gdb/user-regs.c

   1 /* User visible, per-frame registers, for GDB, the GNU debugger.
   2
   3    Copyright (C) 2002, 2003, 2004, 2007 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    .. gdbarch_num_regs + gdbarch_num_pseudo_regs)
  35    (which is controlled by the target).
  36    The target should never see a user register's regnum value.
  37
  38    Always append, never delete.  By doing this, the relative regnum
  39    (offset from gdbarch_num_regs + gdbarch_num_pseudo_regs)
  40     assigned to each user  register never changes.  */
  41
  42 struct user_reg
  43 {
  44   const char *name;
  45   struct value *(*read) (struct frame_info * frame, const void *baton);
  46   const void *baton;
  47   struct user_reg *next;
  48 };
  49
  50 /* This structure is named gdb_user_regs instead of user_regs to avoid
  51    conflicts with any "struct user_regs" in system headers.  For instance,
  52    on ARM GNU/Linux native builds, nm-linux.h includes <signal.h> includes
  53    <sys/ucontext.h> includes <sys/procfs.h> includes <sys/user.h>, which
  54    declares "struct user_regs".  */
  55
  56 struct gdb_user_regs
  57 {
  58   struct user_reg *first;
  59   struct user_reg **last;
  60 };
  61
  62 static void
  63 append_user_reg (struct gdb_user_regs *regs, const char *name,
  64                  user_reg_read_ftype *read, const void *baton,
  65                  struct user_reg *reg)
  66 {
  67   /* The caller is responsible for allocating memory needed to store
  68      the register.  By doing this, the function can operate on a
  69      register list stored in the common heap or a specific obstack.  */
  70   gdb_assert (reg != NULL);
  71   reg->name = name;
  72   reg->read = read;
  73   reg->baton = baton;
  74   reg->next = NULL;
  75   (*regs->last) = reg;
  76   regs->last = &(*regs->last)->next;
  77 }
  78
  79 /* An array of the builtin user registers.  */
  80
  81 static struct gdb_user_regs builtin_user_regs = { NULL, &builtin_user_regs.first };
  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                    XMALLOC (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 = GDBARCH_OBSTACK_ZALLOC (gdbarch, struct gdb_user_regs);
 101   regs->last = &regs->first;
 102   for (reg = builtin_user_regs.first; reg != NULL; reg = reg->next)
 103     append_user_reg (regs, reg->name, reg->read, reg->baton,
 104                      GDBARCH_OBSTACK_ZALLOC (gdbarch, struct user_reg));
 105   return regs;
 106 }
 107
 108 void
 109 user_reg_add (struct gdbarch *gdbarch, const char *name,
 110               user_reg_read_ftype *read, const void *baton)
 111 {
 112   struct gdb_user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
 113   if (regs == NULL)
 114     {
 115       /* ULGH, called during architecture initialization.  Patch
 116          things up.  */
 117       regs = user_regs_init (gdbarch);
 118       deprecated_set_gdbarch_data (gdbarch, user_regs_data, regs);
 119     }
 120   append_user_reg (regs, name, read, baton,
 121                    GDBARCH_OBSTACK_ZALLOC (gdbarch, struct user_reg));
 122 }
 123
 124 int
 125 user_reg_map_name_to_regnum (struct gdbarch *gdbarch, const char *name,
 126                              int len)
 127 {
 128   /* Make life easy, set the len to something reasonable.  */
 129   if (len < 0)
 130     len = strlen (name);
 131
 132   /* Search register name space first - always let an architecture
 133      specific register override the user registers.  */
 134   {
 135     int i;
 136     int maxregs = (gdbarch_num_regs (gdbarch)
 137                    + gdbarch_num_pseudo_regs (gdbarch));
 138     for (i = 0; i < maxregs; i++)
 139       {
 140         const char *regname = gdbarch_register_name (gdbarch, i);
 141         if (regname != NULL && len == strlen (regname)
 142             && strncmp (regname, name, len) == 0)
 143           {
 144             return i;
 145           }
 146       }
 147   }
 148
 149   /* Search the user name space.  */
 150   {
 151     struct gdb_user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
 152     struct user_reg *reg;
 153     int nr;
 154     for (nr = 0, reg = regs->first; reg != NULL; reg = reg->next, nr++)
 155       {
 156         if ((len < 0 && strcmp (reg->name, name))
 157             || (len == strlen (reg->name)
 158                 && strncmp (reg->name, name, len) == 0))
 159           return gdbarch_num_regs (current_gdbarch)
 160                  + gdbarch_num_pseudo_regs (current_gdbarch) + nr;
 161       }
 162   }
 163
 164   return -1;
 165 }
 166
 167 static struct user_reg *
 168 usernum_to_user_reg (struct gdbarch *gdbarch, int usernum)
 169 {
 170   struct gdb_user_regs *regs = gdbarch_data (gdbarch, user_regs_data);
 171   struct user_reg *reg;
 172   for (reg = regs->first; reg != NULL; reg = reg->next)
 173     {
 174       if (usernum == 0)
 175         return reg;
 176       usernum--;
 177     }
 178   return NULL;
 179 }
 180
 181 const char *
 182 user_reg_map_regnum_to_name (struct gdbarch *gdbarch, int regnum)
 183 {
 184   int maxregs = (gdbarch_num_regs (gdbarch)
 185                  + gdbarch_num_pseudo_regs (gdbarch));
 186   if (regnum < 0)
 187     return NULL;
 188   else if (regnum < maxregs)
 189     return gdbarch_register_name (gdbarch, regnum);
 190   else
 191     {
 192       struct user_reg *reg = usernum_to_user_reg (gdbarch, regnum - maxregs);
 193       if (reg == NULL)
 194         return NULL;
 195       else
 196         return reg->name;
 197     }
 198 }
 199
 200 struct value *
 201 value_of_user_reg (int regnum, struct frame_info *frame)
 202 {
 203   struct gdbarch *gdbarch = get_frame_arch (frame);
 204   int maxregs = (gdbarch_num_regs (gdbarch)
 205                  + gdbarch_num_pseudo_regs (gdbarch));
 206   struct user_reg *reg = usernum_to_user_reg (gdbarch, regnum - maxregs);
 207   gdb_assert (reg != NULL);
 208   return reg->read (frame, reg->baton);
 209 }
 210
 211 extern initialize_file_ftype _initialize_user_regs; /* -Wmissing-prototypes */
 212
 213 void
 214 _initialize_user_regs (void)
 215 {
 216   user_regs_data = gdbarch_data_register_post_init (user_regs_init);
 217 }