| /* Everything about catch/throw catchpoints, for GDB. |
| |
| Copyright (C) 1986-2021 Free Software Foundation, Inc. |
| |
| This file is part of GDB. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| |
| #include "defs.h" |
| #include "arch-utils.h" |
| #include <ctype.h> |
| #include "breakpoint.h" |
| #include "gdbcmd.h" |
| #include "inferior.h" |
| #include "annotate.h" |
| #include "valprint.h" |
| #include "cli/cli-utils.h" |
| #include "completer.h" |
| #include "gdb_obstack.h" |
| #include "mi/mi-common.h" |
| #include "linespec.h" |
| #include "probe.h" |
| #include "objfiles.h" |
| #include "cp-abi.h" |
| #include "gdb_regex.h" |
| #include "cp-support.h" |
| #include "location.h" |
| #include "cli/cli-decode.h" |
| |
| /* Each spot where we may place an exception-related catchpoint has |
| two names: the SDT probe point and the function name. This |
| structure holds both. */ |
| |
| struct exception_names |
| { |
| /* The name of the probe point to try, in the form accepted by |
| 'parse_probes'. */ |
| |
| const char *probe; |
| |
| /* The name of the corresponding function. */ |
| |
| const char *function; |
| }; |
| |
| /* Names of the probe points and functions on which to break. This is |
| indexed by exception_event_kind. */ |
| static const struct exception_names exception_functions[] = |
| { |
| { "-probe-stap libstdcxx:throw", "__cxa_throw" }, |
| { "-probe-stap libstdcxx:rethrow", "__cxa_rethrow" }, |
| { "-probe-stap libstdcxx:catch", "__cxa_begin_catch" } |
| }; |
| |
| static struct breakpoint_ops gnu_v3_exception_catchpoint_ops; |
| |
| /* The type of an exception catchpoint. */ |
| |
| struct exception_catchpoint : public breakpoint |
| { |
| /* The kind of exception catchpoint. */ |
| |
| enum exception_event_kind kind; |
| |
| /* If not empty, a string holding the source form of the regular |
| expression to match against. */ |
| |
| std::string exception_rx; |
| |
| /* If non-NULL, a compiled regular expression which is used to |
| determine which exceptions to stop on. */ |
| |
| std::unique_ptr<compiled_regex> pattern; |
| }; |
| |
| /* See breakpoint.h. */ |
| |
| bool |
| is_exception_catchpoint (breakpoint *bp) |
| { |
| return bp->ops == &gnu_v3_exception_catchpoint_ops; |
| } |
| |
| |
| |
| /* A helper function that fetches exception probe arguments. This |
| fills in *ARG0 (if non-NULL) and *ARG1 (which must be non-NULL). |
| It will throw an exception on any kind of failure. */ |
| |
| static void |
| fetch_probe_arguments (struct value **arg0, struct value **arg1) |
| { |
| struct frame_info *frame = get_selected_frame (_("No frame selected")); |
| CORE_ADDR pc = get_frame_pc (frame); |
| struct bound_probe pc_probe; |
| unsigned n_args; |
| |
| pc_probe = find_probe_by_pc (pc); |
| if (pc_probe.prob == NULL) |
| error (_("did not find exception probe (does libstdcxx have SDT probes?)")); |
| |
| if (pc_probe.prob->get_provider () != "libstdcxx" |
| || (pc_probe.prob->get_name () != "catch" |
| && pc_probe.prob->get_name () != "throw" |
| && pc_probe.prob->get_name () != "rethrow")) |
| error (_("not stopped at a C++ exception catchpoint")); |
| |
| n_args = pc_probe.prob->get_argument_count (get_frame_arch (frame)); |
| if (n_args < 2) |
| error (_("C++ exception catchpoint has too few arguments")); |
| |
| if (arg0 != NULL) |
| *arg0 = pc_probe.prob->evaluate_argument (0, frame); |
| *arg1 = pc_probe.prob->evaluate_argument (1, frame); |
| |
| if ((arg0 != NULL && *arg0 == NULL) || *arg1 == NULL) |
| error (_("error computing probe argument at c++ exception catchpoint")); |
| } |
| |
| |
| |
| /* A helper function that returns a value indicating the kind of the |
| exception catchpoint B. */ |
| |
| static enum exception_event_kind |
| classify_exception_breakpoint (struct breakpoint *b) |
| { |
| struct exception_catchpoint *cp = (struct exception_catchpoint *) b; |
| |
| return cp->kind; |
| } |
| |
| /* Implement the 'check_status' method. */ |
