1 /* Everything about catch/throw catchpoints, for GDB.
3 Copyright (C) 1986-2015 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
;
110 const struct sym_probe_fns
*pc_probe_fns
;
113 pc_probe
= find_probe_by_pc (pc
);
114 if (pc_probe
.probe
== NULL
115 || strcmp (pc_probe
.probe
->provider
, "libstdcxx") != 0
116 || (strcmp (pc_probe
.probe
->name
, "catch") != 0
117 && strcmp (pc_probe
.probe
->name
, "throw") != 0
118 && strcmp (pc_probe
.probe
->name
, "rethrow") != 0))
119 error (_("not stopped at a C++ exception catchpoint"));
121 n_args
= get_probe_argument_count (pc_probe
.probe
, frame
);
123 error (_("C++ exception catchpoint has too few arguments"));
126 *arg0
= evaluate_probe_argument (pc_probe
.probe
, 0, frame
);
127 *arg1
= evaluate_probe_argument (pc_probe
.probe
, 1, frame
);
129 if ((arg0
!= NULL
&& *arg0
== NULL
) || *arg1
== NULL
)
130 error (_("error computing probe argument at c++ exception catchpoint"));
135 /* A helper function that returns a value indicating the kind of the
136 exception catchpoint B. */
138 static enum exception_event_kind
139 classify_exception_breakpoint (struct breakpoint
*b
)
141 struct exception_catchpoint
*cp
= (struct exception_catchpoint
*) b
;
146 /* Implement the 'dtor' method. */
149 dtor_exception_catchpoint (struct breakpoint
*self
)
151 struct exception_catchpoint
*cp
= (struct exception_catchpoint
*) self
;
153 xfree (cp
->exception_rx
);
154 if (cp
->pattern
!= NULL
)
155 regfree (cp
->pattern
);
156 bkpt_breakpoint_ops
.dtor (self
);
159 /* Implement the 'check_status' method. */
162 check_status_exception_catchpoint (struct bpstats
*bs
)
164 struct exception_catchpoint
*self
165 = (struct exception_catchpoint
*) bs
->breakpoint_at
;
166 char *type_name
= NULL
;
168 bkpt_breakpoint_ops
.check_status (bs
);
172 if (self
->pattern
== NULL
)
177 struct value
*typeinfo_arg
;
180 fetch_probe_arguments (NULL
, &typeinfo_arg
);
181 type_name
= cplus_typename_from_type_info (typeinfo_arg
);
183 canon
= cp_canonicalize_string (type_name
);
190 CATCH (e
, RETURN_MASK_ERROR
)
192 exception_print (gdb_stderr
, e
);
196 if (type_name
!= NULL
)
198 if (regexec (self
->pattern
, type_name
, 0, NULL
, 0) != 0)
205 /* Implement the 're_set' method. */
208 re_set_exception_catchpoint (struct breakpoint
*self
)
210 struct symtabs_and_lines sals
= {0};
211 struct symtabs_and_lines sals_end
= {0};
212 struct cleanup
*cleanup
;
213 enum exception_event_kind kind
= classify_exception_breakpoint (self
);
214 struct event_location
*location
;
216 /* We first try to use the probe interface. */
220 = new_probe_location (exception_functions
[kind
].probe
);
221 cleanup
= make_cleanup_delete_event_location (location
);
222 sals
= parse_probes (location
, NULL
);
223 do_cleanups (cleanup
);
226 CATCH (e
, RETURN_MASK_ERROR
)
228 /* Using the probe interface failed. Let's fallback to the normal
232 struct explicit_location explicit_loc
;
234 initialize_explicit_location (&explicit_loc
);
235 explicit_loc
.function_name
236 = ASTRDUP (exception_functions
[kind
].function
);
237 location
= new_explicit_location (&explicit_loc
);
238 cleanup
= make_cleanup_delete_event_location (location
);
239 self
->ops
->decode_location (self
, location
, &sals
);
240 do_cleanups (cleanup
);
242 CATCH (ex
, RETURN_MASK_ERROR
)
244 /* NOT_FOUND_ERROR just means the breakpoint will be
245 pending, so let it through. */
246 if (ex
.error
!= NOT_FOUND_ERROR
)
247 throw_exception (ex
);
253 cleanup
= make_cleanup (xfree
, sals
.sals
);
254 update_breakpoint_locations (self
, sals
, sals_end
);
255 do_cleanups (cleanup
);
258 static enum print_stop_action
259 print_it_exception_catchpoint (bpstat bs
)
261 struct ui_out
*uiout
= current_uiout
;
262 struct breakpoint
*b
= bs
->breakpoint_at
;
264 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
266 annotate_catchpoint (b
->number
);
268 bp_temp
= b
->disposition
== disp_del
;
270 bp_temp
? "Temporary catchpoint "
272 if (!ui_out_is_mi_like_p (uiout
))
273 ui_out_field_int (uiout
