| 1 | /* Everything about catch/throw catchpoints, for GDB. |
| 2 | |
| 3 | Copyright (C) 1986-2017 Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of GDB. |
| 6 | |
| 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. |
| 11 | |
| 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. |
| 16 | |
| 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/>. */ |
| 19 | |
| 20 | #include "defs.h" |
| 21 | #include "arch-utils.h" |
| 22 | #include <ctype.h> |
| 23 | #include "breakpoint.h" |
| 24 | #include "gdbcmd.h" |
| 25 | #include "inferior.h" |
| 26 | #include "annotate.h" |
| 27 | #include "valprint.h" |
| 28 | #include "cli/cli-utils.h" |
| 29 | #include "completer.h" |
| 30 | #include "gdb_obstack.h" |
| 31 | #include "mi/mi-common.h" |
| 32 | #include "linespec.h" |
| 33 | #include "probe.h" |
| 34 | #include "objfiles.h" |
| 35 | #include "cp-abi.h" |
| 36 | #include "gdb_regex.h" |
| 37 | #include "cp-support.h" |
| 38 | #include "location.h" |
| 39 | |
| 40 | /* Enums for exception-handling support. */ |
| 41 | enum exception_event_kind |
| 42 | { |
| 43 | EX_EVENT_THROW, |
| 44 | EX_EVENT_RETHROW, |
| 45 | EX_EVENT_CATCH |
| 46 | }; |
| 47 | |
| 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. */ |
| 51 | |
| 52 | struct exception_names |
| 53 | { |
| 54 | /* The name of the probe point to try, in the form accepted by |
| 55 | 'parse_probes'. */ |
| 56 | |
| 57 | const char *probe; |
| 58 | |
| 59 | /* The name of the corresponding function. */ |
| 60 | |
| 61 | const char *function; |
| 62 | }; |
| 63 | |
| 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[] = |
| 67 | { |
| 68 | { "-probe-stap libstdcxx:throw", "__cxa_throw" }, |
| 69 | { "-probe-stap libstdcxx:rethrow", "__cxa_rethrow" }, |
| 70 | { "-probe-stap libstdcxx:catch", "__cxa_begin_catch" } |
| 71 | }; |
| 72 | |
| 73 | static struct breakpoint_ops gnu_v3_exception_catchpoint_ops; |
| 74 | |
| 75 | /* The type of an exception catchpoint. */ |
| 76 | |
| 77 | struct exception_catchpoint : public breakpoint |
| 78 | { |
| 79 | /* The kind of exception catchpoint. */ |
| 80 | |
| 81 | enum exception_event_kind kind; |
| 82 | |
| 83 | /* If not empty, a string holding the source form of the regular |
| 84 | expression to match against. */ |
| 85 | |
| 86 | std::string exception_rx; |
| 87 | |
| 88 | /* If non-NULL, a compiled regular expression which is used to |
| 89 | determine which exceptions to stop on. */ |
| 90 | |
| 91 | std::unique_ptr<compiled_regex> pattern; |
| 92 | }; |
| 93 | |
| 94 | \f |
| 95 | |
| 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. */ |
| 99 | |
| 100 | static void |
| 101 | fetch_probe_arguments (struct value **arg0, struct value **arg1) |
| 102 | { |
| 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; |
| 106 | unsigned n_args; |
| 107 | |
| 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")); |
| 115 | |
| 116 | n_args = get_probe_argument_count (pc_probe.probe, frame); |
| 117 | if (n_args < 2) |
| 118 | error (_("C++ exception catchpoint has too few arguments")); |
| 119 | |
| 120 | if (arg0 != NULL) |
