gdb/reverse.c

   1 /* Reverse execution and reverse debugging.
   2
   3    Copyright (C) 2006, 2007, 2008, 2009 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 2 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, write to the Free Software
  19    Foundation, Inc., 51 Franklin Street, Fifth Floor,
  20    Boston, MA 02110-1301, USA.  */
  21
  22 #include "defs.h"
  23 #include "gdb_string.h"
  24 #include "target.h"
  25 #include "top.h"
  26 #include "cli/cli-cmds.h"
  27 #include "cli/cli-decode.h"
  28 #include "inferior.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 /* Provide a prototype to silence -Wmissing-prototypes.  */
 107 extern initialize_file_ftype _initialize_reverse;
 108
 109 void
 110 _initialize_reverse (void)
 111 {
 112   add_com ("reverse-step", class_run, reverse_step, _("\
 113 Step program backward until it reaches the beginning of another source line.\n\
 114 Argument N means do this N times (or till program stops for another reason).")
 115            );
 116   add_com_alias ("rs", "reverse-step", class_alias, 1);
 117
 118   add_com ("reverse-next", class_run, reverse_next, _("\
 119 Step program backward, proceeding through subroutine calls.\n\
 120 Like the \"reverse-step\" command as long as subroutine calls do not happen;\n\
 121 when they do, the call is treated as one instruction.\n\
 122 Argument N means do this N times (or till program stops for another reason).")
 123            );
 124   add_com_alias ("rn", "reverse-next", class_alias, 1);
 125
 126   add_com ("reverse-stepi", class_run, reverse_stepi, _("\
 127 Step backward exactly one instruction.\n\
 128 Argument N means do this N times (or till program stops for another reason).")
 129            );
 130   add_com_alias ("rsi", "reverse-stepi", class_alias, 0);
 131
 132   add_com ("reverse-nexti", class_run, reverse_nexti, _("\
 133 Step backward one instruction, but proceed through called subroutines.\n\
 134 Argument N means do this N times (or till program stops for another reason).")
 135            );
 136   add_com_alias ("rni", "reverse-nexti", class_alias, 0);
 137
 138   add_com ("reverse-continue", class_run, reverse_continue, _("\
 139 Continue program being debugged but run it in reverse.\n\
 140 If proceeding from breakpoint, a number N may be used as an argument,\n\
 141 which means to set the ignore count of that breakpoint to N - 1 (so that\n\
 142 the breakpoint won't break until the Nth time it is reached)."));
 143   add_com_alias ("rc", "reverse-continue", class_alias, 0);
 144
 145   add_com ("reverse-finish", class_run, reverse_finish, _("\
 146 Execute backward until just before selected stack frame is called."));
 147 }