| |
| static void |
| check_status_exception_catchpoint (struct bpstats *bs) |
| { |
| struct exception_catchpoint *self |
| = (struct exception_catchpoint *) bs->breakpoint_at; |
| std::string type_name; |
| |
| bkpt_breakpoint_ops.check_status (bs); |
| if (bs->stop == 0) |
| return; |
| |
| if (self->pattern == NULL) |
| return; |
| |
| const char *name = nullptr; |
| gdb::unique_xmalloc_ptr<char> canon; |
| try |
| { |
| struct value *typeinfo_arg; |
| |
| fetch_probe_arguments (NULL, &typeinfo_arg); |
| type_name = cplus_typename_from_type_info (typeinfo_arg); |
| |
| canon = cp_canonicalize_string (type_name.c_str ()); |
| name = (canon != nullptr |
| ? canon.get () |
| : type_name.c_str ()); |
| } |
| catch (const gdb_exception_error &e) |
| { |
| exception_print (gdb_stderr, e); |
| } |
| |
| if (name != nullptr) |
| { |
| if (self->pattern->exec (name, 0, NULL, 0) != 0) |
| bs->stop = 0; |
| } |
| } |
| |
| /* Implement the 're_set' method. */ |
| |
| static void |
| re_set_exception_catchpoint (struct breakpoint *self) |
| { |
| std::vector<symtab_and_line> sals; |
| enum exception_event_kind kind = classify_exception_breakpoint (self); |
| struct program_space *filter_pspace = current_program_space; |
| |
| /* We first try to use the probe interface. */ |
| try |
| { |
| event_location_up location |
| = new_probe_location (exception_functions[kind].probe); |
| sals = parse_probes (location.get (), filter_pspace, NULL); |
| } |
| catch (const gdb_exception_error &e) |
| { |
| /* Using the probe interface failed. Let's fallback to the normal |
| catchpoint mode. */ |
| try |
| { |
| struct explicit_location explicit_loc; |
| |
| initialize_explicit_location (&explicit_loc); |
| explicit_loc.function_name |
| = ASTRDUP (exception_functions[kind].function); |
| event_location_up location = new_explicit_location (&explicit_loc); |
| sals = self->ops->decode_location (self, location.get (), |
| filter_pspace); |
| } |
| catch (const gdb_exception_error &ex) |
| { |
| /* NOT_FOUND_ERROR just means the breakpoint will be |
| pending, so let it through. */ |
| if (ex.error != NOT_FOUND_ERROR) |
| throw; |
| } |
| } |
| |
| update_breakpoint_locations (self, filter_pspace, sals, {}); |
| } |
| |
| static enum print_stop_action |
| print_it_exception_catchpoint (bpstat bs) |
| { |
| struct ui_out *uiout = current_uiout; |
| struct breakpoint *b = bs->breakpoint_at; |
| int bp_temp; |
| enum exception_event_kind kind = classify_exception_breakpoint (b); |
| |
| annotate_catchpoint (b->number); |
| maybe_print_thread_hit_breakpoint (uiout); |
| |
| bp_temp = b->disposition == disp_del; |
| uiout->text (bp_temp ? "Temporary catchpoint " |
| : "Catchpoint "); |
| uiout->field_signed ("bkptno", b->number); |
| uiout->text ((kind == EX_EVENT_THROW ? " (exception thrown), " |
| : (kind == EX_EVENT_CATCH ? " (exception caught), " |
| : " (exception rethrown), "))); |
| if (uiout->is_mi_like_p ()) |
| { |
| uiout->field_string ("reason", |
| async_reason_lookup (EXEC_ASYNC_BREAKPOINT_HIT)); |
| uiout->field_string ("disp", bpdisp_text (b->disposition)); |
| } |
| return PRINT_SRC_AND_LOC; |
| } |
| |
| static void |
| print_one_exception_catchpoint (struct breakpoint *b, |
| struct bp_location **last_loc) |
| { |
| struct value_print_options opts; |
| struct ui_out *uiout = current_uiout; |
| enum exception_event_kind kind = classify_exception_breakpoint (b); |
| |
| get_user_print_options (&opts); |
| |
| if (opts.addressprint) |
| uiout->field_skip ("addr"); |
| annotate_field (5); |
| |
| switch (kind) |
| { |
| case EX_EVENT_THROW: |
| uiout->field_string ("what", "exception throw"); |
| if (uiout->is_mi_like_p ()) |
| uiout->field_string ("catch-type", "throw"); |
| break; |
| |
| case EX_EVENT_RETHROW: |
| uiout->field_string ("what", "exception rethrow"); |
| if (uiout->is_mi_like_p ()) |
| uiout->field_string ("catch-type", "rethrow"); |
| break; |
| |
| case EX_EVENT_CATCH: |