, "bkptno", b
->number
);
275 (kind
== EX_EVENT_THROW
? " (exception thrown), "
276 : (kind
== EX_EVENT_CATCH
? " (exception caught), "
277 : " (exception rethrown), ")));
278 if (ui_out_is_mi_like_p (uiout
))
280 ui_out_field_string (uiout
, "reason",
281 async_reason_lookup (EXEC_ASYNC_BREAKPOINT_HIT
));
282 ui_out_field_string (uiout
, "disp", bpdisp_text (b
->disposition
));
283 ui_out_field_int (uiout
, "bkptno", b
->number
);
285 return PRINT_SRC_AND_LOC
;
289 print_one_exception_catchpoint (struct breakpoint
*b
,
290 struct bp_location
**last_loc
)
292 struct value_print_options opts
;
293 struct ui_out
*uiout
= current_uiout
;
294 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
296 get_user_print_options (&opts
);
297 if (opts
.addressprint
)
300 if (b
->loc
== NULL
|| b
->loc
->shlib_disabled
)
301 ui_out_field_string (uiout
, "addr", "<PENDING>");
303 ui_out_field_core_addr (uiout
, "addr",
304 b
->loc
->gdbarch
, b
->loc
->address
);
313 ui_out_field_string (uiout
, "what", "exception throw");
314 if (ui_out_is_mi_like_p (uiout
))
315 ui_out_field_string (uiout
, "catch-type", "throw");
318 case EX_EVENT_RETHROW
:
319 ui_out_field_string (uiout
, "what", "exception rethrow");
320 if (ui_out_is_mi_like_p (uiout
))
321 ui_out_field_string (uiout
, "catch-type", "rethrow");
325 ui_out_field_string (uiout
, "what", "exception catch");
326 if (ui_out_is_mi_like_p (uiout
))
327 ui_out_field_string (uiout
, "catch-type", "catch");
332 /* Implement the 'print_one_detail' method. */
335 print_one_detail_exception_catchpoint (const struct breakpoint
*b
,
336 struct ui_out
*uiout
)
338 const struct exception_catchpoint
*cp
339 = (const struct exception_catchpoint
*) b
;
341 if (cp
->exception_rx
!= NULL
)
343 ui_out_text (uiout
, _("\tmatching: "));
344 ui_out_field_string (uiout
, "regexp", cp
->exception_rx
);
345 ui_out_text (uiout
, "\n");
350 print_mention_exception_catchpoint (struct breakpoint
*b
)
352 struct ui_out
*uiout
= current_uiout
;
354 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
356 bp_temp
= b
->disposition
== disp_del
;
357 ui_out_text (uiout
, bp_temp
? _("Temporary catchpoint ")
359 ui_out_field_int (uiout
, "bkptno", b
->number
);
360 ui_out_text (uiout
, (kind
== EX_EVENT_THROW
? _(" (throw)")
361 : (kind
== EX_EVENT_CATCH
? _(" (catch)")
362 : _(" (rethrow)"))));
365 /* Implement the "print_recreate" breakpoint_ops method for throw and
366 catch catchpoints. */
369 print_recreate_exception_catchpoint (struct breakpoint
*b
,
373 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
375 bp_temp
= b
->disposition
== disp_del
;
376 fprintf_unfiltered (fp
, bp_temp
? "tcatch " : "catch ");
380 fprintf_unfiltered (fp
, "throw");
383 fprintf_unfiltered (fp
, "catch");
385 case EX_EVENT_RETHROW
:
386 fprintf_unfiltered (fp
, "rethrow");
389 print_recreate_thread (b
, fp
);
393 handle_gnu_v3_exceptions (int tempflag
, char *except_rx
, char *cond_string
,
394 enum exception_event_kind ex_event
, int from_tty
)
396 struct exception_catchpoint
*cp
;
397 struct cleanup
*cleanup
= make_cleanup (null_cleanup
, NULL
);
398 regex_t
*pattern
= NULL
;
400 if (except_rx
!= NULL
)
402 pattern
= XNEW (regex_t
);
403 make_cleanup (xfree
, pattern
);
405 compile_rx_or_error (pattern
, except_rx
,
406 _("invalid type-matching regexp"));
409 cp
= XCNEW (struct exception_catchpoint
);
410 make_cleanup (xfree
, cp
);
412 init_catchpoint (&cp
->base
, get_current_arch (), tempflag
, cond_string
,
413 &gnu_v3_exception_catchpoint_ops
);
414 /* We need to reset 'type' in order for code in breakpoint.c to do
416 cp
->base
.type
= bp_breakpoint
;
418 cp
->exception_rx
= except_rx
;
419 cp
->pattern
= pattern
;
421 re_set_exception_catchpoint (&cp
->base
);
423 install_breakpoint (0, &cp
->base
, 1);
424 discard_cleanups (cleanup
);
427 /* Look for an "if" token in *STRING. The "if" token must be preceded
430 If there is any non-whitespace text between *STRING and the "if"
431 token, then it is returned in a newly-xmalloc'd string. Otherwise,
