1 /* Everything about catch/throw catchpoints, for GDB.
3 Copyright (C) 1986-2017 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
: public breakpoint
79 /* The kind of exception catchpoint. */
81 enum exception_event_kind kind
;
83 /* If not empty, a string holding the source form of the regular
84 expression to match against. */
86 std::string exception_rx
;
88 /* If non-NULL, a compiled regular expression which is used to
89 determine which exceptions to stop on. */
91 std::unique_ptr
<compiled_regex
> pattern
;
96 /* A helper function that fetches exception probe arguments. This
97 fills in *ARG0 (if non-NULL) and *ARG1 (which must be non-NULL).
98 It will throw an exception on any kind of failure. */
101 fetch_probe_arguments (struct value
**arg0
, struct value
**arg1
)
103 struct frame_info
*frame
= get_selected_frame (_("No frame selected"));
104 CORE_ADDR pc
= get_frame_pc (frame
);
105 struct bound_probe pc_probe
;
108 pc_probe
= find_probe_by_pc (pc
);
109 if (pc_probe
.probe
== NULL
110 || strcmp (pc_probe
.probe
->provider
, "libstdcxx") != 0
111 || (strcmp (pc_probe
.probe
->name
, "catch") != 0
112 && strcmp (pc_probe
.probe
->name
, "throw") != 0
113 && strcmp (pc_probe
.probe
->name
, "rethrow") != 0))
114 error (_("not stopped at a C++ exception catchpoint"));
116 n_args
= get_probe_argument_count (pc_probe
.probe
, frame
);
118 error (_("C++ exception catchpoint has too few arguments"));
121 *arg0
= evaluate_probe_argument (pc_probe
.probe
, 0, frame
);
122 *arg1
= evaluate_probe_argument (pc_probe
.probe
, 1, frame
);
124 if ((arg0
!= NULL
&& *arg0
== NULL
) || *arg1
== NULL
)
125 error (_("error computing probe argument at c++ exception catchpoint"));
130 /* A helper function that returns a value indicating the kind of the
131 exception catchpoint B. */
133 static enum exception_event_kind
134 classify_exception_breakpoint (struct breakpoint
*b
)
136 struct exception_catchpoint
*cp
= (struct exception_catchpoint
*) b
;
141 /* Implement the 'check_status' method. */
144 check_status_exception_catchpoint (struct bpstats
*bs
)
146 struct exception_catchpoint
*self
147 = (struct exception_catchpoint
*) bs
->breakpoint_at
;
148 std::string type_name
;
150 bkpt_breakpoint_ops
.check_status (bs
);
154 if (self
->pattern
== NULL
)
159 struct value
*typeinfo_arg
;
162 fetch_probe_arguments (NULL
, &typeinfo_arg
);
163 type_name
= cplus_typename_from_type_info (typeinfo_arg
);
165 canon
= cp_canonicalize_string (type_name
.c_str ());
167 std::swap (type_name
, canon
);
169 CATCH (e
, RETURN_MASK_ERROR
)
171 exception_print (gdb_stderr
, e
);
175 if (!type_name
.empty ())
177 if (self
->pattern
->exec (type_name
.c_str (), 0, NULL
, 0) != 0)
182 /* Implement the 're_set' method. */
185 re_set_exception_catchpoint (struct breakpoint
*self
)
187 struct symtabs_and_lines sals
= {0};
188 struct symtabs_and_lines sals_end
= {0};
189 struct cleanup
*cleanup
;
190 enum exception_event_kind kind
= classify_exception_breakpoint (self
);
191 struct program_space
*filter_pspace
= current_program_space
;
193 /* We first try to use the probe interface. */
196 event_location_up location
197 = new_probe_location (exception_functions
[kind
].probe
);
198 sals
= parse_probes (location
.get (), filter_pspace
, NULL
);
200 CATCH (e
, RETURN_MASK_ERROR
)
202 /* Using the probe interface failed. Let's fallback to the normal
206 struct explicit_location explicit_loc
;
208 initialize_explicit_location (&explicit_loc
);
209 explicit_loc
.function_name
210 = ASTRDUP (exception_functions
[kind
].function
);
211 event_location_up location
= new_explicit_location (&explicit_loc
);
212 self
->ops
->decode_location (self
, location
.get (), filter_pspace
,
215 CATCH (ex
, RETURN_MASK_ERROR
)
217 /* NOT_FOUND_ERROR just means the breakpoint will be
218 pending, so let it through. */
219 if (ex
.error
!= NOT_FOUND_ERROR
)
220 throw_exception (ex
);
226 cleanup
= make_cleanup (xfree
, sals
.sals
);
227 update_breakpoint_locations (self
, filter_pspace
