gdb/reverse.c

   1 /* Reverse execution and reverse debugging.
   2
   3    Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011
   4    Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "gdb_string.h"
  23 #include "target.h"
  24 #include "top.h"
  25 #include "cli/cli-cmds.h"
  26 #include "cli/cli-decode.h"
  27 #include "inferior.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 (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_ERROR)
  53     error (_("Target %s does not support this command."), target_shortname);
  54
  55   if (dir == EXEC_REVERSE)
  56     error (_("Already in reverse mode.  Use '%s' or 'set exec-dir forward'."),
  57            cmd);
  58
  59   if (!target_can_execute_reverse)
  60     error (_("Target %s does not support this command."), target_shortname);
  61
  62   reverse_command = xstrprintf ("%s %s", cmd, args ? args : "");
  63   old_chain = make_cleanup (exec_direction_default, NULL);
  64   make_cleanup (xfree, reverse_command);
  65   execution_direction = EXEC_REVERSE;
  66   execute_command (reverse_command, from_tty);
  67   do_cleanups (old_chain);
  68 }
  69
  70 static void
  71 reverse_step (char *args, int from_tty)
  72 {
  73   exec_reverse_once ("step", args, from_tty);
  74 }
  75
  76 static void
  77 reverse_stepi (char *args, int from_tty)
  78 {
  79   exec_reverse_once ("stepi", args, from_tty);
  80 }
  81
  82 static void
  83 reverse_next (char *args, int from_tty)
  84 {
  85   exec_reverse_once ("next", args, from_tty);
  86 }
  87
  88 static void
  89 reverse_nexti (char *args, int from_tty)
  90 {
  91   exec_reverse_once ("nexti", args, from_tty);
  92 }
  93
  94 static void
  95 reverse_continue (char *args, int from_tty)
  96 {
  97   exec_reverse_once ("continue", args, from_tty);
  98 }
  99
 100 static void
 101 reverse_finish (char *args, int from_tty)
 102 {
 103   exec_reverse_once ("finish", args, from_tty);
 104 }
 105
 106 /* Data structures for a bookmark list.  */
 107
 108 struct bookmark {
 109   struct bookmark *next;
 110   int number;
 111   CORE_ADDR pc;
 112   struct symtab_and_line sal;
 113   gdb_byte *opaque_data;
 114 };
 115
 116 static struct bookmark *bookmark_chain;
 117 static int bookmark_count;
 118
 119 #define ALL_BOOKMARKS(B) for ((B) = bookmark_chain; (B); (B) = (B)->next)
 120
 121 #define ALL_BOOKMARKS_SAFE(B,TMP)           \
 122      for ((B) = bookmark_chain;             \
 123           (B) ? ((TMP) = (B)->next, 1) : 0; \
 124           (B) = (TMP))
 125
 126 /* save_bookmark_command -- implement "bookmark" command.
 127    Call target method to get a bookmark identifier.
 128    Insert bookmark identifier into list.
 129
 130    Identifier will be a malloc string (gdb_byte *).
 131    Up to us to free it as required.  */
 132
 133 static void
 134 save_bookmark_command (char *args, int from_tty)
 135 {
 136   /* Get target's idea of a bookmark.  */
 137   gdb_byte *bookmark_id = target_get_bookmark (args, from_tty);
 138   struct bookmark *b, *b1;
 139   struct gdbarch *gdbarch = get_regcache_arch (get_current_regcache ());
 140
 141   /* CR should not cause another identical bookmark.  */
 142   dont_repeat ();
 143
 144   if (bookmark_id == NULL)
 145     error (_("target_get_bookmark failed."));
 146
 147   /* Set up a bookmark struct.  */
 148   b = xcalloc (1, sizeof (struct bookmark));
 149   b->number = ++bookmark_count;
 150   init_sal (&b->sal);
 151   b->pc = regcache_read_pc (get_current_regcache ());
 152   b->sal = find_pc_line (b->pc, 0);
 153   b->sal.pspace = get_frame_program_space (get_current_frame ());
 154   b->opaque_data = bookmark_id;
 155   b->next = NULL;
 156
 157   /* Add this bookmark to the end of the chain, so that a list
 158      of bookmarks will come out in order of increasing numbers.  */
 159
 160   b1 = bookmark_chain;
 161   if (b1 == 0)
 162     bookmark_chain = b;
 163   else
 164     {
 165       while (b1->next)
 166         b1 = b1->next;
 167       b1->next = b;
 168     }
 169   printf_filtered (_("Saved bookmark %d at %s\n"), b->number,
 170                      paddress (gdbarch, b->sal.pc));
 171 }
 172
 173 /* Implement "delete bookmark" command.  */
 174
 175 static int
 176 delete_one_bookmark (int num)
 177 {
 178   struct bookmark *b1, *b;
 179
 180   /* Find bookmark with corresponding number.  */
 181   ALL_BOOKMARKS (b)
 182     if (b->number == num)
 183       break;
 184
 185   /* Special case, first item in list.  */
 186   if (b == bookmark_chain)
 187     bookmark_chain = b->next;
 188
 189   /* Find bookmark preceeding "marked" one, so we can unlink.  */
 190   if (b)
 191     {
 192       ALL_BOOKMARKS (b1)
 193         if (b1->next == b)
 194           {
 195             /* Found designated bookmark.  Unlink and delete.  */
 196             b1->next = b->next;
 197             break;
 198           }
 199       xfree (b->opaque_data);
 200       xfree (b);
 201       return 1;         /* success */
 202     }
 203   return 0;             /* failure */
 204 }
 205
 206 static void
 207 delete_all_bookmarks (void)
 208 {
 209   struct bookmark *b, *b1;
 210
 211   ALL_BOOKMARKS_SAFE (b, b1)
 212     {
 213       xfree (b->opaque_data);
 214       xfree (b);
 215     }
 216   bookmark_chain = NULL;
 217 }
 218
 219 static void
 220 delete_bookmark_command (char *args, int from_tty)
 221 {
 222   struct bookmark *b;