434 STRING is updated to point to the "if" token, if it exists, or to
435 the end of the string. */
438 extract_exception_regexp (char **string
)
441 char *last
, *last_space
;
443 start
= skip_spaces (*string
);
447 while (*last
!= '\0')
449 char *if_token
= last
;
451 /* Check for the "if". */
452 if (check_for_argument (&if_token
, "if", 2))
455 /* No "if" token here. Skip to the next word start. */
456 last_space
= skip_to_space (last
);
457 last
= skip_spaces (last_space
);
461 if (last_space
> start
)
462 return savestring (start
, last_space
- start
);
466 /* Deal with "catch catch", "catch throw", and "catch rethrow"
470 catch_exception_command_1 (enum exception_event_kind ex_event
, char *arg
,
471 int tempflag
, int from_tty
)
474 char *cond_string
= NULL
;
475 struct cleanup
*cleanup
;
479 arg
= skip_spaces (arg
);
481 except_rx
= extract_exception_regexp (&arg
);
482 cleanup
= make_cleanup (xfree
, except_rx
);
484 cond_string
= ep_parse_optional_if_clause (&arg
);
486 if ((*arg
!= '\0') && !isspace (*arg
))
487 error (_("Junk at end of arguments."));
489 if (ex_event
!= EX_EVENT_THROW
490 && ex_event
!= EX_EVENT_CATCH
491 && ex_event
!= EX_EVENT_RETHROW
)
492 error (_("Unsupported or unknown exception event; cannot catch it"));
494 handle_gnu_v3_exceptions (tempflag
, except_rx
, cond_string
,
497 discard_cleanups (cleanup
);
500 /* Implementation of "catch catch" command. */
503 catch_catch_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_CATCH
, arg
, tempflag
, from_tty
);
510 /* Implementation of "catch throw" command. */
513 catch_throw_command (char *arg
, int from_tty
, struct cmd_list_element
*command
)
515 int tempflag
= get_cmd_context (command
) == CATCH_TEMPORARY
;
517 catch_exception_command_1 (EX_EVENT_THROW
, arg
, tempflag
, from_tty
);
520 /* Implementation of "catch rethrow" command. */
523 catch_rethrow_command (char *arg
, int from_tty
,
524 struct cmd_list_element
*command
)
526 int tempflag
= get_cmd_context (command
) == CATCH_TEMPORARY
;
528 catch_exception_command_1 (EX_EVENT_RETHROW
, arg
, tempflag
, from_tty
);
533 /* Implement the 'make_value' method for the $_exception
536 static struct value
*
537 compute_exception (struct gdbarch
*argc
, struct internalvar
*var
, void *ignore
)
539 struct value
*arg0
, *arg1
;
540 struct type
*obj_type
;
542 fetch_probe_arguments (&arg0
, &arg1
);
544 /* ARG0 is a pointer to the exception object. ARG1 is a pointer to
545 the std::type_info for the exception. Now we find the type from
546 the type_info and cast the result. */
547 obj_type
= cplus_type_from_type_info (arg1
);
548 return value_ind (value_cast (make_pointer_type (obj_type
, NULL
), arg0
));
551 /* Implementation of the '$_exception' variable. */
553 static const struct internalvar_funcs exception_funcs
=
563 initialize_throw_catchpoint_ops (void)
565 struct breakpoint_ops
*ops
;
567 initialize_breakpoint_ops ();
569 /* GNU v3 exception catchpoints. */
570 ops
= &gnu_v3_exception_catchpoint_ops
;
571 *ops
= bkpt_breakpoint_ops
;
572 ops
->dtor
= dtor_exception_catchpoint
;
573 ops
->re_set
= re_set_exception_catchpoint
;
574 ops
->print_it
= print_it_exception_catchpoint
;
575 ops
->print_one
= print_one_exception_catchpoint
;
576 ops
->print_mention
= print_mention_exception_catchpoint
;
577 ops
->print_recreate
= print_recreate_exception_catchpoint
;
578 ops
->print_one_detail
= print_one_detail_exception_catchpoint
;
579 ops
->check_status
= check_status_exception_catchpoint
;
582 initialize_file_ftype _initialize_break_catch_throw
;
585 _initialize_break_catch_throw (void)
587 initialize_throw_catchpoint_ops ();
589 /* Add catch and tcatch sub-commands. */
590 add_catch_command ("catch", _("\
591 Catch an exception, when caught."),
596 add_catch_command ("throw", _("\
597 Catch an exception, when thrown."),
602 add_catch_command ("rethrow", _("\
603 Catch an exception, when rethrown."),
604 catch_rethrow_command
,
609 create_internalvar_type_lazy ("_exception", &exception_funcs
, NULL
);