fp
, "rethrow");
344 print_recreate_thread (b
, fp
);
348 handle_gnu_v3_exceptions (int tempflag
, std::string
&&except_rx
,
349 const char *cond_string
,
350 enum exception_event_kind ex_event
, int from_tty
)
352 std::unique_ptr
<compiled_regex
> pattern
;
354 if (!except_rx
.empty ())
356 pattern
.reset (new compiled_regex (except_rx
.c_str (), REG_NOSUB
,
357 _("invalid type-matching regexp")));
360 std::unique_ptr
<exception_catchpoint
> cp (new exception_catchpoint ());
362 init_catchpoint (cp
.get (), get_current_arch (), tempflag
, cond_string
,
363 &gnu_v3_exception_catchpoint_ops
);
364 /* We need to reset 'type' in order for code in breakpoint.c to do
366 cp
->type
= bp_breakpoint
;
368 cp
->exception_rx
= std::move (except_rx
);
369 cp
->pattern
= std::move (pattern
);
371 re_set_exception_catchpoint (cp
.get ());
373 install_breakpoint (0, std::move (cp
), 1);
376 /* Look for an "if" token in *STRING. The "if" token must be preceded
379 If there is any non-whitespace text between *STRING and the "if"
380 token, then it is returned in a newly-xmalloc'd string. Otherwise,
383 STRING is updated to point to the "if" token, if it exists, or to
384 the end of the string. */
387 extract_exception_regexp (const char **string
)
390 const char *last
, *last_space
;
392 start
= skip_spaces (*string
);
396 while (*last
!= '\0')
398 const char *if_token
= last
;
400 /* Check for the "if". */
401 if (check_for_argument (&if_token
, "if", 2))
404 /* No "if" token here. Skip to the next word start. */
405 last_space
= skip_to_space (last
);
406 last
= skip_spaces (last_space
);
410 if (last_space
> start
)
411 return std::string (start
, last_space
- start
);
412 return std::string ();
415 /* See breakpoint.h. */
418 catch_exception_event (enum exception_event_kind ex_event
,
419 const char *arg
, bool tempflag
, int from_tty
)
421 const char *cond_string
= NULL
;
425 arg
= skip_spaces (arg
);
427 std::string except_rx
= extract_exception_regexp (&arg
);
429 cond_string
= ep_parse_optional_if_clause (&arg
);
431 if ((*arg
!= '\0') && !isspace (*arg
))
432 error (_("Junk at end of arguments."));
434 if (ex_event
!= EX_EVENT_THROW
435 && ex_event
!= EX_EVENT_CATCH
436 && ex_event
!= EX_EVENT_RETHROW
)
437 error (_("Unsupported or unknown exception event; cannot catch it"));
439 handle_gnu_v3_exceptions (tempflag
, std::move (except_rx
), cond_string
,
443 /* Implementation of "catch catch" command. */
446 catch_catch_command (const char *arg
, int from_tty
,
447 struct cmd_list_element
*command
)
449 bool tempflag
= get_cmd_context (command
) == CATCH_TEMPORARY
;
451 catch_exception_event (EX_EVENT_CATCH
, arg
, tempflag
, from_tty
);
454 /* Implementation of "catch throw" command. */
457 catch_throw_command (const char *arg
, int from_tty
,
458 struct cmd_list_element
*command
)
460 bool tempflag
= get_cmd_context (command
) == CATCH_TEMPORARY
;
462 catch_exception_event (EX_EVENT_THROW
, arg
, tempflag
, from_tty
);
465 /* Implementation of "catch rethrow" command. */
468 catch_rethrow_command (const char *arg
, int from_tty
,
469 struct cmd_list_element
*command
)
471 bool tempflag
= get_cmd_context (command
) == CATCH_TEMPORARY
;
473 catch_exception_event (EX_EVENT_RETHROW
, arg
, tempflag
, from_tty
);
478 /* Implement the 'make_value' method for the $_exception
481 static struct value
*
482 compute_exception (struct gdbarch
*argc
, struct internalvar
*var
, void *ignore
)
484 struct value
*arg0
, *arg1
;
485 struct type
*obj_type
;
487 fetch_probe_arguments (&arg0
, &arg1
);
489 /* ARG0 is a pointer to the exception object. ARG1 is a pointer to
490 the std::type_info for the exception. Now we find the type from
491 the type_info and cast the result. */
492 obj_type
= cplus_type_from_type_info (arg1
);
493 return value_ind (value_cast (make_pointer_type (obj_type
, NULL
), arg0
));
496 /* Implementation of the '$_exception' variable. */
498 static const struct internalvar_funcs exception_funcs
=
508 initialize_throw_catchpoint_ops (void)
510 struct breakpoint_ops
*ops
;
512 initialize_breakpoint_ops ();
514 /* GNU v3 exception catchpoints. */
515 ops
= &gnu_v3_exception_catchpoint_ops
;
516 *ops
= bkpt_breakpoint_ops
;
517 ops
->re_set
= re_set_exception_catchpoint
;
518 ops
->print_it
= print_it_exception_catchpoint
;
519 ops
->print_one
= print_one_exception_catchpoint
;
520 ops
->print_mention
= print_mention_exception_catchpoint
;
521 ops
->print_recreate
= print_recreate_exception_catchpoint
;
522 ops
->print_one_detail
= print_one_detail_exception_catchpoint
;
523 ops
->check_status
= check_status_exception_catchpoint
;
527 _initialize_break_catch_throw (void)
529 initialize_throw_catchpoint_ops ();
531 /* Add catch and tcatch sub-commands. */
532 add_catch_command ("catch", _("\
533 Catch an exception, when caught."),
538 add_catch_command ("throw", _("\
539 Catch an exception, when thrown."),
544 add_catch_command ("rethrow", _("\
545 Catch an exception, when rethrown."),
546 catch_rethrow_command
,
551 create_internalvar_type_lazy ("_exception", &exception_funcs
, NULL
);