 223   int num;
 224
 225   if (bookmark_chain == NULL)
 226     {
 227       warning (_("No bookmarks."));
 228       return;
 229     }
 230
 231   if (args == NULL || args[0] == '\0')
 232     {
 233       if (from_tty && !query (_("Delete all bookmarks? ")))
 234         return;
 235       delete_all_bookmarks ();
 236       return;
 237     }
 238
 239   while (args != NULL && *args != '\0')
 240     {
 241       num = get_number_or_range (&args);
 242       if (!delete_one_bookmark (num))
 243         /* Not found.  */
 244         warning (_("No bookmark #%d."), num);
 245     }
 246 }
 247
 248 /* Implement "goto-bookmark" command.  */
 249
 250 static void
 251 goto_bookmark_command (char *args, int from_tty)
 252 {
 253   struct bookmark *b;
 254   unsigned long num;
 255
 256   if (args == NULL || args[0] == '\0')
 257     error (_("Command requires an argument."));
 258
 259   if (strncmp (args, "start", strlen ("start")) == 0
 260       || strncmp (args, "begin", strlen ("begin")) == 0
 261       || strncmp (args, "end",   strlen ("end")) == 0)
 262     {
 263       /* Special case.  Give target opportunity to handle.  */
 264       target_goto_bookmark (args, from_tty);
 265       return;
 266     }
 267
 268   if (args[0] == '\'' || args[0] == '\"')
 269     {
 270       /* Special case -- quoted string.  Pass on to target.  */
 271       if (args[strlen (args) - 1] != args[0])
 272         error (_("Unbalanced quotes: %s"), args);
 273       target_goto_bookmark (args, from_tty);
 274       return;
 275     }
 276
 277   /* General case.  Bookmark identified by bookmark number.  */
 278   num = get_number (&args);
 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'."), args);
 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   int bnum = -1;
 324
 325   if (!bookmark_chain)
 326     printf_filtered (_("No bookmarks.\n"));
 327   else if (args == NULL || *args == '\0')
 328     bookmark_1 (-1);
 329   else
 330     while (args != NULL && *args != '\0')
 331       {
 332         bnum = get_number_or_range (&args);
 333         bookmark_1 (bnum);
 334       }
 335 }
 336
 337
 338 /* Provide a prototype to silence -Wmissing-prototypes.  */
 339 extern initialize_file_ftype _initialize_reverse;
 340
 341 void
 342 _initialize_reverse (void)
 343 {
 344   add_com ("reverse-step", class_run, reverse_step, _("\
 345 Step program backward until it reaches the beginning of another source line.\n\
 346 Argument N means do this N times (or till program stops for another reason).")
 347            );
 348   add_com_alias ("rs", "reverse-step", class_alias, 1);
 349
 350   add_com ("reverse-next", class_run, reverse_next, _("\
 351 Step program backward, proceeding through subroutine calls.\n\
 352 Like the \"reverse-step\" command as long as subroutine calls do not happen;\n\
 353 when they do, the call is treated as one instruction.\n\
 354 Argument N means do this N times (or till program stops for another reason).")
 355            );
 356   add_com_alias ("rn", "reverse-next", class_alias, 1);
 357
 358   add_com ("reverse-stepi", class_run, reverse_stepi, _("\
 359 Step backward exactly one instruction.\n\
 360 Argument N means do this N times (or till program stops for another reason).")
 361            );
 362   add_com_alias ("rsi", "reverse-stepi", class_alias, 0);
 363
 364   add_com ("reverse-nexti", class_run, reverse_nexti, _("\
 365 Step backward one instruction, but proceed through called subroutines.\n\
 366 Argument N means do this N times (or till program stops for another reason).")
 367            );
 368   add_com_alias ("rni", "reverse-nexti", class_alias, 0);
 369
 370   add_com ("reverse-continue", class_run, reverse_continue, _("\
 371 Continue program being debugged but run it in reverse.\n\
 372 If proceeding from breakpoint, a number N may be used as an argument,\n\
 373 which means to set the ignore count of that breakpoint to N - 1 (so that\n\
 374 the breakpoint won't break until the Nth time it is reached)."));
 375   add_com_alias ("rc", "reverse-continue", class_alias, 0);
 376
 377   add_com ("reverse-finish", class_run, reverse_finish, _("\
 378 Execute backward until just before selected stack frame is called."));
 379
 380   add_com ("bookmark", class_bookmark, save_bookmark_command, _("\
 381 Set a bookmark in the program's execution history.\n\
 382 A bookmark represents a point in the execution history \n\
 383 that can be returned to at a later point in the debug session."));
 384   add_info ("bookmarks", bookmarks_info, _("\
 385 Status of user-settable bookmarks.\n\
 386 Bookmarks are user-settable markers representing a point in the \n\
 387 execution history that can be returned to later in the same debug \n\
 388 session."));
 389   add_cmd ("bookmark", class_bookmark, delete_bookmark_command, _("\
 390 Delete a bookmark from the bookmark list.\n\
 391 Argument is a bookmark number or numbers,\n\
 392  or no argument to delete all bookmarks.\n"),
 393            &deletelist);
 394   add_com ("goto-bookmark", class_bookmark, goto_bookmark_command, _("\
 395 Go to an earlier-bookmarked point in the program's execution history.\n\
 396 Argument is the bookmark number of a bookmark saved earlier by using \n\
 397 the 'bookmark' command, or the special arguments:\n\
 398   start (beginning of recording)\n\
 399   end   (end of recording)\n"));
 400 }