gdb/user-regs.c

   1 /* User visible, per-frame registers, for GDB, the GNU debugger.
   2
   3    Copyright (C) 2002, 2003, 2004, 2007, 2008, 2009
   4    Free Software Foundation, Inc.
   5
   6    Contributed by Red Hat.
   7
   8    This file is part of GDB.
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 3 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  22
  23 #include "defs.h"
  24 #include "user-regs.h"
  25 #include "gdbtypes.h"
  26 #include "gdb_string.h"
  27 #include "gdb_assert.h"
  28 #include "frame.h"
  29
  30 /* A table of user registers.
  31
  32    User registers have regnum's that live above of the range [0
  33    .. gdbarch_num_regs + gdbarch_num_pseudo_regs)
  34    (which is controlled by the target).
  35    The target should never see a user register's regnum value.
  36
  37    Always append, never delete.  By doing this, the relative regnum
  38    (offset from gdbarch_num_regs + gdbarch_num_pseudo_regs)
  39     assigned to each user  register never changes.  */
  40
  41 struct user_reg
  42 {
  43   const char *name;
  44   struct value *(*read) (struct frame_info * frame, const void *baton);
  45   const void *baton;
  46   struct user_reg *next;
  47 };
  48
  49 /* This structure is named gdb_user_regs instead of user_regs to avoid
  50    conflicts with any "struct user_regs" in system headers.  For instance,
  51    on ARM GNU/Linux native builds, nm-linux.h includes <signal.h> includes
  52    <sys/ucontext.h> includes <sys/procfs.h> includes <sys/user.h>, which
  53    declares "struct user_regs".  */
  54
  55 struct gdb_user_regs
  56 {
  57   struct user_reg *first;
  58   struct user_reg **last;
  59 };
  60
  61 static void
  62 append_user_reg (struct gdb_user_regs *regs, const char *name,
  63                  user_reg_read_ftype *read, const void *baton,
  64                  struct user_reg *reg)
  65 {
  66   /* The caller is responsible for allocating memory needed to store
  67      the register.  By doing this, the function can operate on a
  68      register list stored in the common heap or a specific obstack.  */
  69   gdb_assert (reg != NULL);
  70   reg->name = name;
  71   reg->read = read;
  72   reg->baton = baton;
  73   reg->next = NULL;
  74   (*regs->last) = reg;
  75   regs->last = &(*regs->last)->next;
  76 }
  77
  78 /* An array of the builtin user registers.  */
  79
  80 static struct gdb_user_regs builtin_user_regs = { NULL, &builtin_user_regs.first };
  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                    XMALLOC (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 = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct gdb_user_regs);
 100   regs->last = &regs->first;
 101   for (reg = builtin_user_regs.first; reg != NULL; reg = reg->next)
 102     append_user_reg (regs, reg->name, reg->read, reg->baton,
 103                      GDBARCH_OBSTACK_ZALLOC (gdbarch, struct user_reg));
 104   return regs;
 105 }
 106
 107 void
 108 user_reg_add (struct gdbarch *gdbarch, const char *name,
 109               user_reg_read_ftype *read, const void *baton)
 110 {
 111   struct gdb_user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
 112   if (regs == NULL)
 113     {
 114       /* ULGH, called during architecture initialization.  Patch
 115          things up.  */
 116       regs = user_regs_init (gdbarch);
 117       deprecated_set_gdbarch_data (gdbarch, user_regs_data, regs);
 118     }
 119   append_user_reg (regs, name, read, baton,
 120                    GDBARCH_OBSTACK_ZALLOC (gdbarch, struct user_reg));
 121 }
 122
 123 int
 124 user_reg_map_name_to_regnum (struct gdbarch *gdbarch, const char *name,
 125                              int len)
 126 {
 127   /* Make life easy, set the len to something reasonable.  */
 128   if (len < 0)
 129     len = strlen (name);
 130
 131   /* Search register name space first - always let an architecture
 132      specific register override the user registers.  */
 133   {
 134     int i;
 135     int maxregs = (gdbarch_num_regs (gdbarch)
 136                    + gdbarch_num_pseudo_regs (gdbarch));
 137     for (i = 0; i < maxregs; i++)
 138       {
 139         const char *regname = gdbarch_register_name (gdbarch, i);
 140         if (regname != NULL && len == strlen (regname)
 141             && strncmp (regname, name, len) == 0)
 142           {
 143             return i;
 144           }
 145       }
 146   }
 147
 148   /* Search the user name space.  */
 149   {
 150     struct gdb_user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
 151     struct user_reg *reg;
 152     int nr;
 153     for (nr = 0, reg = regs->first; reg != NULL; reg = reg->next, nr++)
 154       {
 155         if ((len < 0 && strcmp (reg->name, name))
 156             || (len == strlen (reg->name)
 157                 && strncmp (reg->name, name, len) == 0))
 158           return gdbarch_num_regs (gdbarch)
 159                  + gdbarch_num_pseudo_regs (gdbarch) + nr;
 160       }
 161   }
 162
 163   return -1;
 164 }
 165
 166 static struct user_reg *
 167 usernum_to_user_reg (struct gdbarch *gdbarch, int usernum)
 168 {
 169   struct gdb_user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
 170   struct user_reg *reg;
 171   for (reg = regs->first; reg != NULL; reg = reg->next)
 172     {
 173       if (usernum == 0)
 174         return reg;
 175       usernum--;
 176     }
 177   return NULL;
 178 }
 179
 180 const char *
 181 user_reg_map_regnum_to_name (struct gdbarch *gdbarch, int regnum)
 182 {
 183   int maxregs = (gdbarch_num_regs (gdbarch)
 184                  + gdbarch_num_pseudo_regs (gdbarch));
 185   if (regnum < 0)
 186     return NULL;
 187   else if (regnum < maxregs)
 188     return gdbarch_register_name (gdbarch, regnum);
 189   else
 190     {
 191       struct user_reg *reg = usernum_to_user_reg (gdbarch, regnum - maxregs);
 192       if (reg == NULL)
 193         return NULL;
 194       else
 195         return reg->name;
 196     }
 197 }
 198
 199 struct value *
 200 value_of_user_reg (int regnum, struct frame_info *frame)
 201 {
 202   struct gdbarch *gdbarch = get_frame_arch (frame);
 203   int maxregs = (gdbarch_num_regs (gdbarch)
 204                  + gdbarch_num_pseudo_regs (gdbarch));
 205   struct user_reg *reg = usernum_to_user_reg (gdbarch, regnum - maxregs);
 206   gdb_assert (reg != NULL);
 207   return reg->read (frame, reg->baton);
 208 }
 209
 210 extern initialize_file_ftype _initialize_user_regs; /* -Wmissing-prototypes */
 211
 212 void
 213 _initialize_user_regs (void)
 214 {
 215   user_regs_data = gdbarch_data_register_post_init (user_regs_init);
 216 }