gdb/reverse.c

   1 /* Reverse execution and reverse debugging.
   2
   3    Copyright (C) 2006-2017 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 "target.h"
  22 #include "top.h"
  23 #include "cli/cli-cmds.h"
  24 #include "cli/cli-decode.h"
  25 #include "cli/cli-utils.h"
  26 #include "inferior.h"
  27 #include "infrun.h"
  28 #include "regcache.h"
  29
  30 /* User interface:
  31    reverse-step, reverse-next etc.  */
  32
  33 static void
  34 exec_direction_default (void *notused)
  35 {
  36   /* Return execution direction to default state.  */
  37   execution_direction = EXEC_FORWARD;
  38 }
  39
  40 /* exec_reverse_once -- accepts an arbitrary gdb command (string),
  41    and executes it with exec-direction set to 'reverse'.
  42
  43    Used to implement reverse-next etc. commands.  */
  44
  45 static void
  46 exec_reverse_once (const char *cmd, char *args, int from_tty)
  47 {
  48   char *reverse_command;
  49   enum exec_direction_kind dir = execution_direction;
  50   struct cleanup *old_chain;
  51
  52   if (dir == EXEC_REVERSE)
  53     error (_("Already in reverse mode.  Use '%s' or 'set exec-dir forward'."),
  54            cmd);
  55
  56   if (!target_can_execute_reverse)
  57     error (_("Target %s does not support this command."), target_shortname);
  58
  59   reverse_command = xstrprintf ("%s %s", cmd, args ? args : "");
  60   old_chain = make_cleanup (exec_direction_default, NULL);
  61   make_cleanup (xfree, reverse_command);
  62   execution_direction = EXEC_REVERSE;
  63   execute_command (reverse_command, from_tty);
  64   do_cleanups (old_chain);
  65 }
  66
  67 static void
  68 reverse_step (char *args, int from_tty)
  69 {
  70   exec_reverse_once ("step", args, from_tty);
  71 }
  72
  73 static void
  74 reverse_stepi (char *args, int from_tty)
  75 {
  76   exec_reverse_once ("stepi", args, from_tty);
  77 }
  78
  79 static void
  80 reverse_next (char *args, int from_tty)
  81 {
  82   exec_reverse_once ("next", args, from_tty);
  83 }
  84
  85 static void
  86 reverse_nexti (char *args, int from_tty)
  87 {
  88   exec_reverse_once ("nexti", args, from_tty);
  89 }
  90
  91 static void
  92 reverse_continue (char *args, int from_tty)
  93 {
  94   exec_reverse_once ("continue", args, from_tty);
  95 }
  96
  97 static void
  98 reverse_finish (char *args, int from_tty)
  99 {
 100   exec_reverse_once ("finish", args, from_tty);
 101 }
 102
 103 /* Data structures for a bookmark list.  */
 104
 105 struct bookmark {
 106   struct bookmark *next;
 107   int number;
 108   CORE_ADDR pc;
 109   struct symtab_and_line sal;
 110   gdb_byte *opaque_data;
 111 };
 112
 113 static struct bookmark *bookmark_chain;
 114 static int bookmark_count;
 115
 116 #define ALL_BOOKMARKS(B) for ((B) = bookmark_chain; (B); (B) = (B)->next)
 117
 118 #define ALL_BOOKMARKS_SAFE(B,TMP)           \
 119      for ((B) = bookmark_chain;             \
 120           (B) ? ((TMP) = (B)->next, 1) : 0; \
 121           (B) = (TMP))
 122
 123 /* save_bookmark_command -- implement "bookmark" command.
