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 char *spec = ASTRDUP (exception_functions[kind].function);
234 location = new_linespec_location (&spec);
235 cleanup = make_cleanup_delete_event_location (location);
236 self->ops->decode_location (self, location, &sals);
237 do_cleanups (cleanup);
239 CATCH (ex, RETURN_MASK_ERROR)
241 /* NOT_FOUND_ERROR just means the breakpoint will be
242 pending, so let it through. */
243 if (ex.error != NOT_FOUND_ERROR)
244 throw_exception (ex);
250 cleanup = make_cleanup (xfree, sals.sals);
251 update_breakpoint_locations (self, sals, sals_end);
252 do_cleanups (cleanup);
255 static enum print_stop_action
256 print_it_exception_catchpoint (bpstat bs)
258 struct ui_out *uiout = current_uiout;
259 struct breakpoint *b = bs->breakpoint_at;
261 enum exception_event_kind kind = classify_exception_breakpoint (b);
263 annotate_catchpoint (b->number);
265 bp_temp = b->disposition == disp_del;
267 bp_temp ? "Temporary catchpoint "
269 if (!ui_out_is_mi_like_p (uiout))
270 ui_out_field_int (uiout, "bkptno", b->number);
272 (kind == EX_EVENT_THROW ? " (exception thrown), "
273 : (kind == EX_EVENT_CATCH ? " (exception caught), "
274 : " (exception rethrown), ")));
275 if (ui_out_is_mi_like_p (uiout))
277 ui_out_field_string (uiout, "reason",
278 async_reason_lookup (EXEC_ASYNC_BREAKPOINT_HIT));
279 ui_out_field_string (uiout, "disp", bpdisp_text (b->disposition));
280 ui_out_field_int (uiout, "bkptno", b->number);
282 return PRINT_SRC_AND_LOC;
286 print_one_exception_catchpoint (struct breakpoint *b,
287 struct bp_location **last_loc)
289 struct value_print_options opts;
290 struct ui_out *uiout = current_uiout;
291 enum exception_event_kind kind = classify_exception_breakpoint (b);
293 get_user_print_options (&opts);
294 if (opts.addressprint)
297 if (b->loc == NULL || b->loc->shlib_disabled)
298 ui_out_field_string (uiout, "addr", "<PENDING>");
300 ui_out_field_core_addr (uiout, "addr",
301 b->loc->gdbarch, b->loc->address);
310 ui_out_field_string (uiout, "what", "exception throw");
311 if (ui_out_is_mi_like_p (uiout))
312 ui_out_field_string (uiout, "catch-type", "throw");
315 case EX_EVENT_RETHROW:
316 ui_out_field_string (uiout, "what", "exception rethrow");
317 if (ui_out_is_mi_like_p (uiout))
318 ui_out_field_string (uiout, "catch-type", "rethrow");
322 ui_out_field_string (uiout, "what", "exception catch");
323 if (ui_out_is_mi_like_p (uiout))
324 ui_out_field_string (uiout, "catch-type", "catch");
329 /* Implement the 'print_one_detail' method. */
332 print_one_detail_exception_catchpoint (const struct breakpoint *b,
333 struct ui_out *uiout)
335 const struct exception_catchpoint *cp
336 = (const struct exception_catchpoint *) b;
338 if (cp->exception_rx != NULL)
340 ui_out_text (uiout, _("\tmatching: "));
341 ui_out_field_string (uiout, "regexp", cp->exception_rx);
342 ui_out_text (uiout, "\n");
347 print_mention_exception_catchpoint (struct breakpoint *b)
349 struct ui_out *uiout = current_uiout;
351 enum exception_event_kind kind = classify_exception_breakpoint (b);
353 bp_temp = b->disposition == disp_del;
354 ui_out_text (uiout, bp_temp ? _("Temporary catchpoint ")
356 ui_out_field_int (uiout, "bkptno", b->number);
357 ui_out_text (uiout, (kind == EX_EVENT_THROW ? _(" (throw)")
358 : (kind == EX_EVENT_CATCH ? _(" (catch)")
359 : _(" (rethrow)"))));
362 /* Implement the "print_recreate" breakpoint_ops method for throw and
363 catch catchpoints. */
366 print_recreate_exception_catchpoint (struct breakpoint *b,
370 enum exception_event_kind kind = classify_exception_breakpoint (b);
372 bp_temp = b->disposition == disp_del;
373 fprintf_unfiltered (fp, bp_temp ? "tcatch " : "catch ");
377 fprintf_unfiltered (fp, "throw");
380 fprintf_unfiltered (fp, "catch");
382 case EX_EVENT_RETHROW:
383 fprintf_unfiltered (fp, "rethrow");
386 print_recreate_thread (b, fp);
390 handle_gnu_v3_exceptions (int tempflag, char *except_rx, char *cond_string,
391 enum exception_event_kind ex_event, int from_tty)
393 struct exception_catchpoint *cp;
394 struct cleanup *cleanup = make_cleanup (null_cleanup, NULL);
395 regex_t *pattern = NULL;
397 if (except_rx != NULL)
399 pattern = XNEW (regex_t);
400 make_cleanup (xfree, pattern);
402 compile_rx_or_error (pattern, except_rx,
403 _("invalid type-matching regexp"));
406 cp = XCNEW (struct exception_catchpoint);
407 make_cleanup (xfree, cp);
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);
421 discard_cleanups (cleanup);
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);