| 121 | *arg0 = evaluate_probe_argument (pc_probe.probe, 0, frame); |
| 122 | *arg1 = evaluate_probe_argument (pc_probe.probe, 1, frame); |
| 123 | |
| 124 | if ((arg0 != NULL && *arg0 == NULL) || *arg1 == NULL) |
| 125 | error (_("error computing probe argument at c++ exception catchpoint")); |
| 126 | } |
| 127 | |
| 128 | \f |
| 129 | |
| 130 | /* A helper function that returns a value indicating the kind of the |
| 131 | exception catchpoint B. */ |
| 132 | |
| 133 | static enum exception_event_kind |
| 134 | classify_exception_breakpoint (struct breakpoint *b) |
| 135 | { |
| 136 | struct exception_catchpoint *cp = (struct exception_catchpoint *) b; |
| 137 | |
| 138 | return cp->kind; |
| 139 | } |
| 140 | |
| 141 | /* Implement the 'check_status' method. */ |
| 142 | |
| 143 | static void |
| 144 | check_status_exception_catchpoint (struct bpstats *bs) |
| 145 | { |
| 146 | struct exception_catchpoint *self |
| 147 | = (struct exception_catchpoint *) bs->breakpoint_at; |
| 148 | std::string type_name; |
| 149 | |
| 150 | bkpt_breakpoint_ops.check_status (bs); |
| 151 | if (bs->stop == 0) |
| 152 | return; |
| 153 | |
| 154 | if (self->pattern == NULL) |
| 155 | return; |
| 156 | |
| 157 | TRY |
| 158 | { |
| 159 | struct value *typeinfo_arg; |
| 160 | std::string canon; |
| 161 | |
| 162 | fetch_probe_arguments (NULL, &typeinfo_arg); |
| 163 | type_name = cplus_typename_from_type_info (typeinfo_arg); |
| 164 | |
| 165 | canon = cp_canonicalize_string (type_name.c_str ()); |
| 166 | if (!canon.empty ()) |
| 167 | std::swap (type_name, canon); |
| 168 | } |
| 169 | CATCH (e, RETURN_MASK_ERROR) |
| 170 | { |
| 171 | exception_print (gdb_stderr, e); |
| 172 | } |
| 173 | END_CATCH |
| 174 | |
| 175 | if (!type_name.empty ()) |
| 176 | { |
| 177 | if (self->pattern->exec (type_name.c_str (), 0, NULL, 0) != 0) |
| 178 | bs->stop = 0; |
| 179 | } |
| 180 | } |
| 181 | |
| 182 | /* Implement the 're_set' method. */ |
| 183 | |
| 184 | static void |
| 185 | re_set_exception_catchpoint (struct breakpoint *self) |
| 186 | { |
| 187 | std::vector<symtab_and_line> sals; |
| 188 | enum exception_event_kind kind = classify_exception_breakpoint (self); |
| 189 | struct program_space *filter_pspace = current_program_space; |
| 190 | |
| 191 | /* We first try to use the probe interface. */ |
| 192 | TRY |
| 193 | { |
| 194 | event_location_up location |
| 195 | = new_probe_location (exception_functions[kind].probe); |
| 196 | sals = parse_probes (location.get (), filter_pspace, NULL); |
| 197 | } |
| 198 | CATCH (e, RETURN_MASK_ERROR) |
| 199 | { |
| 200 | /* Using the probe interface failed. Let's fallback to the normal |
| 201 | catchpoint mode. */ |
| 202 | TRY |
| 203 | { |
| 204 | struct explicit_location explicit_loc; |
| 205 | |
| 206 | initialize_explicit_location (&explicit_loc); |
| 207 | explicit_loc.function_name |
| 208 | = ASTRDUP (exception_functions[kind].function); |
| 209 | event_location_up location = new_explicit_location (&explicit_loc); |
| 210 | sals = self->ops->decode_location (self, location.get (), |
| 211 | filter_pspace); |
