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/>. */
22 /* Standard C includes. */
25 /* Local non-gdb includes. */
27 #include "arch-utils.h"
28 #include "breakpoint.h"
29 #include "cli/cli-utils.h"
30 #include "completer.h"
32 #include "cp-support.h"
33 #include "gdb_obstack.h"
34 #include "gdb_regex.h"
39 #include "mi/mi-common.h"
44 /* Enums for exception-handling support. */
45 enum exception_event_kind
52 /* Each spot where we may place an exception-related catchpoint has
53 two names: the SDT probe point and the function name. This
54 structure holds both. */
56 struct exception_names
58 /* The name of the probe point to try, in the form accepted by
63 /* The name of the corresponding function. */
68 /* Names of the probe points and functions on which to break. This is
69 indexed by exception_event_kind. */
70 static const struct exception_names exception_functions
[] =
72 { "-probe-stap libstdcxx:throw", "__cxa_throw" },
73 { "-probe-stap libstdcxx:rethrow", "__cxa_rethrow" },
74 { "-probe-stap libstdcxx:catch", "__cxa_begin_catch" }
77 static struct breakpoint_ops gnu_v3_exception_catchpoint_ops
;
79 /* The type of an exception catchpoint. */
81 struct exception_catchpoint
: public breakpoint
83 /* The kind of exception catchpoint. */
85 enum exception_event_kind kind
;
87 /* If not empty, a string holding the source form of the regular
88 expression to match against. */
90 std::string exception_rx
;
92 /* If non-NULL, a compiled regular expression which is used to
93 determine which exceptions to stop on. */
95 std::unique_ptr
<compiled_regex
> pattern
;
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
.prob
== NULL
114 || pc_probe
.prob
->get_provider () != "libstdcxx"
115 || (pc_probe
.prob
->get_name () != "catch"
116 && pc_probe
.prob
->get_name () != "throw"
117 && pc_probe
.prob
->get_name () != "rethrow"))
118 error (_("not stopped at a C++ exception catchpoint"));
120 n_args
= pc_probe
.prob
->get_argument_count (frame
);
122 error (_("C++ exception catchpoint has too few arguments"));
125 *arg0
= pc_probe
.prob
->evaluate_argument (0, frame
);
126 *arg1
= pc_probe
.prob
->evaluate_argument (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 'check_status' method. */
148 check_status_exception_catchpoint (struct bpstats
*bs
)
150 struct exception_catchpoint
*self
151 = (struct exception_catchpoint
*) bs
->breakpoint_at
;
152 std::string type_name
;
154 bkpt_breakpoint_ops
.check_status (bs
);
158 if (self
->pattern
== NULL
)
163 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 ());
171 std::swap (type_name
, canon
);
173 CATCH (e
, RETURN_MASK_ERROR
)
175 exception_print (gdb_stderr
, e
);
179 if (!type_name
.empty ())
181 if (self
->pattern
->exec (type_name
.c_str (), 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 (e
, RETURN_MASK_ERROR
)
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 (ex
, RETURN_MASK_ERROR
)
219 /* NOT_FOUND_ERROR just means the breakpoint will be
220 pending, so let it through. */
221 if (ex
.error
!= NOT_FOUND_ERROR
)
222 throw_exception (ex
);
228 update_breakpoint_locations (self
, filter_pspace
, sals
, {});
231 static enum print_stop_action
232 print_it_exception_catchpoint (bpstat bs
)
234 struct ui_out
*uiout
= current_uiout
;
235 struct breakpoint
*b
= bs
->breakpoint_at
;
237 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
239 annotate_catchpoint (b
->number
);
240 maybe_print_thread_hit_breakpoint (uiout
);
242 bp_temp
= b
->disposition
== disp_del
;
243 uiout
->text (bp_temp
? "Temporary catchpoint "
245 uiout
->field_int ("bkptno", b
->number
);
246 uiout
->text ((kind
== EX_EVENT_THROW
? " (exception thrown), "
247 : (kind
== EX_EVENT_CATCH
? " (exception caught), "
248 : " (exception rethrown), ")));
