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 std::string type_name;
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.c_str ());
184 std::swap (type_name, canon);
186 CATCH (e, RETURN_MASK_ERROR)
188 exception_print (gdb_stderr, e);
192 if (!type_name.empty ())
194 if (regexec (self->pattern, type_name.c_str (), 0, NULL, 0) != 0)
199 /* Implement the 're_set' method. */
202 re_set_exception_catchpoint (struct breakpoint *self)
204 struct symtabs_and_lines sals = {0};
205 struct symtabs_and_lines sals_end = {0};
206 struct cleanup *cleanup;
207 enum exception_event_kind kind = classify_exception_breakpoint (self);
208 struct event_location *location;
209 struct program_space *filter_pspace = current_program_space;
211 /* We first try to use the probe interface. */
215 = new_probe_location (exception_functions[kind].probe);
216 cleanup = make_cleanup_delete_event_location (location);
217 sals = parse_probes (location, filter_pspace, NULL);
218 do_cleanups (cleanup);
220 CATCH (e, RETURN_MASK_ERROR)
222 /* Using the probe interface failed. Let's fallback to the normal
226 struct explicit_location explicit_loc;
228 initialize_explicit_location (&explicit_loc);
229 explicit_loc.function_name
230 = ASTRDUP (exception_functions[kind].function);
231 location = new_explicit_location (&explicit_loc);
232 cleanup = make_cleanup_delete_event_location (location);
233 self->ops->decode_location (self, location, filter_pspace, &sals);
234 do_cleanups (cleanup);
236 CATCH (ex, RETURN_MASK_ERROR)
238 /* NOT_FOUND_ERROR just means the breakpoint will be
239 pending, so let it through. */
240 if (ex.error != NOT_FOUND_ERROR)
241 throw_exception (ex);
247 cleanup = make_cleanup (xfree, sals.sals);
248 update_breakpoint_locations (self, filter_pspace, sals, sals_end);
249 do_cleanups (cleanup);
252 static enum print_stop_action
253 print_it_exception_catchpoint (bpstat bs)
255 struct ui_out *uiout = current_uiout;
256 struct breakpoint *b = bs->breakpoint_at;
258 enum exception_event_kind kind = classify_exception_breakpoint (b);
260 annotate_catchpoint (b->number);
261 maybe_print_thread_hit_breakpoint (uiout);
263 bp_temp = b->disposition == disp_del;
264 uiout->text (bp_temp ? "Temporary catchpoint "
266 if (!uiout->is_mi_like_p ())
267 uiout->field_int ("bkptno", b->number);
268 uiout->text ((kind == EX_EVENT_THROW ? " (exception thrown), "
269 : (kind == EX_EVENT_CATCH ? " (exception caught), "
270 : " (exception rethrown), ")));
271 if (uiout->is_mi_like_p ())
273 uiout->field_string ("reason",
274 async_reason_lookup (EXEC_ASYNC_BREAKPOINT_HIT));
275 uiout->field_string ("disp", bpdisp_text (b->disposition));
276 uiout->field_int ("bkptno", b->number);
278 return PRINT_SRC_AND_LOC;
282 print_one_exception_catchpoint (struct breakpoint *b,
283 struct bp_location **last_loc)
285 struct value_print_options opts;
286 struct ui_out *uiout = current_uiout;
287 enum exception_event_kind kind = classify_exception_breakpoint (b);
289 get_user_print_options (&opts);
290 if (opts.addressprint)
293 if (b->loc == NULL || b->loc->shlib_disabled)
294 uiout->field_string ("addr", "<PENDING>");
296 uiout->field_core_addr ("addr",
297 b->loc->gdbarch, b->loc->address);
306 uiout->field_string ("what", "exception throw");
307 if (uiout->is_mi_like_p ())
308 uiout->field_string ("catch-type", "throw");
311 case EX_EVENT_RETHROW:
312 uiout->field_string ("what", "exception rethrow");
313 if (uiout->is_mi_like_p ())
314 uiout->field_string ("catch-type", "rethrow");
318 uiout->field_string ("what", "exception catch");
319 if (uiout->is_mi_like_p ())
320 uiout->field_string ("catch-type", "catch");
325 /* Implement the 'print_one_detail' method. */
328 print_one_detail_exception_catchpoint (const struct breakpoint *b,
329 struct ui_out *uiout)
331 const struct exception_catchpoint *cp
332 = (const struct exception_catchpoint *) b;
334 if (cp->exception_rx != NULL)
336 uiout->text (_("\tmatching: "));
337 uiout->field_string ("regexp", cp->exception_rx);
343 print_mention_exception_catchpoint (struct breakpoint *b)
345 struct ui_out *uiout = current_uiout;
347 enum exception_event_kind kind = classify_exception_breakpoint (b);
349 bp_temp = b->disposition == disp_del;
350 uiout->text (bp_temp ? _("Temporary catchpoint ")
352 uiout->field_int ("bkptno", b->number);
353 uiout->text ((kind == EX_EVENT_THROW ? _(" (throw)")
354 : (kind == EX_EVENT_CATCH ? _(" (catch)")
355 : _(" (rethrow)"))));
358 /* Implement the "print_recreate" breakpoint_ops method for throw and
359 catch catchpoints. */
362 print_recreate_exception_catchpoint (struct breakpoint *b,
366 enum exception_event_kind kind = classify_exception_breakpoint (b);
368 bp_temp = b->disposition == disp_del;
369 fprintf_unfiltered (fp, bp_temp ? "tcatch " : "catch ");
373 fprintf_unfiltered (fp, "throw");
376 fprintf_unfiltered (fp, "catch");
378 case EX_EVENT_RETHROW:
379 fprintf_unfiltered (fp, "rethrow");
