gdb/break-catch-throw.c

   1 /* Everything about catch/throw catchpoints, for GDB.
   2
   3    Copyright (C) 1986-2013 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 "exceptions.h"
  33 #include "linespec.h"
  34 #include "probe.h"
  35
  36 /* Enums for exception-handling support.  */
  37 enum exception_event_kind
  38 {
  39   EX_EVENT_THROW,
  40   EX_EVENT_RETHROW,
  41   EX_EVENT_CATCH
  42 };
  43
  44 /* Each spot where we may place an exception-related catchpoint has
  45    two names: the SDT probe point and the function name.  This
  46    structure holds both.  */
  47
  48 struct exception_names
  49 {
  50   /* The name of the probe point to try, in the form accepted by
  51      'parse_probes'.  */
  52
  53   const char *probe;
  54
  55   /* The name of the corresponding function.  */
  56
  57   const char *function;
  58 };
  59
  60 /* Names of the probe points and functions on which to break.  This is
  61    indexed by exception_event_kind.  */
  62 static const struct exception_names exception_functions[] =
  63 {
  64   { "-probe-stap libstdcxx:throw", "__cxa_throw" },
  65   { "-probe-stap libstdcxx:rethrow", "__cxa_rethrow" },
  66   { "-probe-stap libstdcxx:catch", "__cxa_begin_catch" }
  67 };
  68
  69 static struct breakpoint_ops gnu_v3_exception_catchpoint_ops;
  70
  71 /* The type of an exception catchpoint.  */
  72
  73 struct exception_catchpoint
  74 {
  75   /* The base class.  */
  76
  77   struct breakpoint base;
  78
  79   /* The kind of exception catchpoint.  */
  80
  81   enum exception_event_kind kind;
  82 };
  83
  84 /* A helper function that returns a value indicating the kind of the
  85    exception catchpoint B.  */
  86
  87 static enum exception_event_kind
  88 classify_exception_breakpoint (struct breakpoint *b)
  89 {
  90   struct exception_catchpoint *cp = (struct exception_catchpoint *) b;
  91
  92   return cp->kind;
  93 }
  94
  95 /* Implement the 're_set' method.  */
  96
  97 static void
  98 re_set_exception_catchpoint (struct breakpoint *self)
  99 {
 100   struct symtabs_and_lines sals = {0};
 101   struct symtabs_and_lines sals_end = {0};
 102   volatile struct gdb_exception e;
 103   struct cleanup *cleanup;
 104   enum exception_event_kind kind = classify_exception_breakpoint (self);
 105   int pass;
 106
 107   for (pass = 0; sals.sals == NULL && pass < 2; ++pass)
 108     {
 109       TRY_CATCH (e, RETURN_MASK_ERROR)
 110         {
 111           char *spec;
 112
 113           if (pass == 0)
 114             {
 115               spec = ASTRDUP (exception_functions[kind].probe);
 116               sals = parse_probes (&spec, NULL);
 117             }
 118           else
 119             {
 120               spec = ASTRDUP (exception_functions[kind].function);
 121               self->ops->decode_linespec (self, &spec, &sals);
 122             }
 123         }
 124       /* NOT_FOUND_ERROR just means the breakpoint will be pending, so
 125          let it through.  */
 126       if (e.reason < 0 && e.error != NOT_FOUND_ERROR)
 127         throw_exception (e);
 128     }
 129
 130   cleanup = make_cleanup (xfree, sals.sals);
 131   update_breakpoint_locations (self, sals, sals_end);
 132   do_cleanups (cleanup);
 133 }
 134
 135 static enum print_stop_action
 136 print_it_exception_catchpoint (bpstat bs)
 137 {
 138   struct ui_out *uiout = current_uiout;
 139   struct breakpoint *b = bs->breakpoint_at;
 140   int bp_temp;
 141   enum exception_event_kind kind = classify_exception_breakpoint (b);
 142
 143   annotate_catchpoint (b->number);
 144
 145   bp_temp = b->disposition == disp_del;
 146   ui_out_text (uiout,
 147                bp_temp ? "Temporary catchpoint "
 148                        : "Catchpoint ");
 149   if (!ui_out_is_mi_like_p (uiout))
 150     ui_out_field_int (uiout, "bkptno", b->number);