| 212 | } |
| 213 | CATCH (ex, RETURN_MASK_ERROR) |
| 214 | { |
| 215 | /* NOT_FOUND_ERROR just means the breakpoint will be |
| 216 | pending, so let it through. */ |
| 217 | if (ex.error != NOT_FOUND_ERROR) |
| 218 | throw_exception (ex); |
| 219 | } |
| 220 | END_CATCH |
| 221 | } |
| 222 | END_CATCH |
| 223 | |
| 224 | update_breakpoint_locations (self, filter_pspace, sals, {}); |
| 225 | } |
| 226 | |
| 227 | static enum print_stop_action |
| 228 | print_it_exception_catchpoint (bpstat bs) |
| 229 | { |
| 230 | struct ui_out *uiout = current_uiout; |
| 231 | struct breakpoint *b = bs->breakpoint_at; |
| 232 | int bp_temp; |
| 233 | enum exception_event_kind kind = classify_exception_breakpoint (b); |
| 234 | |
| 235 | annotate_catchpoint (b->number); |
| 236 | maybe_print_thread_hit_breakpoint (uiout); |
| 237 | |
| 238 | bp_temp = b->disposition == disp_del; |
| 239 | uiout->text (bp_temp ? "Temporary catchpoint " |
| 240 | : "Catchpoint "); |
| 241 | if (!uiout->is_mi_like_p ()) |
| 242 | uiout->field_int ("bkptno", b->number); |
| 243 | uiout->text ((kind == EX_EVENT_THROW ? " (exception thrown), " |
| 244 | : (kind == EX_EVENT_CATCH ? " (exception caught), " |
| 245 | : " (exception rethrown), "))); |
| 246 | if (uiout->is_mi_like_p ()) |
| 247 | { |
| 248 | uiout->field_string ("reason", |
| 249 | async_reason_lookup (EXEC_ASYNC_BREAKPOINT_HIT)); |
| 250 | uiout->field_string ("disp", bpdisp_text (b->disposition)); |
| 251 | uiout->field_int ("bkptno", b->number); |
| 252 | } |
| 253 | return PRINT_SRC_AND_LOC; |
| 254 | } |
| 255 | |
| 256 | static void |
| 257 | print_one_exception_catchpoint (struct breakpoint *b, |
| 258 | struct bp_location **last_loc) |
| 259 | { |
| 260 | struct value_print_options opts; |
| 261 | struct ui_out *uiout = current_uiout; |
| 262 | enum exception_event_kind kind = classify_exception_breakpoint (b); |
| 263 | |
| 264 | get_user_print_options (&opts); |
| 265 | if (opts.addressprint) |
| 266 | { |
| 267 | annotate_field (4); |
| 268 | if (b->loc == NULL || b->loc->shlib_disabled) |
| 269 | uiout->field_string ("addr", "<PENDING>"); |
| 270 | else |
| 271 | uiout->field_core_addr ("addr", |
| 272 | b->loc->gdbarch, b->loc->address); |
| 273 | } |
| 274 | annotate_field (5); |
| 275 | if (b->loc) |
| 276 | *last_loc = b->loc; |
| 277 | |
| 278 | switch (kind) |
| 279 | { |
| 280 | case EX_EVENT_THROW: |
| 281 | uiout->field_string ("what", "exception throw"); |
| 282 | if (uiout->is_mi_like_p ()) |
| 283 | uiout->field_string ("catch-type", "throw"); |
| 284 | break; |
| 285 | |
| 286 | case EX_EVENT_RETHROW: |
| 287 | uiout->field_string ("what", "exception rethrow"); |
| 288 | if (uiout->is_mi_like_p ()) |
| 289 | uiout->field_string ("catch-type", "rethrow"); |
| 290 | break; |
| 291 | |
| 292 | case EX_EVENT_CATCH: |
| 293 | uiout->field_string ("what", "exception catch"); |
| 294 | if (uiout->is_mi_like_p ()) |
| 295 | uiout->field_string ("catch-type", "catch"); |
| 296 | break; |
| 297 | } |
| 298 | } |
| 299 | |
| 300 | /* Implement the 'print_one_detail' method. */ |
| 301 | |