382 print_recreate_thread (b, fp);
386 handle_gnu_v3_exceptions (int tempflag, char *except_rx, char *cond_string,
387 enum exception_event_kind ex_event, int from_tty)
389 regex_t *pattern = NULL;
391 if (except_rx != NULL)
393 pattern = XNEW (regex_t);
394 make_cleanup (xfree, pattern);
396 compile_rx_or_error (pattern, except_rx,
397 _("invalid type-matching regexp"));
400 std::unique_ptr<exception_catchpoint> cp (new exception_catchpoint ());
402 init_catchpoint (&cp->base, get_current_arch (), tempflag, cond_string,
403 &gnu_v3_exception_catchpoint_ops);
404 /* We need to reset 'type' in order for code in breakpoint.c to do
406 cp->base.type = bp_breakpoint;
408 cp->exception_rx = except_rx;
409 cp->pattern = pattern;
411 re_set_exception_catchpoint (&cp->base);
413 install_breakpoint (0, &cp->base, 1);
417 /* Look for an "if" token in *STRING. The "if" token must be preceded
420 If there is any non-whitespace text between *STRING and the "if"
421 token, then it is returned in a newly-xmalloc'd string. Otherwise,
424 STRING is updated to point to the "if" token, if it exists, or to
425 the end of the string. */
428 extract_exception_regexp (char **string)
431 char *last, *last_space;
433 start = skip_spaces (*string);
437 while (*last != '\0')
439 char *if_token = last;
441 /* Check for the "if". */
442 if (check_for_argument (&if_token, "if", 2))
445 /* No "if" token here. Skip to the next word start. */
446 last_space = skip_to_space (last);
447 last = skip_spaces (last_space);
451 if (last_space > start)
452 return savestring (start, last_space - start);
456 /* Deal with "catch catch", "catch throw", and "catch rethrow"
460 catch_exception_command_1 (enum exception_event_kind ex_event, char *arg,
461 int tempflag, int from_tty)
464 char *cond_string = NULL;
465 struct cleanup *cleanup;
469 arg = skip_spaces (arg);
471 except_rx = extract_exception_regexp (&arg);
472 cleanup = make_cleanup (xfree, except_rx);
474 cond_string = ep_parse_optional_if_clause (&arg);
476 if ((*arg != '\0') && !isspace (*arg))
477 error (_("Junk at end of arguments."));
479 if (ex_event != EX_EVENT_THROW
480 && ex_event != EX_EVENT_CATCH
481 && ex_event != EX_EVENT_RETHROW)
482 error (_("Unsupported or unknown exception event; cannot catch it"));
484 handle_gnu_v3_exceptions (tempflag, except_rx, cond_string,
487 discard_cleanups (cleanup);
490 /* Implementation of "catch catch" command. */
493 catch_catch_command (char *arg, int from_tty, struct cmd_list_element *command)
495 int tempflag = get_cmd_context (command) == CATCH_TEMPORARY;
497 catch_exception_command_1 (EX_EVENT_CATCH, arg, tempflag, from_tty);
500 /* Implementation of "catch throw" command. */
503 catch_throw_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_THROW, arg, tempflag, from_tty);
510 /* Implementation of "catch rethrow" command. */
513 catch_rethrow_command (char *arg, int from_tty,
514 struct cmd_list_element *command)
516 int tempflag = get_cmd_context (command) == CATCH_TEMPORARY;
518 catch_exception_command_1 (EX_EVENT_RETHROW, arg, tempflag, from_tty);
523 /* Implement the 'make_value' method for the $_exception
526 static struct value *
527 compute_exception (struct gdbarch *argc, struct internalvar *var, void *ignore)
529 struct value *arg0, *arg1;
530 struct type *obj_type;
532 fetch_probe_arguments (&arg0, &arg1);
534 /* ARG0 is a pointer to the exception object. ARG1 is a pointer to
535 the std::type_info for the exception. Now we find the type from
536 the type_info and cast the result. */
537 obj_type = cplus_type_from_type_info (arg1);
538 return value_ind (value_cast (make_pointer_type (obj_type, NULL), arg0));
541 /* Implementation of the '$_exception' variable. */
543 static const struct internalvar_funcs exception_funcs =
553 initialize_throw_catchpoint_ops (void)
555 struct breakpoint_ops *ops;
557 initialize_breakpoint_ops ();
559 /* GNU v3 exception catchpoints. */
560 ops = &gnu_v3_exception_catchpoint_ops;
561 *ops = bkpt_breakpoint_ops;
562 ops->dtor = dtor_exception_catchpoint;
563 ops->re_set = re_set_exception_catchpoint;
564 ops->print_it = print_it_exception_catchpoint;
565 ops->print_one = print_one_exception_catchpoint;
566 ops->print_mention = print_mention_exception_catchpoint;
567 ops->print_recreate = print_recreate_exception_catchpoint;
568 ops->print_one_detail = print_one_detail_exception_catchpoint;
569 ops->check_status = check_status_exception_catchpoint;
572 initialize_file_ftype _initialize_break_catch_throw;
575 _initialize_break_catch_throw (void)
577 initialize_throw_catchpoint_ops ();
579 /* Add catch and tcatch sub-commands. */
580 add_catch_command ("catch", _("\
581 Catch an exception, when caught."),
586 add_catch_command ("throw", _("\
587 Catch an exception, when thrown."),
592 add_catch_command ("rethrow", _("\
593 Catch an exception, when rethrown."),
594 catch_rethrow_command,
599 create_internalvar_type_lazy ("_exception", &exception_funcs, NULL);