 151   ui_out_text (uiout,
 152                (kind == EX_EVENT_THROW ? " (exception thrown), "
 153                 : (kind == EX_EVENT_CATCH ? " (exception caught), "
 154                    : " (exception rethrown), ")));
 155   if (ui_out_is_mi_like_p (uiout))
 156     {
 157       ui_out_field_string (uiout, "reason",
 158                            async_reason_lookup (EXEC_ASYNC_BREAKPOINT_HIT));
 159       ui_out_field_string (uiout, "disp", bpdisp_text (b->disposition));
 160       ui_out_field_int (uiout, "bkptno", b->number);
 161     }
 162   return PRINT_SRC_AND_LOC;
 163 }
 164
 165 static void
 166 print_one_exception_catchpoint (struct breakpoint *b,
 167                                 struct bp_location **last_loc)
 168 {
 169   struct value_print_options opts;
 170   struct ui_out *uiout = current_uiout;
 171   enum exception_event_kind kind = classify_exception_breakpoint (b);
 172
 173   get_user_print_options (&opts);
 174   if (opts.addressprint)
 175     {
 176       annotate_field (4);
 177       if (b->loc == NULL || b->loc->shlib_disabled)
 178         ui_out_field_string (uiout, "addr", "<PENDING>");
 179       else
 180         ui_out_field_core_addr (uiout, "addr",
 181                                 b->loc->gdbarch, b->loc->address);
 182     }
 183   annotate_field (5);
 184   if (b->loc)
 185     *last_loc = b->loc;
 186
 187   switch (kind)
 188     {
 189     case EX_EVENT_THROW:
 190       ui_out_field_string (uiout, "what", "exception throw");
 191       if (ui_out_is_mi_like_p (uiout))
 192         ui_out_field_string (uiout, "catch-type", "throw");
 193       break;
 194
 195     case EX_EVENT_RETHROW:
 196       ui_out_field_string (uiout, "what", "exception rethrow");
 197       if (ui_out_is_mi_like_p (uiout))
 198         ui_out_field_string (uiout, "catch-type", "rethrow");
 199       break;
 200
 201     case EX_EVENT_CATCH:
 202       ui_out_field_string (uiout, "what", "exception catch");
 203       if (ui_out_is_mi_like_p (uiout))
 204         ui_out_field_string (uiout, "catch-type", "catch");
 205       break;
 206     }
 207 }
 208
 209 static void
 210 print_mention_exception_catchpoint (struct breakpoint *b)
 211 {
 212   struct ui_out *uiout = current_uiout;
 213   int bp_temp;
 214   enum exception_event_kind kind = classify_exception_breakpoint (b);
 215
 216   bp_temp = b->disposition == disp_del;
 217   ui_out_text (uiout, bp_temp ? _("Temporary catchpoint ")
 218                               : _("Catchpoint "));
 219   ui_out_field_int (uiout, "bkptno", b->number);
 220   ui_out_text (uiout, (kind == EX_EVENT_THROW ? _(" (throw)")
 221                        : (kind == EX_EVENT_CATCH ? _(" (catch)")
 222                           : _(" (rethrow)"))));
 223 }
 224
 225 /* Implement the "print_recreate" breakpoint_ops method for throw and
 226    catch catchpoints.  */
 227
 228 static void
 229 print_recreate_exception_catchpoint (struct breakpoint *b,
 230                                      struct ui_file *fp)
 231 {
 232   int bp_temp;
 233   enum exception_event_kind kind = classify_exception_breakpoint (b);
 234
 235   bp_temp = b->disposition == disp_del;
 236   fprintf_unfiltered (fp, bp_temp ? "tcatch " : "catch ");
 237   switch (kind)
 238     {
 239     case EX_EVENT_THROW:
 240       fprintf_unfiltered (fp, "throw");
 241       break;
 242     case EX_EVENT_CATCH:
 243       fprintf_unfiltered (fp, "catch");
 244       break;
 245     case EX_EVENT_RETHROW:
 246       fprintf_unfiltered (fp, "rethrow");
 247       break;
 248     }
 249   print_recreate_thread (b, fp);
 250 }
 251
 252 static void
 253 handle_gnu_v3_exceptions (int tempflag, char *cond_string,
 254                           enum exception_event_kind ex_event, int from_tty)
 255 {
 256   struct exception_catchpoint *cp;
 257