| uiout->field_string ("what", "exception catch"); |
| if (uiout->is_mi_like_p ()) |
| uiout->field_string ("catch-type", "catch"); |
| break; |
| } |
| } |
| |
| /* Implement the 'print_one_detail' method. */ |
| |
| static void |
| print_one_detail_exception_catchpoint (const struct breakpoint *b, |
| struct ui_out *uiout) |
| { |
| const struct exception_catchpoint *cp |
| = (const struct exception_catchpoint *) b; |
| |
| if (!cp->exception_rx.empty ()) |
| { |
| uiout->text (_("\tmatching: ")); |
| uiout->field_string ("regexp", cp->exception_rx); |
| uiout->text ("\n"); |
| } |
| } |
| |
| static void |
| print_mention_exception_catchpoint (struct breakpoint *b) |
| { |
| struct ui_out *uiout = current_uiout; |
| int bp_temp; |
| enum exception_event_kind kind = classify_exception_breakpoint (b); |
| |
| bp_temp = b->disposition == disp_del; |
| uiout->message ("%s %d %s", |
| (bp_temp ? _("Temporary catchpoint ") : _("Catchpoint")), |
| b->number, |
| (kind == EX_EVENT_THROW |
| ? _("(throw)") : (kind == EX_EVENT_CATCH |
| ? _("(catch)") : _("(rethrow)")))); |
| } |
| |
| /* Implement the "print_recreate" breakpoint_ops method for throw and |
| catch catchpoints. */ |
| |
| static void |
| print_recreate_exception_catchpoint (struct breakpoint *b, |
| struct ui_file *fp) |
| { |
| int bp_temp; |
| enum exception_event_kind kind = classify_exception_breakpoint (b); |
| |
| bp_temp = b->disposition == disp_del; |
| fprintf_unfiltered (fp, bp_temp ? "tcatch " : "catch "); |
| switch (kind) |
| { |
| case EX_EVENT_THROW: |
| fprintf_unfiltered (fp, "throw"); |
| break; |
| case EX_EVENT_CATCH: |
| fprintf_unfiltered (fp, "catch"); |
| break; |
| case EX_EVENT_RETHROW: |
| fprintf_unfiltered (fp, "rethrow"); |
| break; |
| } |
| print_recreate_thread (b, fp); |
| } |
| |
| /* Implement the "allocate_location" breakpoint_ops method for throw |
| and catch catchpoints. */ |
| |
| static bp_location * |
| allocate_location_exception_catchpoint (breakpoint *self) |
| { |
| return new bp_location (self, bp_loc_software_breakpoint); |
| } |
| |
| static void |
| handle_gnu_v3_exceptions (int tempflag, std::string &&except_rx, |
| const char *cond_string, |
| enum exception_event_kind ex_event, int from_tty) |
| { |
| std::unique_ptr<compiled_regex> pattern; |
| |
| if (!except_rx.empty ()) |
| { |
| pattern.reset (new compiled_regex (except_rx.c_str (), REG_NOSUB, |
| _("invalid type-matching regexp"))); |
| } |
| |
| std::unique_ptr<exception_catchpoint> cp (new exception_catchpoint ()); |
| |
| init_catchpoint (cp.get (), get_current_arch (), tempflag, cond_string, |
| &gnu_v3_exception_catchpoint_ops); |
| cp->kind = ex_event; |
| cp->exception_rx = std::move (except_rx); |
| cp->pattern = std::move (pattern); |
| |
| re_set_exception_catchpoint (cp.get ()); |
| |
| install_breakpoint (0, std::move (cp), 1); |
| } |
| |
| /* Look for an "if" token in *STRING. The "if" token must be preceded |
| by whitespace. |
| |
| If there is any non-whitespace text between *STRING and the "if" |
| token, then it is returned in a newly-xmalloc'd string. Otherwise, |
| this returns NULL. |
| |
| STRING is updated to point to the "if" token, if it exists, or to |
| the end of the string. */ |
| |
| static std::string |
| extract_exception_regexp (const char **string) |
| { |
| const char *start; |
| const char *last, *last_space; |
| |
| start = skip_spaces (*string); |
| |
| last = start; |
| last_space = start; |
| while (*last != '\0') |
| { |
| const char *if_token = last; |
| |
| /* Check for the "if". */ |
| if (check_for_argument (&if_token, "if", 2)) |
| break; |
| |
| /* No "if" token here. Skip to the next word start. */ |
| last_space = skip_to_space (last); |
| last = skip_spaces (last_space); |
| } |
| |
| *string = last; |
| if (last_space > start) |
| return std::string (start, last_space - start); |
| return std::string (); |
| } |
| |
| /* See breakpoint.h. */ |
| |
| void |