, sals
, sals_end
);
228 do_cleanups (cleanup
);
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 if (!uiout
->is_mi_like_p ())
246 uiout
->field_int ("bkptno", b
->number
);
247 uiout
->text ((kind
== EX_EVENT_THROW
? " (exception thrown), "
248 : (kind
== EX_EVENT_CATCH
? " (exception caught), "
249 : " (exception rethrown), ")));
250 if (uiout
->is_mi_like_p ())
252 uiout
->field_string ("reason",
253 async_reason_lookup (EXEC_ASYNC_BREAKPOINT_HIT
));
254 uiout
->field_string ("disp", bpdisp_text (b
->disposition
));
255 uiout
->field_int ("bkptno", b
->number
);
257 return PRINT_SRC_AND_LOC
;
261 print_one_exception_catchpoint (struct breakpoint
*b
,
262 struct bp_location
**last_loc
)
264 struct value_print_options opts
;
265 struct ui_out
*uiout
= current_uiout
;
266 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
268 get_user_print_options (&opts
);
269 if (opts
.addressprint
)
272 if (b
->loc
== NULL
|| b
->loc
->shlib_disabled
)
273 uiout
->field_string ("addr", "<PENDING>");
275 uiout
->field_core_addr ("addr",
276 b
->loc
->gdbarch
, b
->loc
->address
);
285 uiout
->field_string ("what", "exception throw");
286 if (uiout
->is_mi_like_p ())
287 uiout
->field_string ("catch-type", "throw");
290 case EX_EVENT_RETHROW
:
291 uiout
->field_string ("what", "exception rethrow");
292 if (uiout
->is_mi_like_p ())
293 uiout
->field_string ("catch-type", "rethrow");
297 uiout
->field_string ("what", "exception catch");
298 if (uiout
->is_mi_like_p ())
299 uiout
->field_string ("catch-type", "catch");
304 /* Implement the 'print_one_detail' method. */
307 print_one_detail_exception_catchpoint (const struct breakpoint
*b
,
308 struct ui_out
*uiout
)
310 const struct exception_catchpoint
*cp
311 = (const struct exception_catchpoint
*) b
;
313 if (!cp
->exception_rx
.empty ())
315 uiout
->text (_("\tmatching: "));
316 uiout
->field_string ("regexp", cp
->exception_rx
.c_str ());
322 print_mention_exception_catchpoint (struct breakpoint
*b
)
324 struct ui_out
*uiout
= current_uiout
;
326 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
328 bp_temp
= b
->disposition
== disp_del
;
329 uiout
->text (bp_temp
? _("Temporary catchpoint ")
331 uiout
->field_int ("bkptno", b
->number
);
332 uiout
->text ((kind
== EX_EVENT_THROW
? _(" (throw)")
333 : (kind
== EX_EVENT_CATCH
? _(" (catch)")
334 : _(" (rethrow)"))));
337 /* Implement the "print_recreate" breakpoint_ops method for throw and
338 catch catchpoints. */
341 print_recreate_exception_catchpoint (struct breakpoint
*b
,
345 enum exception_event_kind kind
= classify_exception_breakpoint (b
);
347 bp_temp
= b
->disposition
== disp_del
;
348 fprintf_unfiltered (fp
, bp_temp
? "tcatch " : "catch ");
352 fprintf_unfiltered (fp
, "throw");
355 fprintf_unfiltered (fp
, "catch");
357 case EX_EVENT_RETHROW
:
358 fprintf_unfiltered (fp
, "rethrow");
361 print_recreate_thread (b
, fp
);
365 handle_gnu_v3_exceptions (int tempflag
, std::string
&&except_rx
,
366 const char *cond_string
,
367 enum exception_event_kind ex_event
, int from_tty
)
369 std::unique_ptr
<compiled_regex
> pattern
;
371 if (!except_rx
.empty ())
373 pattern
.reset (new compiled_regex (except_rx
.c_str (), REG_NOSUB
,
374 _("invalid type-matching regexp")));
377 std::unique_ptr
<exception_catchpoint
> cp (new exception_catchpoint ());
379 init_catchpoint (cp
.get (), get_current_arch (), tempflag
, cond_string
,
380 &gnu_v3_exception_catchpoint_ops
);
381 /* We need to reset 'type' in order for code in breakpoint.c to do
383 cp
->type
= bp_breakpoint
;
385 cp
->exception_rx
= except_rx
;
386 cp
->pattern
= std::move (pattern
);
388 re_set_exception_catchpoint (cp
.get ());
390 install_breakpoint (0, cp
.get (), 1);
394 /* Look for an "if" token in *STRING. The "if" token must be preceded
397 If there is any non-whitespace text between *STRING and the "if"
398 token, then it is returned in a newly-xmalloc'd string. Otherwise,
401 STRING is updated to point to the "if" token, if it exists, or to
402 the end of the string. */
