gdb/user-regs.c

   1 /* User visible, per-frame registers, for GDB, the GNU debugger.
   2
   3    Copyright 2002 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 2 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, write to the Free Software
  21    Foundation, Inc., 59 Temple Place - Suite 330,
  22    Boston, MA 02111-1307, USA.  */
  23
  24 #include "defs.h"
  25 #include "user-regs.h"
  26 #include "gdbtypes.h"
  27 #include "gdb_string.h"
  28 #include "gdb_assert.h"
  29 #include "frame.h"
  30
  31 /* A table of user registers.
  32
  33    User registers have regnum's that live above of the range [0
  34    .. NUM_REGS + NUM_PSEUDO_REGS) (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 NUM_REGS + NUM_PSEUDO_REGS) assigned to each user
  39    register never changes.  */
  40
  41 struct user_reg
  42 {
  43   const char *name;
  44   struct value *(*read) (struct frame_info * frame);
  45   struct user_reg *next;
  46 };
  47
  48 struct user_regs
  49 {
  50   struct user_reg *first;
  51   struct user_reg **last;
  52 };
  53
  54 static void
  55 append_user_reg (struct user_regs *regs, const char *name,
  56                  user_reg_read_ftype *read, struct user_reg *reg)
  57 {
  58   /* The caller is responsible for allocating memory needed to store
  59      the register.  By doing this, the function can operate on a
  60      register list stored in the common heap or a specific obstack.  */
  61   gdb_assert (reg != NULL);
  62   reg->name = name;
  63   reg->read = read;
  64   reg->next = NULL;
  65   (*regs->last) = reg;
  66   regs->last = &(*regs->last)->next;
  67 }
  68
  69 /* An array of the builtin user registers.  */
  70
  71 static struct user_regs builtin_user_regs = { NULL, &builtin_user_regs.first };
  72
  73 void
  74 user_reg_add_builtin (const char *name, user_reg_read_ftype *read)
  75 {
  76   append_user_reg (&builtin_user_regs, name, read,
  77                    XMALLOC (struct user_reg));
  78 }
  79
  80 /* Per-architecture user registers.  Start with the builtin user
  81    registers and then, again, append.  */
  82
  83 static struct gdbarch_data *user_regs_data;
  84
  85 static void *
  86 user_regs_init (struct gdbarch *gdbarch)
  87 {
  88   struct user_reg *reg;
  89   struct user_regs *regs = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct user_regs);
  90   regs->last = &regs->first;
  91   for (reg = builtin_user_regs.first; reg != NULL; reg = reg->next)
  92     append_user_reg (regs, reg->name, reg->read,
  93                      GDBARCH_OBSTACK_ZALLOC (gdbarch, struct user_reg));
  94   return regs;
  95 }
  96
  97 void
  98 user_reg_add (struct gdbarch *gdbarch, const char *name,
  99                  user_reg_read_ftype *read)
 100 {
 101   struct user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
 102   if (regs == NULL)
 103     {
 104       /* ULGH, called during architecture initialization.  Patch
 105          things up.  */
 106       regs = user_regs_init (gdbarch);
 107       set_gdbarch_data (gdbarch, user_regs_data, regs);
 108     }
 109   append_user_reg (regs, name, read,
 110                    GDBARCH_OBSTACK_ZALLOC (gdbarch, struct user_reg));
 111 }
 112
 113 int
 114 user_reg_map_name_to_regnum (struct gdbarch *gdbarch, const char *name,
 115                              int len)
 116 {
 117   /* Make life easy, set the len to something reasonable.  */
 118   if (len < 0)
 119     len = strlen (name);
 120
 121   /* Search register name space first - always let an architecture
 122      specific register override the user registers.  */
 123   {
 124     int i;
 125     int maxregs = (gdbarch_num_regs (gdbarch)
 126                    + gdbarch_num_pseudo_regs (gdbarch));
 127     for (i = 0; i < maxregs; i++)
 128       {
 129         const char *regname = gdbarch_register_name (gdbarch, i);
 130         if (regname != NULL && len == strlen (regname)
 131             && strncmp (regname, name, len) == 0)
 132           {
 133             return i;
 134           }
 135       }
 136   }
 137
 138   /* Search the user name space.  */
 139   {
 140     struct user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
 141     struct user_reg *reg;
 142     int nr;
 143     for (nr = 0, reg = regs->first; reg != NULL; reg = reg->next, nr++)
 144       {
 145         if ((len < 0 && strcmp (reg->name, name))
 146             || (len == strlen (reg->name)
 147                 && strncmp (reg->name, name, len) == 0))
 148           return NUM_REGS + NUM_PSEUDO_REGS + nr;
 149       }
 150   }
 151
 152   return -1;
 153 }
 154
 155 static struct user_reg *
 156 usernum_to_user_reg (struct gdbarch *gdbarch, int usernum)
 157 {
 158   struct user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
 159   struct user_reg *reg;
 160   for (reg = regs->first; reg != NULL; reg = reg->next)
 161     {
 162       if (usernum == 0)
 163         return reg;
 164       usernum--;
 165     }
 166   return NULL;
 167 }
 168
 169 const char *
 170 user_reg_map_regnum_to_name (struct gdbarch *gdbarch, int regnum)
 171 {
 172   int maxregs = (gdbarch_num_regs (gdbarch)
 173                  + gdbarch_num_pseudo_regs (gdbarch));
 174   if (regnum < 0)
 175     return NULL;
 176   else if (regnum < maxregs)
 177     return gdbarch_register_name (gdbarch, regnum);
 178   else
 179     {
 180       struct user_reg *reg = usernum_to_user_reg (gdbarch, regnum - maxregs);
 181       if (reg == NULL)
 182         return NULL;
 183       else
 184         return reg->name;
 185     }
 186 }
 187
 188 struct value *
 189 value_of_user_reg (int regnum, struct frame_info *frame)
 190 {
 191   struct gdbarch *gdbarch = get_frame_arch (frame);
 192   int maxregs = (gdbarch_num_regs (gdbarch)
 193                  + gdbarch_num_pseudo_regs (gdbarch));
 194   struct user_reg *reg = usernum_to_user_reg (gdbarch, regnum - maxregs);
 195   gdb_assert (reg != NULL);
 196   return reg->read (frame);
 197 }
 198
 199 extern initialize_file_ftype _initialize_user_regs; /* -Wmissing-prototypes */
 200
 201 void
 202 _initialize_user_regs (void)
 203 {
 204   user_regs_data = register_gdbarch_data (user_regs_init);
 205 }