 124    Call target method to get a bookmark identifier.
 125    Insert bookmark identifier into list.
 126
 127    Identifier will be a malloc string (gdb_byte *).
 128    Up to us to free it as required.  */
 129
 130 static void
 131 save_bookmark_command (char *args, int from_tty)
 132 {
 133   /* Get target's idea of a bookmark.  */
 134   gdb_byte *bookmark_id = target_get_bookmark (args, from_tty);
 135   struct bookmark *b, *b1;
 136   struct gdbarch *gdbarch = get_regcache_arch (get_current_regcache ());
 137
 138   /* CR should not cause another identical bookmark.  */
 139   dont_repeat ();
 140
 141   if (bookmark_id == NULL)
 142     error (_("target_get_bookmark failed."));
 143
 144   /* Set up a bookmark struct.  */
 145   b = XCNEW (struct bookmark);
 146   b->number = ++bookmark_count;
 147   init_sal (&b->sal);
 148   b->pc = regcache_read_pc (get_current_regcache ());
 149   b->sal = find_pc_line (b->pc, 0);
 150   b->sal.pspace = get_frame_program_space (get_current_frame ());
 151   b->opaque_data = bookmark_id;
 152   b->next = NULL;
 153
 154   /* Add this bookmark to the end of the chain, so that a list
 155      of bookmarks will come out in order of increasing numbers.  */
 156
 157   b1 = bookmark_chain;
 158   if (b1 == 0)
 159     bookmark_chain = b;
 160   else
 161     {
 162       while (b1->next)
 163         b1 = b1->next;
 164       b1->next = b;
 165     }
 166   printf_filtered (_("Saved bookmark %d at %s\n"), b->number,
 167                      paddress (gdbarch, b->sal.pc));
 168 }
 169
 170 /* Implement "delete bookmark" command.  */
 171
 172 static int
 173 delete_one_bookmark (int num)
 174 {
 175   struct bookmark *b1, *b;
 176
 177   /* Find bookmark with corresponding number.  */
 178   ALL_BOOKMARKS (b)
 179     if (b->number == num)
 180       break;
 181
 182   /* Special case, first item in list.  */
 183   if (b == bookmark_chain)
 184     bookmark_chain = b->next;
 185
 186   /* Find bookmark preceding "marked" one, so we can unlink.  */
 187   if (b)
 188     {
 189       ALL_BOOKMARKS (b1)
 190         if (b1->next == b)
 191           {
 192             /* Found designated bookmark.  Unlink and delete.  */
 193             b1->next = b->next;
 194             break;
 195           }
 196       xfree (b->opaque_data);
 197       xfree (b);
 198       return 1;         /* success */
 199     }
 200   return 0;             /* failure */
 201 }
 202
 203 static void
 204 delete_all_bookmarks (void)
 205 {
 206   struct bookmark *b, *b1;
 207
 208   ALL_BOOKMARKS_SAFE (b, b1)
 209     {
 210       xfree (b->opaque_data);
 211       xfree (b);
 212     }
 213   bookmark_chain = NULL;
 214 }
 215
 216 static void
 217 delete_bookmark_command (char *args, int from_tty)
 218 {
 219   if (bookmark_chain == NULL)
 220     {
 221       warning (_("No bookmarks."));
 222       return;
 223     }
 224
 225   if (args == NULL || args[0] == '\0')
 226     {
 227       if (from_tty && !query (_("Delete all bookmarks? ")))
 228         return;
 229       delete_all_bookmarks ();
 230       return;
 231     }
 232
 233   number_or_range_parser parser (args);
 234   while (!parser.finished ())
 235     {
 236       int num = parser.get_number ();
 237       if (!delete_one_bookmark (num))
 238         /* Not found.  */
 239         warning (_("No bookmark #%d."), num);
 240     }
 241 }
 242
 243 /* Implement "goto-bookmark" command.  */
 244
 245 static void
 246 goto_bookmark_command (char *args, int from_tty)
 247 {
 248   struct bookmark *b;
 249   unsigned long num;
 250   char *p = args;
 251
 252   if (args == NULL || args[0] == '\0')
 253     error (_("Command requires an argument."));
 254
 255   if (startswith (args, "start")
 256       || startswith (args, "begin")
 257       || startswith (args, "end"))
 258     {
 259       /* Special case.  Give target opportunity to handle.  */
 260       target_goto_bookmark ((gdb_byte *) args, from_tty);
 261       return;
 262     }
 263
 264   if (args[0] == '\'' || args[0] == '\"')
 265     {
 266       /* Special case -- quoted string.  Pass on to target.  */
 267       if (args[strlen (args) - 1] != args[0])
 268         error (_("Unbalanced quotes: %s"), args);
 269       target_goto_bookmark ((gdb_byte *) args, from_tty);
 270       return;
 271     }
 272
 273   /* General case.  Bookmark identified by bookmark number.  */
 274   num = get_number (&args);
 275
 276   if (num == 0)
 277     error (_("goto-bookmark: invalid bookmark number '%s'."), p);
 278
 279   ALL_BOOKMARKS (b)
 280     if (b->number == num)
 281       break;
 282
 283   if (b)
 284     {
 285       /* Found.  Send to target method.  */