| 302 | static void |
| 303 | print_one_detail_exception_catchpoint (const struct breakpoint *b, |
| 304 | struct ui_out *uiout) |
| 305 | { |
| 306 | const struct exception_catchpoint *cp |
| 307 | = (const struct exception_catchpoint *) b; |
| 308 | |
| 309 | if (!cp->exception_rx.empty ()) |
| 310 | { |
| 311 | uiout->text (_("\tmatching: ")); |
| 312 | uiout->field_string ("regexp", cp->exception_rx.c_str ()); |
| 313 | uiout->text ("\n"); |
| 314 | } |
| 315 | } |
| 316 | |
| 317 | static void |
| 318 | print_mention_exception_catchpoint (struct breakpoint *b) |
| 319 | { |
| 320 | struct ui_out *uiout = current_uiout; |
| 321 | int bp_temp; |
| 322 | enum exception_event_kind kind = classify_exception_breakpoint (b); |
| 323 | |
| 324 | bp_temp = b->disposition == disp_del; |
| 325 | uiout->text (bp_temp ? _("Temporary catchpoint ") |
| 326 | : _("Catchpoint ")); |
| 327 | uiout->field_int ("bkptno", b->number); |
| 328 | uiout->text ((kind == EX_EVENT_THROW ? _(" (throw)") |
| 329 | : (kind == EX_EVENT_CATCH ? _(" (catch)") |
| 330 | : _(" (rethrow)")))); |
| 331 | } |
| 332 | |
| 333 | /* Implement the "print_recreate" breakpoint_ops method for throw and |
| 334 | catch catchpoints. */ |
| 335 | |
| 336 | static void |
| 337 | print_recreate_exception_catchpoint (struct breakpoint *b, |
| 338 | struct ui_file *fp) |
| 339 | { |
| 340 | int bp_temp; |
| 341 | enum exception_event_kind kind = classify_exception_breakpoint (b); |
| 342 | |
| 343 | bp_temp = b->disposition == disp_del; |
| 344 | fprintf_unfiltered (fp, bp_temp ? "tcatch " : "catch "); |
| 345 | switch (kind) |
| 346 | { |
| 347 | case EX_EVENT_THROW: |
| 348 | fprintf_unfiltered (fp, "throw"); |
| 349 | break; |
| 350 | case EX_EVENT_CATCH: |
| 351 | fprintf_unfiltered (fp, "catch"); |
| 352 | break; |
| 353 | case EX_EVENT_RETHROW: |
| 354 | fprintf_unfiltered (fp, "rethrow"); |
| 355 | break; |
| 356 | } |
| 357 | print_recreate_thread (b, fp); |
| 358 | } |
| 359 | |
| 360 | static void |
| 361 | handle_gnu_v3_exceptions (int tempflag, std::string &&except_rx, |
| 362 | const char *cond_string, |
| 363 | enum exception_event_kind ex_event, int from_tty) |
| 364 | { |
| 365 | std::unique_ptr<compiled_regex> pattern; |
| 366 | |
| 367 | if (!except_rx.empty ()) |
| 368 | { |
| 369 | pattern.reset (new compiled_regex (except_rx.c_str (), REG_NOSUB, |
| 370 | _("invalid type-matching regexp"))); |
| 371 | } |
| 372 | |
| 373 | std::unique_ptr<exception_catchpoint> cp (new exception_catchpoint ()); |
| 374 | |
| 375 | init_catchpoint (cp.get (), get_current_arch (), tempflag, cond_string, |
| 376 | &gnu_v3_exception_catchpoint_ops); |
| 377 | /* We need to reset 'type' in order for code in breakpoint.c to do |
| 378 | the right thing. */ |
| 379 | cp->type = bp_breakpoint; |
| 380 | cp->kind = ex_event; |
| 381 | cp->exception_rx = std::move (except_rx); |
| 382 | cp->pattern = std::move (pattern); |
| 383 | |
| 384 | re_set_exception_catchpoint (cp.get ()); |
| 385 | |
| 386 | install_breakpoint (0, std::move (cp), 1); |
| 387 | } |
| 388 | |
