1 /* Everything about catch/throw catchpoints, for GDB.
3 Copyright (C) 1986-2016 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;
112 pc_probe = find_probe_by_pc (pc);
113 if (pc_probe.probe == NULL
114 || strcmp (pc_probe.probe->provider, "libstdcxx") != 0
115 || (strcmp (pc_probe.probe->name, "catch") != 0
116 && strcmp (pc_probe.probe->name, "throw") != 0
117 && strcmp (pc_probe.probe->name, "rethrow") != 0))
118 error (_("not stopped at a C++ exception catchpoint"));
120 n_args = get_probe_argument_count (pc_probe.probe, frame);
122 error (_("C++ exception catchpoint has too few arguments"));
125 *arg0 = evaluate_probe_argument (pc_probe.probe, 0, frame);
126 *arg1 = evaluate_probe_argument (pc_probe.probe, 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 'dtor' method. */
148 dtor_exception_catchpoint (struct breakpoint *self)
150 struct exception_catchpoint *cp = (struct exception_catchpoint *) self;
152 xfree (cp->exception_rx);
153 if (cp->pattern != NULL)
154 regfree (cp->pattern);
155 bkpt_breakpoint_ops.dtor (self);
158 /* Implement the 'check_status' method. */
161 check_status_exception_catchpoint (struct bpstats *bs)
163 struct exception_catchpoint *self
164 = (struct exception_catchpoint *) bs->breakpoint_at;
165 char *type_name = NULL;
167 bkpt_breakpoint_ops.check_status (bs);
171 if (self->pattern == NULL)
176 struct value *typeinfo_arg;
179 fetch_probe_arguments (NULL, &typeinfo_arg);
180 type_name = cplus_typename_from_type_info (typeinfo_arg);
182 canon = cp_canonicalize_string (type_name);
189 CATCH (e, RETURN_MASK_ERROR)
191 exception_print (gdb_stderr, e);
195 if (type_name != NULL)
197 if (regexec (self->pattern, type_name, 0, NULL, 0) != 0)
204 /* Implement the 're_set' method. */
207 re_set_exception_catchpoint (struct breakpoint *self)
209 struct symtabs_and_lines sals = {0};
210 struct symtabs_and_lines sals_end = {0};
211 struct cleanup *cleanup;
212 enum exception_event_kind kind = classify_exception_breakpoint (self);
213 struct event_location *location;
214 struct program_space *filter_pspace = current_program_space;
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, filter_pspace, NULL);
223 do_cleanups (cleanup);
225 CATCH (e, RETURN_MASK_ERROR)
227 /* Using the probe interface failed. Let's fallback to the normal
231 struct explicit_location explicit_loc;
233 initialize_explicit_location (&explicit_loc);
234 explicit_loc.function_name
235 = ASTRDUP (exception_functions[kind].function);
236 location = new_explicit_location (&explicit_loc);
237 cleanup = make_cleanup_delete_event_location (location);
238 self->ops->decode_location (self, location, filter_pspace, &sals);
239 do_cleanups (cleanup);
241 CATCH (ex, RETURN_MASK_ERROR)
243 /* NOT_FOUND_ERROR just means the breakpoint will be
244 pending, so let it through. */
245 if (ex.error != NOT_FOUND_ERROR)
246 throw_exception (ex);
252 cleanup = make_cleanup (xfree, sals.sals);
253 update_breakpoint_locations (self, filter_pspace, sals, sals_end);
254 do_cleanups (cleanup);
257 static enum print_stop_action
258 print_it_exception_catchpoint (bpstat bs)
260 struct ui_out *uiout = current_uiout;
261 struct breakpoint *b = bs->breakpoint_at;
263 enum exception_event_kind kind = classify_exception_breakpoint (b);
265 annotate_catchpoint (b->number);
266 maybe_print_thread_hit_breakpoint (uiout);
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 regex_t *pattern = NULL;
398 if (except_rx != NULL)
400 pattern = XNEW (regex_t);
401 make_cleanup (xfree, pattern);
403 compile_rx_or_error (pattern, except_rx,
404 _("invalid type-matching regexp"));
407 gdb::unique_ptr<exception_catchpoint> cp (new exception_catchpoint ());
409 init_catchpoint (&cp->base, get_current_arch (), tempflag, cond_string,
410 &gnu_v3_exception_catchpoint_ops);
411 /* We need to reset 'type' in order for code in breakpoint.c to do
413 cp->base.type = bp_breakpoint;
415 cp->exception_rx = except_rx;
416 cp->pattern = pattern;
418 re_set_exception_catchpoint (&cp->base);
420 install_breakpoint (0, &cp->base, 1);
424 /* Look for an "if" token in *STRING. The "if" token must be preceded