405 extract_exception_regexp (const char **string
)
408 const char *last
, *last_space
;
410 start
= skip_spaces_const (*string
);
414 while (*last
!= '\0')
416 const char *if_token
= last
;
418 /* Check for the "if". */
419 if (check_for_argument (&if_token
, "if", 2))
422 /* No "if" token here. Skip to the next word start. */
423 last_space
= skip_to_space (last
);
424 last
= skip_spaces_const (last_space
);
428 if (last_space
> start
)
429 return std::string (start
, last_space
- start
);
430 return std::string ();
433 /* Deal with "catch catch", "catch throw", and "catch rethrow"
437 catch_exception_command_1 (enum exception_event_kind ex_event
,
439 int tempflag
, int from_tty
)
441 const char *cond_string
= NULL
;
442 const char *arg
= arg_entry
;
446 arg
= skip_spaces_const (arg
);
448 std::string except_rx
= extract_exception_regexp (&arg
);
450 cond_string
= ep_parse_optional_if_clause (&arg
);
452 if ((*arg
!= '\0') && !isspace (*arg
))
453 error (_("Junk at end of arguments."));
455 if (ex_event
!= EX_EVENT_THROW
456 && ex_event
!= EX_EVENT_CATCH
457 && ex_event
!= EX_EVENT_RETHROW
)
458 error (_("Unsupported or unknown exception event; cannot catch it"));
460 handle_gnu_v3_exceptions (tempflag
, std::move (except_rx
), cond_string
,
464 /* Implementation of "catch catch" command. */
467 catch_catch_command (char *arg
, int from_tty
, struct cmd_list_element
*command
)
469 int tempflag
= get_cmd_context (command
) == CATCH_TEMPORARY
;
471 catch_exception_command_1 (EX_EVENT_CATCH
, arg
, tempflag
, from_tty
);
474 /* Implementation of "catch throw" command. */
477 catch_throw_command (char *arg
, int from_tty
, struct cmd_list_element
*command
)
479 int tempflag
= get_cmd_context (command
) == CATCH_TEMPORARY
;
481 catch_exception_command_1 (EX_EVENT_THROW
, arg
, tempflag
, from_tty
);
484 /* Implementation of "catch rethrow" command. */
487 catch_rethrow_command (char *arg
, int from_tty
,
488 struct cmd_list_element
*command
)
490 int tempflag
= get_cmd_context (command
) == CATCH_TEMPORARY
;
492 catch_exception_command_1 (EX_EVENT_RETHROW
, arg
, tempflag
, from_tty
);
497 /* Implement the 'make_value' method for the $_exception
500 static struct value
*
501 compute_exception (struct gdbarch
*argc
, struct internalvar
*var
, void *ignore
)
503 struct value
*arg0
, *arg1
;
504 struct type
*obj_type
;
506 fetch_probe_arguments (&arg0
, &arg1
);
508 /* ARG0 is a pointer to the exception object. ARG1 is a pointer to
509 the std::type_info for the exception. Now we find the type from
510 the type_info and cast the result. */
511 obj_type
= cplus_type_from_type_info (arg1
);
512 return value_ind (value_cast (make_pointer_type (obj_type
, NULL
), arg0
));
515 /* Implementation of the '$_exception' variable. */
517 static const struct internalvar_funcs exception_funcs
=
527 initialize_throw_catchpoint_ops (void)
529 struct breakpoint_ops
*ops
;
531 initialize_breakpoint_ops ();
533 /* GNU v3 exception catchpoints. */
534 ops
= &gnu_v3_exception_catchpoint_ops
;
535 *ops
= bkpt_breakpoint_ops
;
536 ops
->re_set
= re_set_exception_catchpoint
;
537 ops
->print_it
= print_it_exception_catchpoint
;
538 ops
->print_one
= print_one_exception_catchpoint
;
539 ops
->print_mention
= print_mention_exception_catchpoint
;
540 ops
->print_recreate
= print_recreate_exception_catchpoint
;
541 ops
->print_one_detail
= print_one_detail_exception_catchpoint
;
542 ops
->check_status
= check_status_exception_catchpoint
;
545 initialize_file_ftype _initialize_break_catch_throw
;
548 _initialize_break_catch_throw (void)
550 initialize_throw_catchpoint_ops ();
552 /* Add catch and tcatch sub-commands. */
553 add_catch_command ("catch", _("\
554 Catch an exception, when caught."),
559 add_catch_command ("throw", _("\
560 Catch an exception, when thrown."),
565 add_catch_command ("rethrow", _("\
566 Catch an exception, when rethrown."),
567 catch_rethrow_command
,
572 create_internalvar_type_lazy ("_exception", &exception_funcs
, NULL
);