| 389 | /* Look for an "if" token in *STRING. The "if" token must be preceded |
| 390 | by whitespace. |
| 391 | |
| 392 | If there is any non-whitespace text between *STRING and the "if" |
| 393 | token, then it is returned in a newly-xmalloc'd string. Otherwise, |
| 394 | this returns NULL. |
| 395 | |
| 396 | STRING is updated to point to the "if" token, if it exists, or to |
| 397 | the end of the string. */ |
| 398 | |
| 399 | static std::string |
| 400 | extract_exception_regexp (const char **string) |
| 401 | { |
| 402 | const char *start; |
| 403 | const char *last, *last_space; |
| 404 | |
| 405 | start = skip_spaces_const (*string); |
| 406 | |
| 407 | last = start; |
| 408 | last_space = start; |
| 409 | while (*last != '\0') |
| 410 | { |
| 411 | const char *if_token = last; |
| 412 | |
| 413 | /* Check for the "if". */ |
| 414 | if (check_for_argument (&if_token, "if", 2)) |
| 415 | break; |
| 416 | |
| 417 | /* No "if" token here. Skip to the next word start. */ |
| 418 | last_space = skip_to_space (last); |
| 419 | last = skip_spaces_const (last_space); |
| 420 | } |
| 421 | |
| 422 | *string = last; |
| 423 | if (last_space > start) |
| 424 | return std::string (start, last_space - start); |
| 425 | return std::string (); |
| 426 | } |
| 427 | |
| 428 | /* Deal with "catch catch", "catch throw", and "catch rethrow" |
| 429 | commands. */ |
| 430 | |
| 431 | static void |
| 432 | catch_exception_command_1 (enum exception_event_kind ex_event, |
| 433 | char *arg_entry, |
| 434 | int tempflag, int from_tty) |
| 435 | { |
| 436 | const char *cond_string = NULL; |
| 437 | const char *arg = arg_entry; |
| 438 | |
| 439 | if (!arg) |
| 440 | arg = ""; |
| 441 | arg = skip_spaces_const (arg); |
| 442 | |
| 443 | std::string except_rx = extract_exception_regexp (&arg); |
| 444 | |
| 445 | cond_string = ep_parse_optional_if_clause (&arg); |
| 446 | |
| 447 | if ((*arg != '\0') && !isspace (*arg)) |
| 448 | error (_("Junk at end of arguments.")); |
| 449 | |
| 450 | if (ex_event != EX_EVENT_THROW |
| 451 | && ex_event != EX_EVENT_CATCH |
| 452 | && ex_event != EX_EVENT_RETHROW) |
| 453 | error (_("Unsupported or unknown exception event; cannot catch it")); |
| 454 | |
| 455 | handle_gnu_v3_exceptions (tempflag, std::move (except_rx), cond_string, |
| 456 | ex_event, from_tty); |
| 457 | } |
| 458 | |
| 459 | /* Implementation of "catch catch" command. */ |
| 460 | |
| 461 | static void |
| 462 | catch_catch_command (char *arg, int from_tty, struct cmd_list_element *command) |
| 463 | { |
| 464 | int tempflag = get_cmd_context (command) == CATCH_TEMPORARY; |
| 465 | |
| 466 | catch_exception_command_1 (EX_EVENT_CATCH, arg, tempflag, from_tty); |
| 467 | } |
| 468 | |
| 469 | /* Implementation of "catch throw" command. */ |
| 470 | |
| 471 | static void |
| 472 | catch_throw_command (char *arg, int from_tty, struct cmd_list_element *command) |
| 473 | { |
| 474 | int tempflag = get_cmd_context (command) == CATCH_TEMPORARY; |
| 475 | |
| 476 | catch_exception_command_1 (EX_EVENT_THROW, arg, tempflag, from_tty); |
| 477 | } |
| 478 | |
