gdb/user-regs.c

   1 /* User visible, per-frame registers, for GDB, the GNU debugger.
   2
   3    Copyright (C) 2002, 2003, 2004 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., 51 Franklin Street, Fifth Floor,
  22    Boston, MA 02110-1301, 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 /* 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, 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->next = NULL;
  71   (*regs->last) = reg;
  72   regs->last = &(*regs->last)->next;
  73 }
  74
  75 /* An array of the builtin user registers.  */
  76
  77 static struct gdb_user_regs builtin_user_regs = { NULL, &builtin_user_regs.first };
  78
  79 void
  80 user_reg_add_builtin (const char *name, user_reg_read_ftype *read)
  81 {
  82   append_user_reg (&builtin_user_regs, name, read,
  83                    XMALLOC (struct user_reg));
  84 }
  85
  86 /* Per-architecture user registers.  Start with the builtin user
  87    registers and then, again, append.  */
  88
  89 static struct gdbarch_data *user_regs_data;
  90
  91 static void *
  92 user_regs_init (struct gdbarch *gdbarch)
  93 {
  94   struct user_reg *reg;
  95   struct gdb_user_regs *regs = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct gdb_user_regs);
  96   regs->last = &regs->first;
  97   for (reg = builtin_user_regs.first; reg != NULL; reg = reg->next)
  98     append_user_reg (regs, reg->name, reg->read,
  99                      GDBARCH_OBSTACK_ZALLOC (gdbarch, struct user_reg));
 100   return regs;
 101 }
 102
 103 void
 104 user_reg_add (struct gdbarch *gdbarch, const char *name,
 105                  user_reg_read_ftype *read)
 106 {
 107   struct gdb_user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
 108   if (regs == NULL)
 109     {
 110       /* ULGH, called during architecture initialization.  Patch
 111          things up.  */
 112       regs = user_regs_init (gdbarch);
 113       deprecated_set_gdbarch_data (gdbarch, user_regs_data, regs);
 114     }
 115   append_user_reg (regs, name, read,
 116                    GDBARCH_OBSTACK_ZALLOC (gdbarch, struct user_reg));
 117 }
 118
 119 int
 120 user_reg_map_name_to_regnum (struct gdbarch *gdbarch, const char *name,
 121                              int len)
 122 {
 123   /* Make life easy, set the len to something reasonable.  */
 124   if (len < 0)
 125     len = strlen (name);
 126
 127   /* Search register name space first - always let an architecture
 128      specific register override the user registers.  */
 129   {
 130     int i;
 131     int maxregs = (gdbarch_num_regs (gdbarch)
 132                    + gdbarch_num_pseudo_regs (gdbarch));
 133     for (i = 0; i < maxregs; i++)
 134       {
 135         const char *regname = gdbarch_register_name (gdbarch, i);
 136         if (regname != NULL && len == strlen (regname)
 137             && strncmp (regname, name, len) == 0)
 138           {
 139             return i;
 140           }
 141       }
 142   }
 143
 144   /* Search the user name space.  */
 145   {
 146     struct gdb_user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
 147     struct user_reg *reg;
 148     int nr;
 149     for (nr = 0, reg = regs->first; reg != NULL; reg = reg->next, nr++)
 150       {
 151         if ((len < 0 && strcmp (reg->name, name))
 152             || (len == strlen (reg->name)
 153                 && strncmp (reg->name, name, len) == 0))
 154           return NUM_REGS + NUM_PSEUDO_REGS + nr;
 155       }
 156   }
 157
 158   return -1;
 159 }
 160
 161 static struct user_reg *
 162 usernum_to_user_reg (struct gdbarch *gdbarch, int usernum)
 163 {
 164   struct gdb_user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
 165   struct user_reg *reg;
 166   for (reg = regs->first; reg != NULL; reg = reg->next)
 167     {
 168       if (usernum == 0)
 169         return reg;
 170       usernum--;
 171     }
 172   return NULL;
 173 }
 174
 175 const char *
 176 user_reg_map_regnum_to_name (struct gdbarch *gdbarch, int regnum)
 177 {
 178   int maxregs = (gdbarch_num_regs (gdbarch)
 179                  + gdbarch_num_pseudo_regs (gdbarch));
 180   if (regnum < 0)
 181     return NULL;
 182   else if (regnum < maxregs)
 183     return gdbarch_register_name (gdbarch, regnum);
 184   else
 185     {
 186       struct user_reg *reg = usernum_to_user_reg (gdbarch, regnum - maxregs);
 187       if (reg == NULL)
 188         return NULL;
 189       else
 190         return reg->name;
 191     }
 192 }
 193
 194 struct value *
 195 value_of_user_reg (int regnum, struct frame_info *frame)
 196 {
 197   struct gdbarch *gdbarch = get_frame_arch (frame);
 198   int maxregs = (gdbarch_num_regs (gdbarch)
 199                  + gdbarch_num_pseudo_regs (gdbarch));
 200   struct user_reg *reg = usernum_to_user_reg (gdbarch, regnum - maxregs);
 201   gdb_assert (reg != NULL);
 202   return reg->read (frame);
 203 }
 204
 205 extern initialize_file_ftype _initialize_user_regs; /* -Wmissing-prototypes */
 206
 207 void
 208 _initialize_user_regs (void)
 209 {
 210   user_regs_data = gdbarch_data_register_post_init (user_regs_init);
 211 }