 258   cp = XCNEW (struct exception_catchpoint);
 259   init_catchpoint (&cp->base, get_current_arch (), tempflag, cond_string,
 260                    &gnu_v3_exception_catchpoint_ops);
 261   /* We need to reset 'type' in order for code in breakpoint.c to do
 262      the right thing.  */
 263   cp->base.type = bp_breakpoint;
 264   cp->kind = ex_event;
 265
 266   re_set_exception_catchpoint (&cp->base);
 267
 268   install_breakpoint (0, &cp->base, 1);
 269 }
 270
 271 /* Deal with "catch catch", "catch throw", and "catch rethrow"
 272    commands.  */
 273
 274 static void
 275 catch_exception_command_1 (enum exception_event_kind ex_event, char *arg,
 276                            int tempflag, int from_tty)
 277 {
 278   char *cond_string = NULL;
 279
 280   if (!arg)
 281     arg = "";
 282   arg = skip_spaces (arg);
 283
 284   cond_string = ep_parse_optional_if_clause (&arg);
 285
 286   if ((*arg != '\0') && !isspace (*arg))
 287     error (_("Junk at end of arguments."));
 288
 289   if (ex_event != EX_EVENT_THROW
 290       && ex_event != EX_EVENT_CATCH
 291       && ex_event != EX_EVENT_RETHROW)
 292     error (_("Unsupported or unknown exception event; cannot catch it"));
 293
 294   handle_gnu_v3_exceptions (tempflag, cond_string, ex_event, from_tty);
 295 }
 296
 297 /* Implementation of "catch catch" command.  */
 298
 299 static void
 300 catch_catch_command (char *arg, int from_tty, struct cmd_list_element *command)
 301 {
 302   int tempflag = get_cmd_context (command) == CATCH_TEMPORARY;
 303
 304   catch_exception_command_1 (EX_EVENT_CATCH, arg, tempflag, from_tty);
 305 }
 306
 307 /* Implementation of "catch throw" command.  */
 308
 309 static void
 310 catch_throw_command (char *arg, int from_tty, struct cmd_list_element *command)
 311 {
 312   int tempflag = get_cmd_context (command) == CATCH_TEMPORARY;
 313
 314   catch_exception_command_1 (EX_EVENT_THROW, arg, tempflag, from_tty);
 315 }
 316
 317 /* Implementation of "catch rethrow" command.  */
 318
 319 static void
 320 catch_rethrow_command (char *arg, int from_tty,
 321                        struct cmd_list_element *command)
 322 {
 323   int tempflag = get_cmd_context (command) == CATCH_TEMPORARY;
 324
 325   catch_exception_command_1 (EX_EVENT_RETHROW, arg, tempflag, from_tty);
 326 }
 327
 328 \f
 329
 330 static void
 331 initialize_throw_catchpoint_ops (void)
 332 {
 333   struct breakpoint_ops *ops;
 334
 335   initialize_breakpoint_ops ();
 336
 337   /* GNU v3 exception catchpoints.  */
 338   ops = &gnu_v3_exception_catchpoint_ops;
 339   *ops = bkpt_breakpoint_ops;
 340   ops->re_set = re_set_exception_catchpoint;
 341   ops->print_it = print_it_exception_catchpoint;
 342   ops->print_one = print_one_exception_catchpoint;
 343   ops->print_mention = print_mention_exception_catchpoint;
 344   ops->print_recreate = print_recreate_exception_catchpoint;
 345 }
 346
 347 initialize_file_ftype _initialize_break_catch_throw;
 348
 349 void
 350 _initialize_break_catch_throw (void)
 351 {
 352   initialize_throw_catchpoint_ops ();
 353
 354   /* Add catch and tcatch sub-commands.  */
 355   add_catch_command ("catch", _("\
 356 Catch an exception, when caught."),
 357                      catch_catch_command,
 358                      NULL,
 359                      CATCH_PERMANENT,
 360                      CATCH_TEMPORARY);
 361   add_catch_command ("throw", _("\
 362 Catch an exception, when thrown."),
 363                      catch_throw_command,
 364                      NULL,
 365                      CATCH_PERMANENT,
 366                      CATCH_TEMPORARY);
 367   add_catch_command ("rethrow", _("\
 368 Catch an exception, when rethrown."),
 369                      catch_rethrow_command,
 370                      NULL,
 371                      CATCH_PERMANENT,
 372                      CATCH_TEMPORARY);
 373 }