| 479 | /* Implementation of "catch rethrow" command. */ |
| 480 | |
| 481 | static void |
| 482 | catch_rethrow_command (char *arg, int from_tty, |
| 483 | struct cmd_list_element *command) |
| 484 | { |
| 485 | int tempflag = get_cmd_context (command) == CATCH_TEMPORARY; |
| 486 | |
| 487 | catch_exception_command_1 (EX_EVENT_RETHROW, arg, tempflag, from_tty); |
| 488 | } |
| 489 | |
| 490 | \f |
| 491 | |
| 492 | /* Implement the 'make_value' method for the $_exception |
| 493 | internalvar. */ |
| 494 | |
| 495 | static struct value * |
| 496 | compute_exception (struct gdbarch *argc, struct internalvar *var, void *ignore) |
| 497 | { |
| 498 | struct value *arg0, *arg1; |
| 499 | struct type *obj_type; |
| 500 | |
| 501 | fetch_probe_arguments (&arg0, &arg1); |
| 502 | |
| 503 | /* ARG0 is a pointer to the exception object. ARG1 is a pointer to |
| 504 | the std::type_info for the exception. Now we find the type from |
| 505 | the type_info and cast the result. */ |
| 506 | obj_type = cplus_type_from_type_info (arg1); |
| 507 | return value_ind (value_cast (make_pointer_type (obj_type, NULL), arg0)); |
| 508 | } |
| 509 | |
| 510 | /* Implementation of the '$_exception' variable. */ |
| 511 | |
| 512 | static const struct internalvar_funcs exception_funcs = |
| 513 | { |
| 514 | compute_exception, |
| 515 | NULL, |
| 516 | NULL |
| 517 | }; |
| 518 | |
| 519 | \f |
| 520 | |
| 521 | static void |
| 522 | initialize_throw_catchpoint_ops (void) |
| 523 | { |
| 524 | struct breakpoint_ops *ops; |
| 525 | |
| 526 | initialize_breakpoint_ops (); |
| 527 | |
| 528 | /* GNU v3 exception catchpoints. */ |
| 529 | ops = &gnu_v3_exception_catchpoint_ops; |
| 530 | *ops = bkpt_breakpoint_ops; |
| 531 | ops->re_set = re_set_exception_catchpoint; |
| 532 | ops->print_it = print_it_exception_catchpoint; |
| 533 | ops->print_one = print_one_exception_catchpoint; |
| 534 | ops->print_mention = print_mention_exception_catchpoint; |
| 535 | ops->print_recreate = print_recreate_exception_catchpoint; |
| 536 | ops->print_one_detail = print_one_detail_exception_catchpoint; |
| 537 | ops->check_status = check_status_exception_catchpoint; |
| 538 | } |
| 539 | |
| 540 | initialize_file_ftype _initialize_break_catch_throw; |
| 541 | |
| 542 | void |
| 543 | _initialize_break_catch_throw (void) |
| 544 | { |
| 545 | initialize_throw_catchpoint_ops (); |
| 546 | |
| 547 | /* Add catch and tcatch sub-commands. */ |
| 548 | add_catch_command ("catch", _("\ |
| 549 | Catch an exception, when caught."), |
| 550 | catch_catch_command, |
| 551 | NULL, |
| 552 | CATCH_PERMANENT, |
| 553 | CATCH_TEMPORARY); |
| 554 | add_catch_command ("throw", _("\ |
| 555 | Catch an exception, when thrown."), |
| 556 | catch_throw_command, |
| 557 | NULL, |
| 558 | CATCH_PERMANENT, |
| 559 | CATCH_TEMPORARY); |
| 560 | add_catch_command ("rethrow", _("\ |
| 561 | Catch an exception, when rethrown."), |
| 562 | catch_rethrow_command, |
| 563 | NULL, |
| 564 | CATCH_PERMANENT, |
| 565 | CATCH_TEMPORARY); |
| 566 | |
| 567 | create_internalvar_type_lazy ("_exception", &exception_funcs, NULL); |
| 568 | } |