249 if (uiout
->is_mi_like_p ())
251 uiout
->field_string ("reason",
252 async_reason_lookup (EXEC_ASYNC_BREAKPOINT_HIT
));
253 uiout
->field_string ("disp", bpdisp_text (b
->disposition
));
255 return PRINT_SRC_AND_LOC
;
259 print_one_exception_catchpoint (struct breakpoint
*b
,
260 struct bp_location
**last_loc
)
262 struct value_print_options opts
;
263 struct ui_out
*uiout
= current_uiout
;
264 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
266 get_user_print_options (&opts
);
267 if (opts
.addressprint
)
270 if (b
->loc
== NULL
|| b
->loc
->shlib_disabled
)
271 uiout
->field_string ("addr", "<PENDING>");
273 uiout
->field_core_addr ("addr",
274 b
->loc
->gdbarch
, b
->loc
->address
);
283 uiout
->field_string ("what", "exception throw");
284 if (uiout
->is_mi_like_p ())
285 uiout
->field_string ("catch-type", "throw");
288 case EX_EVENT_RETHROW
:
289 uiout
->field_string ("what", "exception rethrow");
290 if (uiout
->is_mi_like_p ())
291 uiout
->field_string ("catch-type", "rethrow");
295 uiout
->field_string ("what", "exception catch");
296 if (uiout
->is_mi_like_p ())
297 uiout
->field_string ("catch-type", "catch");
302 /* Implement the 'print_one_detail' method. */
305 print_one_detail_exception_catchpoint (const struct breakpoint
*b
,
306 struct ui_out
*uiout
)
308 const struct exception_catchpoint
*cp
309 = (const struct exception_catchpoint
*) b
;
311 if (!cp
->exception_rx
.empty ())
313 uiout
->text (_("\tmatching: "));
314 uiout
->field_string ("regexp", cp
->exception_rx
.c_str ());
320 print_mention_exception_catchpoint (struct breakpoint
*b
)
322 struct ui_out
*uiout
= current_uiout
;
324 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
326 bp_temp
= b
->disposition
== disp_del
;
327 uiout
->text (bp_temp
? _("Temporary catchpoint ")
329 uiout
->field_int ("bkptno", b
->number
);
330 uiout
->text ((kind
== EX_EVENT_THROW
? _(" (throw)")
331 : (kind
== EX_EVENT_CATCH
? _(" (catch)")
332 : _(" (rethrow)"))));
335 /* Implement the "print_recreate" breakpoint_ops method for throw and
336 catch catchpoints. */
339 print_recreate_exception_catchpoint (struct breakpoint
*b
,
343 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
345 bp_temp
= b
->disposition
== disp_del
;
346 fprintf_unfiltered (fp
, bp_temp
? "tcatch " : "catch ");
350 fprintf_unfiltered (fp
, "throw");
353 fprintf_unfiltered (fp
, "catch");
355 case EX_EVENT_RETHROW
:
356 fprintf_unfiltered (fp
, "rethrow");
359 print_recreate_thread (b
, fp
);
363 handle_gnu_v3_exceptions (int tempflag
, std::string
&&except_rx
,
364 const char *cond_string
,
365 enum exception_event_kind ex_event
, int from_tty
)
367 std::unique_ptr
<compiled_regex
> pattern
;
369 if (!except_rx
.empty ())
371 pattern
.reset (new compiled_regex (except_rx
.c_str (), REG_NOSUB
,
372 _("invalid type-matching regexp")));
375 std::unique_ptr
<exception_catchpoint
> cp (new exception_catchpoint ());
377 init_catchpoint (cp
.get (), get_current_arch (), tempflag
, cond_string
,
378 &gnu_v3_exception_catchpoint_ops
);
379 /* We need to reset 'type' in order for code in breakpoint.c to do
381 cp
->type
= bp_breakpoint
;
383 cp
->exception_rx
= std::move (except_rx
);
384 cp
->pattern
= std::move (pattern
);
386 re_set_exception_catchpoint (cp
.get ());
388 install_breakpoint (0, std::move (cp
), 1);
391 /* Look for an "if" token in *STRING. The "if" token must be preceded
394 If there is any non-whitespace text between *STRING and the "if"
395 token, then it is returned in a newly-xmalloc'd string. Otherwise,
398 STRING is updated to point to the "if" token, if it exists, or to
399 the end of the string. */
402 extract_exception_regexp (const char **string
)
405 const char *last
, *last_space
;
407 start
= skip_spaces (*string
);
411 while (*last
