1 /* Everything about catch/throw catchpoints, for GDB.
3 Copyright (C) 1986-2018 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
: public breakpoint
79 /* The kind of exception catchpoint. */
81 enum exception_event_kind kind
;
83 /* If not empty, a string holding the source form of the regular
84 expression to match against. */
86 std::string exception_rx
;
88 /* If non-NULL, a compiled regular expression which is used to
89 determine which exceptions to stop on. */
91 std::unique_ptr
<compiled_regex
> pattern
;
96 /* A helper function that fetches exception probe arguments. This
97 fills in *ARG0 (if non-NULL) and *ARG1 (which must be non-NULL).
98 It will throw an exception on any kind of failure. */
101 fetch_probe_arguments (struct value
**arg0
, struct value
**arg1
)
103 struct frame_info
*frame
= get_selected_frame (_("No frame selected"));
104 CORE_ADDR pc
= get_frame_pc (frame
);
105 struct bound_probe pc_probe
;
108 pc_probe
= find_probe_by_pc (pc
);
109 if (pc_probe
.prob
== NULL
110 || pc_probe
.prob
->get_provider () != "libstdcxx"
111 || (pc_probe
.prob
->get_name () != "catch"
112 && pc_probe
.prob
->get_name () != "throw"
113 && pc_probe
.prob
->get_name () != "rethrow"))
114 error (_("not stopped at a C++ exception catchpoint"));
116 n_args
= pc_probe
.prob
->get_argument_count (frame
);
118 error (_("C++ exception catchpoint has too few arguments"));
121 *arg0
= pc_probe
.prob
->evaluate_argument (0, frame
);
122 *arg1
= pc_probe
.prob
->evaluate_argument (1, frame
);
124 if ((arg0
!= NULL
&& *arg0
== NULL
) || *arg1
== NULL
)
125 error (_("error computing probe argument at c++ exception catchpoint"));
130 /* A helper function that returns a value indicating the kind of the
131 exception catchpoint B. */
133 static enum exception_event_kind
134 classify_exception_breakpoint (struct breakpoint
*b
)
136 struct exception_catchpoint
*cp
= (struct exception_catchpoint
*) b
;
141 /* Implement the 'check_status' method. */
144 check_status_exception_catchpoint (struct bpstats
*bs
)
146 struct exception_catchpoint
*self
147 = (struct exception_catchpoint
*) bs
->breakpoint_at
;
148 std::string type_name
;
150 bkpt_breakpoint_ops
.check_status (bs
);
154 if (self
->pattern
== NULL
)
159 struct value
*typeinfo_arg
;
162 fetch_probe_arguments (NULL
, &typeinfo_arg
);
163 type_name
= cplus_typename_from_type_info (typeinfo_arg
);
165 canon
= cp_canonicalize_string (type_name
.c_str ());
167 std::swap (type_name
, canon
);
169 CATCH (e
, RETURN_MASK_ERROR
)
171 exception_print (gdb_stderr
, e
);
175 if (!type_name
.empty ())
177 if (self
->pattern
->exec (type_name
.c_str (), 0, NULL
, 0) != 0)
182 /* Implement the 're_set' method. */
185 re_set_exception_catchpoint (struct breakpoint
*self
)
187 std::vector
<symtab_and_line
> sals
;
188 enum exception_event_kind kind
= classify_exception_breakpoint (self
);
189 struct program_space
*filter_pspace
= current_program_space
;
191 /* We first try to use the probe interface. */
194 event_location_up location
195 = new_probe_location (exception_functions
[kind
].probe
);
196 sals
= parse_probes (location
.get (), filter_pspace
, NULL
);
198 CATCH (e
, RETURN_MASK_ERROR
)
200 /* Using the probe interface failed. Let's fallback to the normal
204 struct explicit_location explicit_loc
;
206 initialize_explicit_location (&explicit_loc
);
207 explicit_loc
.function_name
208 = ASTRDUP (exception_functions
[kind
].function
);
209 event_location_up location
= new_explicit_location (&explicit_loc
);
210 sals
= self
->ops
->decode_location (self