 286       target_goto_bookmark (b->opaque_data, from_tty);
 287       return;
 288     }
 289   /* Not found.  */
 290   error (_("goto-bookmark: no bookmark found for '%s'."), p);
 291 }
 292
 293 static int
 294 bookmark_1 (int bnum)
 295 {
 296   struct gdbarch *gdbarch = get_regcache_arch (get_current_regcache ());
 297   struct bookmark *b;
 298   int matched = 0;
 299
 300   ALL_BOOKMARKS (b)
 301   {
 302     if (bnum == -1 || bnum == b->number)
 303       {
 304         printf_filtered ("   %d       %s    '%s'\n",
 305                          b->number,
 306                          paddress (gdbarch, b->pc),
 307                          b->opaque_data);
 308         matched++;
 309       }
 310   }
 311
 312   if (bnum > 0 && matched == 0)
 313     printf_filtered ("No bookmark #%d\n", bnum);
 314
 315   return matched;
 316 }
 317
 318 /* Implement "info bookmarks" command.  */
 319
 320 static void
 321 bookmarks_info (char *args, int from_tty)
 322 {
 323   if (!bookmark_chain)
 324     printf_filtered (_("No bookmarks.\n"));
 325   else if (args == NULL || *args == '\0')
 326     bookmark_1 (-1);
 327   else
 328     {
 329       number_or_range_parser parser (args);
 330       while (!parser.finished ())
 331         {
 332           int bnum = parser.get_number ();
 333           bookmark_1 (bnum);
 334         }
 335     }
 336 }
 337
 338
 339 /* Provide a prototype to silence -Wmissing-prototypes.  */
 340 extern initialize_file_ftype _initialize_reverse;
 341
 342 void
 343 _initialize_reverse (void)
 344 {
 345   add_com ("reverse-step", class_run, reverse_step, _("\
 346 Step program backward until it reaches the beginning of another source line.\n\
 347 Argument N means do this N times (or till program stops for another reason).")
 348            );
 349   add_com_alias ("rs", "reverse-step", class_alias, 1);
 350
 351   add_com ("reverse-next", class_run, reverse_next, _("\
 352 Step program backward, proceeding through subroutine calls.\n\
 353 Like the \"reverse-step\" command as long as subroutine calls do not happen;\n\
 354 when they do, the call is treated as one instruction.\n\
 355 Argument N means do this N times (or till program stops for another reason).")
 356            );
 357   add_com_alias ("rn", "reverse-next", class_alias, 1);
 358
 359   add_com ("reverse-stepi", class_run, reverse_stepi, _("\
 360 Step backward exactly one instruction.\n\
 361 Argument N means do this N times (or till program stops for another reason).")
 362            );
 363   add_com_alias ("rsi", "reverse-stepi", class_alias, 0);
 364
 365   add_com ("reverse-nexti", class_run, reverse_nexti, _("\
 366 Step backward one instruction, but proceed through called subroutines.\n\
 367 Argument N means do this N times (or till program stops for another reason).")
 368            );
 369   add_com_alias ("rni", "reverse-nexti", class_alias, 0);
 370
 371   add_com ("reverse-continue", class_run, reverse_continue, _("\
 372 Continue program being debugged but run it in reverse.\n\
 373 If proceeding from breakpoint, a number N may be used as an argument,\n\
 374 which means to set the ignore count of that breakpoint to N - 1 (so that\n\
 375 the breakpoint won't break until the Nth time it is reached)."));
 376   add_com_alias ("rc", "reverse-continue", class_alias, 0);
 377
 378   add_com ("reverse-finish", class_run, reverse_finish, _("\
 379 Execute backward until just before selected stack frame is called."));
 380
 381   add_com ("bookmark", class_bookmark, save_bookmark_command, _("\
 382 Set a bookmark in the program's execution history.\n\
 383 A bookmark represents a point in the execution history \n\
 384 that can be returned to at a later point in the debug session."));
 385   add_info ("bookmarks", bookmarks_info, _("\
 386 Status of user-settable bookmarks.\n\
 387 Bookmarks are user-settable markers representing a point in the \n\
 388 execution history that can be returned to later in the same debug \n\
 389 session."));
 390   add_cmd ("bookmark", class_bookmark, delete_bookmark_command, _("\
 391 Delete a bookmark from the bookmark list.\n\
 392 Argument is a bookmark number or numbers,\n\
 393  or no argument to delete all bookmarks.\n"),
 394            &deletelist);
 395   add_com ("goto-bookmark", class_bookmark, goto_bookmark_command, _("\
 396 Go to an earlier-bookmarked point in the program's execution history.\n\
 397 Argument is the bookmark number of a bookmark saved earlier by using \n\
 398 the 'bookmark' command, or the special arguments:\n\
 399   start (beginning of recording)\n\
 400   end   (end of recording)\n"));
 401 }