!= '\0')
413 const char *if_token
= last
;
415 /* Check for the "if". */
416 if (check_for_argument (&if_token
, "if", 2))
419 /* No "if" token here. Skip to the next word start. */
420 last_space
= skip_to_space (last
);
421 last
= skip_spaces (last_space
);
425 if (last_space
> start
)
426 return std::string (start
, last_space
- start
);
427 return std::string ();
430 /* Deal with "catch catch", "catch throw", and "catch rethrow"
434 catch_exception_command_1 (enum exception_event_kind ex_event
,
436 int tempflag
, int from_tty
)
438 const char *cond_string
= NULL
;
442 arg
= skip_spaces (arg
);
444 std::string except_rx
= extract_exception_regexp (&arg
);
446 cond_string
= ep_parse_optional_if_clause (&arg
);
448 if ((*arg
!= '\0') && !isspace (*arg
))
449 error (_("Junk at end of arguments."));
451 if (ex_event
!= EX_EVENT_THROW
452 && ex_event
!= EX_EVENT_CATCH
453 && ex_event
!= EX_EVENT_RETHROW
)
454 error (_("Unsupported or unknown exception event; cannot catch it"));
456 handle_gnu_v3_exceptions (tempflag
, std::move (except_rx
), cond_string
,
460 /* Implementation of "catch catch" command. */
463 catch_catch_command (const char *arg
, int from_tty
,
464 struct cmd_list_element
*command
)
466 int tempflag
= get_cmd_context (command
) == CATCH_TEMPORARY
;
468 catch_exception_command_1 (EX_EVENT_CATCH
, arg
, tempflag
, from_tty
);
471 /* Implementation of "catch throw" command. */
474 catch_throw_command (const char *arg
, int from_tty
,
475 struct cmd_list_element
*command
)
477 int tempflag
= get_cmd_context (command
) == CATCH_TEMPORARY
;
479 catch_exception_command_1 (EX_EVENT_THROW
, arg
, tempflag
, from_tty
);
482 /* Implementation of "catch rethrow" command. */
485 catch_rethrow_command (const char *arg
, int from_tty
,
486 struct cmd_list_element
*command
)
488 int tempflag
= get_cmd_context (command
) == CATCH_TEMPORARY
;
490 catch_exception_command_1 (EX_EVENT_RETHROW
, arg
, tempflag
, from_tty
);
495 /* Implement the 'make_value' method for the $_exception
498 static struct value
*
499 compute_exception (struct gdbarch
*argc
, struct internalvar
*var
, void *ignore
)
501 struct value
*arg0
, *arg1
;
502 struct type
*obj_type
;
504 fetch_probe_arguments (&arg0
, &arg1
);
506 /* ARG0 is a pointer to the exception object. ARG1 is a pointer to
507 the std::type_info for the exception. Now we find the type from
508 the type_info and cast the result. */
509 obj_type
= cplus_type_from_type_info (arg1
);
510 return value_ind (value_cast (make_pointer_type (obj_type
, NULL
), arg0
));
513 /* Implementation of the '$_exception' variable. */
515 static const struct internalvar_funcs exception_funcs
=
525 initialize_throw_catchpoint_ops (void)
527 struct breakpoint_ops
*ops
;
529 initialize_breakpoint_ops ();
531 /* GNU v3 exception catchpoints. */
532 ops
= &gnu_v3_exception_catchpoint_ops
;
533 *ops
= bkpt_breakpoint_ops
;
534 ops
->re_set
= re_set_exception_catchpoint
;
535 ops
->print_it
= print_it_exception_catchpoint
;
536 ops
->print_one
= print_one_exception_catchpoint
;
537 ops
->print_mention
= print_mention_exception_catchpoint
;
538 ops
->print_recreate
= print_recreate_exception_catchpoint
;
539 ops
->print_one_detail
= print_one_detail_exception_catchpoint
;
540 ops
->check_status
= check_status_exception_catchpoint
;
544 _initialize_break_catch_throw (void)
546 initialize_throw_catchpoint_ops ();
548 /* Add catch and tcatch sub-commands. */
549 add_catch_command ("catch", _("\
550 Catch an exception, when caught."),
555 add_catch_command ("throw", _("\
556 Catch an exception, when thrown."),
561 add_catch_command ("rethrow", _("\
562 Catch an exception, when rethrown."),
563 catch_rethrow_command
,
568 create_internalvar_type_lazy ("_exception", &exception_funcs
, NULL
);