, location
.get (),
213 CATCH (ex
, RETURN_MASK_ERROR
)
215 /* NOT_FOUND_ERROR just means the breakpoint will be
216 pending, so let it through. */
217 if (ex
.error
!= NOT_FOUND_ERROR
)
218 throw_exception (ex
);
224 update_breakpoint_locations (self
, filter_pspace
, sals
, {});
227 static enum print_stop_action
228 print_it_exception_catchpoint (bpstat bs
)
230 struct ui_out
*uiout
= current_uiout
;
231 struct breakpoint
*b
= bs
->breakpoint_at
;
233 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
235 annotate_catchpoint (b
->number
);
236 maybe_print_thread_hit_breakpoint (uiout
);
238 bp_temp
= b
->disposition
== disp_del
;
239 uiout
->text (bp_temp
? "Temporary catchpoint "
241 uiout
->field_int ("bkptno", b
->number
);
242 uiout
->text ((kind
== EX_EVENT_THROW
? " (exception thrown), "
243 : (kind
== EX_EVENT_CATCH
? " (exception caught), "
244 : " (exception rethrown), ")));
245 if (uiout
->is_mi_like_p ())
247 uiout
->field_string ("reason",
248 async_reason_lookup (EXEC_ASYNC_BREAKPOINT_HIT
));
249 uiout
->field_string ("disp", bpdisp_text (b
->disposition
));
251 return PRINT_SRC_AND_LOC
;
255 print_one_exception_catchpoint (struct breakpoint
*b
,
256 struct bp_location
**last_loc
)
258 struct value_print_options opts
;
259 struct ui_out
*uiout
= current_uiout
;
260 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
262 get_user_print_options (&opts
);
263 if (opts
.addressprint
)
266 if (b
->loc
== NULL
|| b
->loc
->shlib_disabled
)
267 uiout
->field_string ("addr", "<PENDING>");
269 uiout
->field_core_addr ("addr",
270 b
->loc
->gdbarch
, b
->loc
->address
);
279 uiout
->field_string ("what", "exception throw");
280 if (uiout
->is_mi_like_p ())
281 uiout
->field_string ("catch-type", "throw");
284 case EX_EVENT_RETHROW
:
285 uiout
->field_string ("what", "exception rethrow");
286 if (uiout
->is_mi_like_p ())
287 uiout
->field_string ("catch-type", "rethrow");
291 uiout
->field_string ("what", "exception catch");
292 if (uiout
->is_mi_like_p ())
293 uiout
->field_string ("catch-type", "catch");
298 /* Implement the 'print_one_detail' method. */
301 print_one_detail_exception_catchpoint (const struct breakpoint
*b
,
302 struct ui_out
*uiout
)
304 const struct exception_catchpoint
*cp
305 = (const struct exception_catchpoint
*) b
;
307 if (!cp
->exception_rx
.empty ())
309 uiout
->text (_("\tmatching: "));
310 uiout
->field_string ("regexp", cp
->exception_rx
.c_str ());
316 print_mention_exception_catchpoint (struct breakpoint
*b
)
318 struct ui_out
*uiout
= current_uiout
;
320 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
322 bp_temp
= b
->disposition
== disp_del
;
323 uiout
->text (bp_temp
? _("Temporary catchpoint ")
325 uiout
->field_int ("bkptno", b
->number
);
326 uiout
->text ((kind
== EX_EVENT_THROW
? _(" (throw)")
327 : (kind
== EX_EVENT_CATCH
? _(" (catch)")
328 : _(" (rethrow)"))));
331 /* Implement the "print_recreate" breakpoint_ops method for throw and
332 catch catchpoints. */
335 print_recreate_exception_catchpoint (struct breakpoint
*b
,
339 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
341 bp_temp
= b
->disposition
== disp_del
;
342 fprintf_unfiltered (fp
, bp_temp
? "tcatch " : "catch ");
346 fprintf_unfiltered (fp
, "throw");
349 fprintf_unfiltered (fp
, "catch");
351 case EX_EVENT_RETHROW
:
352 fprintf_unfiltered (fp
, "rethrow");
355 print_recreate_thread (b
, fp
);
359 handle_gnu_v3_exceptions (int tempflag
, std::string
&&except_rx
,
360 const char *cond_string
,
361 enum exception_event_kind ex_event
, int from_tty
)
363 std::unique_ptr
