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 "gdb_assert.h"
  27 #include "frame.h"
  28
  29 /* A table of user registers.
  30
  31    User registers have regnum's that live above of the range [0
  32    .. gdbarch_num_regs + gdbarch_num_pseudo_regs)
  33    (which is controlled by the target).
  34    The target should never see a user register's regnum value.
  35
  36    Always append, never delete.  By doing this, the relative regnum
  37    (offset from gdbarch_num_regs + gdbarch_num_pseudo_regs)
  38     assigned to each user  register never changes.  */
  39
  40 struct user_reg
  41 {
  42   const char *name;
  43   struct value *(*read) (struct frame_info * frame, const void *baton);
  44   const void *baton;
  45   struct user_reg *next;
  46 };
  47
  48 /* This structure is named gdb_user_regs instead of user_regs to avoid
  49    conflicts with any "struct user_regs" in system headers.  For instance,
  50    on ARM GNU/Linux native builds, nm-linux.h includes <signal.h> includes
  51    <sys/ucontext.h> includes <sys/procfs.h> includes <sys/user.h>, which
  52    declares "struct user_regs".  */
  53
  54 struct gdb_user_regs
  55 {
  56   struct user_reg *first;
  57   struct user_reg **last;
  58 };
  59
  60 static void
  61 append_user_reg (struct gdb_user_regs *regs, const char *name,
  62                  user_reg_read_ftype *read, const void *baton,
  63                  struct user_reg *reg)
  64 {
  65   /* The caller is responsible for allocating memory needed to store
  66      the register.  By doing this, the function can operate on a
  67      register list stored in the common heap or a specific obstack.  */
  68   gdb_assert (reg != NULL);
  69   reg->name = name;
  70   reg->read = read;
  71   reg->baton = baton;
  72   reg->next = NULL;
  73   (*regs->last) = reg;
  74   regs->last = &(*regs->last)->next;
  75 }
  76
  77 /* An array of the builtin user registers.  */
  78
  79 static struct gdb_user_regs builtin_user_regs = {
  80   NULL, &builtin_user_regs.first
  81 };
  82
  83 void
  84 user_reg_add_builtin (const char *name, user_reg_read_ftype *read,
  85                       const void *baton)
  86 {
  87   append_user_reg (&builtin_user_regs, name, read, baton,
  88                    XNEW (struct user_reg));
  89 }
  90
  91 /* Per-architecture user registers.  Start with the builtin user
  92    registers and then, again, append.  */
  93
  94 static struct gdbarch_data *user_regs_data;
  95
  96 static void *
  97 user_regs_init (struct gdbarch *gdbarch)
  98 {
  99   struct user_reg *reg;
 100   struct gdb_user_regs *regs
 101     = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct gdb_user_regs);
 102
 103   regs->last = &regs->first;
 104   for (reg = builtin_user_regs.first; reg != NULL; reg = reg->next)
 105     append_user_reg (regs, reg->name, reg->read, reg->baton,
 106                      GDBARCH_OBSTACK_ZALLOC (gdbarch, struct user_reg));
 107   return regs;
 108 }
 109
 110 void
 111 user_reg_add (struct gdbarch *gdbarch, const char *name,
 112               user_reg_read_ftype *read, const void *baton)
 113 {
 114   struct gdb_user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
 115
 116   if (regs == NULL)
 117     {
 118       /* ULGH, called during architecture initialization.  Patch
 119          things up.  */
 120       regs = user_regs_init (gdbarch);
 121       deprecated_set_gdbarch_data (gdbarch, user_regs_data, regs);
 122     }
 123   append_user_reg (regs, name, read, baton,
 124                    GDBARCH_OBSTACK_ZALLOC (gdbarch, struct user_reg));
 125 }
 126
 127 int
 128 user_reg_map_name_to_regnum (struct gdbarch *gdbarch, const char *name,
 129                              int len)
 130 {
 131   /* Make life easy, set the len to something reasonable.  */
 132   if (len < 0)
 133     len = strlen (name);
 134
 135   /* Search register name space first - always let an architecture
 136      specific register override the user registers.  */
 137   {
 138     int i;
 139     int maxregs = (gdbarch_num_regs (gdbarch)
 140                    + gdbarch_num_pseudo_regs (gdbarch));
 141
 142     for (i = 0; i < maxregs; i++)
 143       {
 144         const char *regname = gdbarch_register_name (gdbarch, i);
 145
 146         if (regname != NULL && len == strlen (regname)
 147             && strncmp (regname, name, len) == 0)
 148           {
 149             return i;
 150           }
 151       }
 152   }
 153
 154   /* Search the user name space.  */
 155   {
 156     struct gdb_user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
 157     struct user_reg *reg;
 158     int nr;
 159
 160     for (nr = 0, reg = regs->first; reg != NULL; reg = reg->next, nr++)
 161       {
 162         if ((len < 0 && strcmp (reg->name, name))
 163             || (len == strlen (reg->name)
 164                 && strncmp (reg->name, name, len) == 0))
 165           return gdbarch_num_regs (gdbarch)
 166                  + gdbarch_num_pseudo_regs (gdbarch) + nr;
 167       }
 168   }
 169
 170   return -1;
 171 }
 172
 173 static struct user_reg *
 174 usernum_to_user_reg (struct gdbarch *gdbarch, int usernum)
 175 {
 176   struct gdb_user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
 177   struct user_reg *reg;
 178
 179   for (reg = regs->first; reg != NULL; reg = reg->next)
 180     {
 181       if (usernum == 0)
 182         return reg;
 183       usernum--;
 184     }
 185   return NULL;
 186 }
 187
 188 const char *
 189 user_reg_map_regnum_to_name (struct gdbarch *gdbarch, int regnum)
 190 {
 191   int maxregs = (gdbarch_num_regs (gdbarch)
 192                  + gdbarch_num_pseudo_regs (gdbarch));
 193
 194   if (regnum < 0)
 195     return NULL;
 196   else if (regnum < maxregs)
 197     return gdbarch_register_name (gdbarch, regnum);
 198   else
 199     {
 200       struct user_reg *reg = usernum_to_user_reg (gdbarch, regnum - maxregs);
 201       if (reg == NULL)
 202         return NULL;
 203       else
 204         return reg->name;
 205     }
 206 }
 207
 208 struct value *
 209 value_of_user_reg (int regnum, struct frame_info *frame)
 210 {
 211   struct gdbarch *gdbarch = get_frame_arch (frame);
 212   int maxregs = (gdbarch_num_regs (gdbarch)
 213                  + gdbarch_num_pseudo_regs (gdbarch));
 214   struct user_reg *reg = usernum_to_user_reg (gdbarch, regnum - maxregs);
 215
 216   gdb_assert (reg != NULL);
 217   return reg->read (frame, reg->baton);
 218 }
 219
 220 extern initialize_file_ftype _initialize_user_regs; /* -Wmissing-prototypes */
 221
 222 void
 223 _initialize_user_regs (void)
 224 {
 225   user_regs_data = gdbarch_data_register_post_init (user_regs_init);
 226 }