| catch_exception_event (enum exception_event_kind ex_event, |
| const char *arg, bool tempflag, int from_tty) |
| { |
| const char *cond_string = NULL; |
| |
| if (!arg) |
| arg = ""; |
| arg = skip_spaces (arg); |
| |
| std::string except_rx = extract_exception_regexp (&arg); |
| |
| cond_string = ep_parse_optional_if_clause (&arg); |
| |
| if ((*arg != '\0') && !isspace (*arg)) |
| error (_("Junk at end of arguments.")); |
| |
| if (ex_event != EX_EVENT_THROW |
| && ex_event != EX_EVENT_CATCH |
| && ex_event != EX_EVENT_RETHROW) |
| error (_("Unsupported or unknown exception event; cannot catch it")); |
| |
| handle_gnu_v3_exceptions (tempflag, std::move (except_rx), cond_string, |
| ex_event, from_tty); |
| } |
| |
| /* Implementation of "catch catch" command. */ |
| |
| static void |
| catch_catch_command (const char *arg, int from_tty, |
| struct cmd_list_element *command) |
| { |
| bool tempflag = command->context () == CATCH_TEMPORARY; |
| |
| catch_exception_event (EX_EVENT_CATCH, arg, tempflag, from_tty); |
| } |
| |
| /* Implementation of "catch throw" command. */ |
| |
| static void |
| catch_throw_command (const char *arg, int from_tty, |
| struct cmd_list_element *command) |
| { |
| bool tempflag = command->context () == CATCH_TEMPORARY; |
| |
| catch_exception_event (EX_EVENT_THROW, arg, tempflag, from_tty); |
| } |
| |
| /* Implementation of "catch rethrow" command. */ |
| |
| static void |
| catch_rethrow_command (const char *arg, int from_tty, |
| struct cmd_list_element *command) |
| { |
| bool tempflag = command->context () == CATCH_TEMPORARY; |
| |
| catch_exception_event (EX_EVENT_RETHROW, arg, tempflag, from_tty); |
| } |
| |
| |
| |
| /* Implement the 'make_value' method for the $_exception |
| internalvar. */ |
| |
| static struct value * |
| compute_exception (struct gdbarch *argc, struct internalvar *var, void *ignore) |
| { |
| struct value *arg0, *arg1; |
| struct type *obj_type; |
| |
| fetch_probe_arguments (&arg0, &arg1); |
| |
| /* ARG0 is a pointer to the exception object. ARG1 is a pointer to |
| the std::type_info for the exception. Now we find the type from |
| the type_info and cast the result. */ |
| obj_type = cplus_type_from_type_info (arg1); |
| return value_ind (value_cast (make_pointer_type (obj_type, NULL), arg0)); |
| } |
| |
| /* Implementation of the '$_exception' variable. */ |
| |
| static const struct internalvar_funcs exception_funcs = |
| { |
| compute_exception, |
| NULL, |
| NULL |
| }; |
| |
| |
| |
| static void |
| initialize_throw_catchpoint_ops (void) |
| { |
| struct breakpoint_ops *ops; |
| |
| initialize_breakpoint_ops (); |
| |
| /* GNU v3 exception catchpoints. */ |
| ops = &gnu_v3_exception_catchpoint_ops; |
| *ops = bkpt_breakpoint_ops; |
| ops->re_set = re_set_exception_catchpoint; |
| ops->print_it = print_it_exception_catchpoint; |
| ops->print_one = print_one_exception_catchpoint; |
| ops->print_mention = print_mention_exception_catchpoint; |
| ops->print_recreate = print_recreate_exception_catchpoint; |
| ops->print_one_detail = print_one_detail_exception_catchpoint; |
| ops->check_status = check_status_exception_catchpoint; |
| ops->allocate_location = allocate_location_exception_catchpoint; |
| } |
| |
| void _initialize_break_catch_throw (); |
| void |
| _initialize_break_catch_throw () |
| { |
| initialize_throw_catchpoint_ops (); |
| |
| /* Add catch and tcatch sub-commands. */ |
| add_catch_command ("catch", _("\ |
| Catch an exception, when caught."), |
| catch_catch_command, |
| NULL, |
| CATCH_PERMANENT, |
| CATCH_TEMPORARY); |
| add_catch_command ("throw", _("\ |
| Catch an exception, when thrown."), |
| catch_throw_command, |
| NULL, |
| CATCH_PERMANENT, |
| CATCH_TEMPORARY); |
| add_catch_command ("rethrow", _("\ |
| Catch an exception, when rethrown."), |
| catch_rethrow_command, |
| NULL, |
| CATCH_PERMANENT, |
| CATCH_TEMPORARY); |
| |
| create_internalvar_type_lazy ("_exception", &exception_funcs, NULL); |
| } |