427 If there is any non-whitespace text between *STRING and the "if"
428 token, then it is returned in a newly-xmalloc'd string. Otherwise,
431 STRING is updated to point to the "if" token, if it exists, or to
432 the end of the string. */
435 extract_exception_regexp (char **string)
438 char *last, *last_space;
440 start = skip_spaces (*string);
444 while (*last != '\0')
446 char *if_token = last;
448 /* Check for the "if". */
449 if (check_for_argument (&if_token, "if", 2))
452 /* No "if" token here. Skip to the next word start. */
453 last_space = skip_to_space (last);
454 last = skip_spaces (last_space);
458 if (last_space > start)
459 return savestring (start, last_space - start);
463 /* Deal with "catch catch", "catch throw", and "catch rethrow"
467 catch_exception_command_1 (enum exception_event_kind ex_event, char *arg,
468 int tempflag, int from_tty)
471 char *cond_string = NULL;
472 struct cleanup *cleanup;
476 arg = skip_spaces (arg);
478 except_rx = extract_exception_regexp (&arg);
479 cleanup = make_cleanup (xfree, except_rx);
481 cond_string = ep_parse_optional_if_clause (&arg);
483 if ((*arg != '\0') && !isspace (*arg))
484 error (_("Junk at end of arguments."));
486 if (ex_event != EX_EVENT_THROW
487 && ex_event != EX_EVENT_CATCH
488 && ex_event != EX_EVENT_RETHROW)
489 error (_("Unsupported or unknown exception event; cannot catch it"));
491 handle_gnu_v3_exceptions (tempflag, except_rx, cond_string,
494 discard_cleanups (cleanup);
497 /* Implementation of "catch catch" command. */
500 catch_catch_command (char *arg, int from_tty, struct cmd_list_element *command)
502 int tempflag = get_cmd_context (command) == CATCH_TEMPORARY;
504 catch_exception_command_1 (EX_EVENT_CATCH, arg, tempflag, from_tty);
507 /* Implementation of "catch throw" command. */
510 catch_throw_command (char *arg, int from_tty, struct cmd_list_element *command)
512 int tempflag = get_cmd_context (command) == CATCH_TEMPORARY;
514 catch_exception_command_1 (EX_EVENT_THROW, arg, tempflag, from_tty);
517 /* Implementation of "catch rethrow" command. */
520 catch_rethrow_command (char *arg, int from_tty,
521 struct cmd_list_element *command)
523 int tempflag = get_cmd_context (command) == CATCH_TEMPORARY;
525 catch_exception_command_1 (EX_EVENT_RETHROW, arg, tempflag, from_tty);
530 /* Implement the 'make_value' method for the $_exception
533 static struct value *
534 compute_exception (struct gdbarch *argc, struct internalvar *var, void *ignore)
536 struct value *arg0, *arg1;
537 struct type *obj_type;
539 fetch_probe_arguments (&arg0, &arg1);
541 /* ARG0 is a pointer to the exception object. ARG1 is a pointer to
542 the std::type_info for the exception. Now we find the type from
543 the type_info and cast the result. */
544 obj_type = cplus_type_from_type_info (arg1);
545 return value_ind (value_cast (make_pointer_type (obj_type, NULL), arg0));
548 /* Implementation of the '$_exception' variable. */
550 static const struct internalvar_funcs exception_funcs =
560 initialize_throw_catchpoint_ops (void)
562 struct breakpoint_ops *ops;
564 initialize_breakpoint_ops ();
566 /* GNU v3 exception catchpoints. */
567 ops = &gnu_v3_exception_catchpoint_ops;
568 *ops = bkpt_breakpoint_ops;
569 ops->dtor = dtor_exception_catchpoint;
570 ops->re_set = re_set_exception_catchpoint;
571 ops->print_it = print_it_exception_catchpoint;
572 ops->print_one = print_one_exception_catchpoint;
573 ops->print_mention = print_mention_exception_catchpoint;
574 ops->print_recreate = print_recreate_exception_catchpoint;
575 ops->print_one_detail = print_one_detail_exception_catchpoint;
576 ops->check_status = check_status_exception_catchpoint;
579 initialize_file_ftype _initialize_break_catch_throw;
582 _initialize_break_catch_throw (void)
584 initialize_throw_catchpoint_ops ();
586 /* Add catch and tcatch sub-commands. */
587 add_catch_command ("catch", _("\
588 Catch an exception, when caught."),
593 add_catch_command ("throw", _("\
594 Catch an exception, when thrown."),
599 add_catch_command ("rethrow", _("\
600 Catch an exception, when rethrown."),
601 catch_rethrow_command,
606 create_internalvar_type_lazy ("_exception", &exception_funcs, NULL);