gdb/user-regs.c

   1 /* User visible, per-frame registers, for GDB, the GNU debugger.
   2
   3    Copyright (C) 2002-2014 Free Software Foundation, Inc.
   4
   5    Contributed by Red Hat.
   6
   7    This file is part of GDB.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  21
  22 #include "defs.h"
  23 #include "user-regs.h"
  24 #include "gdbtypes.h"
  25 #include <string.h>
  26 #include "frame.h"
  27
  28 /* A table of user registers.
  29
  30    User registers have regnum's that live above of the range [0
  31    .. gdbarch_num_regs + gdbarch_num_pseudo_regs)
  32    (which is controlled by the target).
  33    The target should never see a user register's regnum value.
  34
  35    Always append, never delete.  By doing this, the relative regnum
  36    (offset from gdbarch_num_regs + gdbarch_num_pseudo_regs)
  37     assigned to each user  register never changes.  */
  38
  39 struct user_reg
  40 {
  41   const char *name;
  42   struct value *(*read) (struct frame_info * frame, const void *baton);
  43   const void *baton;
  44   struct user_reg *next;
  45 };
  46
  47 /* This structure is named gdb_user_regs instead of user_regs to avoid
  48    conflicts with any "struct user_regs" in system headers.  For instance,
  49    on ARM GNU/Linux native builds, nm-linux.h includes <signal.h> includes
  50    <sys/ucontext.h> includes <sys/procfs.h> includes <sys/user.h>, which
  51    declares "struct user_regs".  */
  52
  53 struct gdb_user_regs
  54 {
  55   struct user_reg *first;
  56   struct user_reg **last;
  57 };
  58
  59 static void
  60 append_user_reg (struct gdb_user_regs *regs, const char *name,
  61                  user_reg_read_ftype *read, const void *baton,
  62                  struct user_reg *reg)
  63 {
  64   /* The caller is responsible for allocating memory needed to store
  65      the register.  By doing this, the function can operate on a
  66      register list stored in the common heap or a specific obstack.  */
  67   gdb_assert (reg != NULL);
  68   reg->name = name;
  69   reg->read = read;
  70   reg->baton = baton;
  71   reg->next = NULL;
  72   (*regs->last) = reg;
  73   regs->last = &(*regs->last)->next;
  74 }
  75
  76 /* An array of the builtin user registers.  */
  77
  78 static struct gdb_user_regs builtin_user_regs = {
  79   NULL, &builtin_user_regs.first
  80 };
  81
  82 void
  83 user_reg_add_builtin (const char *name, user_reg_read_ftype *read,
  84                       const void *baton)
  85 {
  86   append_user_reg (&builtin_user_regs, name, read, baton,
  87                    XNEW (struct user_reg));
  88 }
  89
  90 /* Per-architecture user registers.  Start with the builtin user
  91    registers and then, again, append.  */
  92
  93 static struct gdbarch_data *user_regs_data;
  94
  95 static void *
  96 user_regs_init (struct gdbarch *gdbarch)
  97 {
  98   struct user_reg *reg;
  99   struct gdb_user_regs *regs
 100     = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct gdb_user_regs);
 101
 102   regs->last = &regs->first;
 103   for (reg = builtin_user_regs.first; reg != NULL; reg = reg->next)
 104     append_user_reg (regs, reg->name, reg->read, reg->baton,
 105                      GDBARCH_OBSTACK_ZALLOC (gdbarch, struct user_reg));
 106   return regs;
 107 }
 108
 109 void
 110 user_reg_add (struct gdbarch *gdbarch, const char *name,
 111               user_reg_read_ftype *read, const void *baton)
 112 {
 113   struct gdb_user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
 114
 115   if (regs == NULL)
 116     {
 117       /* ULGH, called during architecture initialization.  Patch
 118          things up.  */
 119       regs = user_regs_init (gdbarch);
 120       deprecated_set_gdbarch_data (gdbarch, user_regs_data, regs);
 121     }
 122   append_user_reg (regs, name, read, baton,
 123                    GDBARCH_OBSTACK_ZALLOC (gdbarch, struct user_reg));
 124 }
 125
 126 int
 127 user_reg_map_name_to_regnum (struct gdbarch *gdbarch, const char *name,
 128                              int len)
 129 {
 130   /* Make life easy, set the len to something reasonable.  */
 131   if (len < 0)
 132     len = strlen (name);
 133
 134   /* Search register name space first - always let an architecture
 135      specific register override the user registers.  */
 136   {
 137     int i;
 138     int maxregs = (gdbarch_num_regs (gdbarch)
 139                    + gdbarch_num_pseudo_regs (gdbarch));
 140
 141     for (i = 0; i < maxregs; i++)
 142       {
 143         const char *regname = gdbarch_register_name (gdbarch, i);
 144
 145         if (regname != NULL && len == strlen (regname)
 146             && strncmp (regname, name, len) == 0)
 147           {
 148             return i;
 149           }
 150       }
 151   }
 152
 153   /* Search the user name space.  */
 154   {
 155     struct gdb_user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
 156     struct user_reg *reg;
 157     int nr;
 158
 159     for (nr = 0, reg = regs->first; reg != NULL; reg = reg->next, nr++)
 160       {
 161         if ((len < 0 && strcmp (reg->name, name))
 162             || (len == strlen (reg->name)
 163                 && strncmp (reg->name, name, len) == 0))
 164           return gdbarch_num_regs (gdbarch)
 165                  + gdbarch_num_pseudo_regs (gdbarch) + nr;
 166       }
 167   }
 168
 169   return -1;
 170 }
 171
 172 static struct user_reg *
 173 usernum_to_user_reg (struct gdbarch *gdbarch, int usernum)
 174 {
 175   struct gdb_user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
 176   struct user_reg *reg;
 177
 178   for (reg = regs->first; reg != NULL; reg = reg->next)
 179     {
 180       if (usernum == 0)
 181         return reg;
 182       usernum--;
 183     }
 184   return NULL;
 185 }
 186
 187 const char *
 188 user_reg_map_regnum_to_name (struct gdbarch *gdbarch, int regnum)
 189 {
 190   int maxregs = (gdbarch_num_regs (gdbarch)
 191                  + gdbarch_num_pseudo_regs (gdbarch));
 192
 193   if (regnum < 0)
 194     return NULL;
 195   else if (regnum < maxregs)
 196     return gdbarch_register_name (gdbarch, regnum);
 197   else
 198     {
 199       struct user_reg *reg = usernum_to_user_reg (gdbarch, regnum - maxregs);
 200       if (reg == NULL)
 201         return NULL;
 202       else
 203         return reg->name;
 204     }
 205 }
 206
 207 struct value *
 208 value_of_user_reg (int regnum, struct frame_info *frame)
 209 {
 210   struct gdbarch *gdbarch = get_frame_arch (frame);
 211   int maxregs = (gdbarch_num_regs (gdbarch)
 212                  + gdbarch_num_pseudo_regs (gdbarch));
 213   struct user_reg *reg = usernum_to_user_reg (gdbarch, regnum - maxregs);
 214
 215   gdb_assert (reg != NULL);
 216   return reg->read (frame, reg->baton);
 217 }
 218
 219 extern initialize_file_ftype _initialize_user_regs; /* -Wmissing-prototypes */
 220
 221 void
 222 _initialize_user_regs (void)
 223 {
 224   user_regs_data = gdbarch_data_register_post_init (user_regs_init);
 225 }