<compiled_regex
> pattern
;
365 if (!except_rx
.empty ())
367 pattern
.reset (new compiled_regex (except_rx
.c_str (), REG_NOSUB
,
368 _("invalid type-matching regexp")));
371 std::unique_ptr
<exception_catchpoint
> cp (new exception_catchpoint ());
373 init_catchpoint (cp
.get (), get_current_arch (), tempflag
, cond_string
,
374 &gnu_v3_exception_catchpoint_ops
);
375 /* We need to reset 'type' in order for code in breakpoint.c to do
377 cp
->type
= bp_breakpoint
;
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 /* Deal with "catch catch", "catch throw", and "catch rethrow"
430 catch_exception_command_1 (enum exception_event_kind ex_event
,
432 int tempflag
, int from_tty
)
434 const char *cond_string
= NULL
;
438 arg
= skip_spaces (arg
);
440 std::string except_rx
= extract_exception_regexp (&arg
);
442 cond_string
= ep_parse_optional_if_clause (&arg
);
444 if ((*arg
!= '\0') && !isspace (*arg
))
445 error (_("Junk at end of arguments."));
447 if (ex_event
!= EX_EVENT_THROW
448 && ex_event
!= EX_EVENT_CATCH
449 && ex_event
!= EX_EVENT_RETHROW
)
450 error (_("Unsupported or unknown exception event; cannot catch it"));
452 handle_gnu_v3_exceptions (tempflag
, std::move (except_rx
), cond_string
,
456 /* Implementation of "catch catch" command. */
459 catch_catch_command (const char *arg
, int from_tty
,
460 struct cmd_list_element
*command
)
462 int tempflag
= get_cmd_context (command
) == CATCH_TEMPORARY
;
464 catch_exception_command_1 (EX_EVENT_CATCH
, arg
, tempflag
, from_tty
);
467 /* Implementation of "catch throw" command. */
470 catch_throw_command (const char *arg
, int from_tty
,
471 struct cmd_list_element
*command
)
473 int tempflag
= get_cmd_context (command
) == CATCH_TEMPORARY
;
475 catch_exception_command_1 (EX_EVENT_THROW
, arg
, tempflag
, from_tty
);
478 /* Implementation of "catch rethrow" command. */
481 catch_rethrow_command (const char *arg
, int from_tty
,
482 struct cmd_list_element
*command
)
484 int tempflag
= get_cmd_context (command
) == CATCH_TEMPORARY
;
486 catch_exception_command_1 (EX_EVENT_RETHROW
, arg
, tempflag
, from_tty
);
491 /* Implement the 'make_value' method for the $_exception
494 static struct value
*
495 compute_exception (struct gdbarch
*argc
, struct internalvar
*var
, void *ignore
)
497 struct value
*arg0
, *arg1
;
498 struct type
*obj_type
;
500 fetch_probe_arguments (&arg0
, &arg1
);
502 /* ARG0 is a pointer to the exception object. ARG1 is a pointer to
503 the std::type_info for the exception. Now we find the type from
504 the type_info and cast the result. */
505 obj_type
= cplus_type_from_type_info (arg1
);
506 return value_ind (value_cast (make_pointer_type (obj_type
, NULL
), arg0
));
509 /* Implementation of the '$_exception' variable. */
511 static const struct internalvar_funcs exception_funcs
=
521 initialize_throw_catchpoint_ops (void)
523 struct breakpoint_ops
*ops
;
525 initialize_breakpoint_ops ();
527 /* GNU v3 exception catchpoints. */
528 ops
= &gnu_v3_exception_catchpoint_ops
;
529 *ops
= bkpt_breakpoint_ops
;
530 ops
->re_set
= re_set_exception_catchpoint
;
531 ops
->print_it
= print_it_exception_catchpoint
;
532 ops
->print_one
= print_one_exception_catchpoint
;
533 ops
->print_mention
= print_mention_exception_catchpoint
;
534 ops
->print_recreate
= print_recreate_exception_catchpoint
;
535 ops
->print_one_detail
= print_one_detail_exception_catchpoint
;
536 ops
->check_status
= check_status_exception_catchpoint
;
540 _initialize_break_catch_throw (void)
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
);