gdb/target-descriptions.c

   1 /* Target description support for GDB.
   2
   3    Copyright (C) 2006, 2007 Free Software Foundation, Inc.
   4
   5    Contributed by CodeSourcery.
   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 "arch-utils.h"
  26 #include "gdbcmd.h"
  27 #include "target.h"
  28 #include "target-descriptions.h"
  29 #include "vec.h"
  30 #include "xml-tdesc.h"
  31
  32 #include "gdb_assert.h"
  33
  34 /* Types.  */
  35
  36 typedef struct property
  37 {
  38   char *key;
  39   char *value;
  40 } property_s;
  41 DEF_VEC_O(property_s);
  42
  43 struct target_desc
  44 {
  45   /* The architecture reported by the target, if any.  */
  46   const struct bfd_arch_info *arch;
  47
  48   /* Any architecture-specific properties specified by the target.  */
  49   VEC(property_s) *properties;
  50 };
  51
  52 /* Global state.  These variables are associated with the current
  53    target; if GDB adds support for multiple simultaneous targets, then
  54    these variables should become target-specific data.  */
  55
  56 /* A flag indicating that a description has already been fetched from
  57    the current target, so it should not be queried again.  */
  58
  59 static int target_desc_fetched;
  60
  61 /* The description fetched from the current target, or NULL if the
  62    current target did not supply any description.  Only valid when
  63    target_desc_fetched is set.  Only the description initialization
  64    code should access this; normally, the description should be
  65    accessed through the gdbarch object.  */
  66
  67 static const struct target_desc *current_target_desc;
  68
  69 /* Other global variables.  */
  70
  71 /* The filename to read a target description from.  */
  72
  73 static char *target_description_filename;
  74
  75 /* Fetch the current target's description, and switch the current
  76    architecture to one which incorporates that description.  */
  77
  78 void
  79 target_find_description (void)
  80 {
  81   /* If we've already fetched a description from the target, don't do
  82      it again.  This allows a target to fetch the description early,
  83      during its to_open or to_create_inferior, if it needs extra
  84      information about the target to initialize.  */
  85   if (target_desc_fetched)
  86     return;
  87
  88   /* The current architecture should not have any target description
  89      specified.  It should have been cleared, e.g. when we
  90      disconnected from the previous target.  */
  91   gdb_assert (gdbarch_target_desc (current_gdbarch) == NULL);
  92
  93   /* First try to fetch an XML description from the user-specified
  94      file.  */
  95   current_target_desc = NULL;
  96   if (target_description_filename != NULL
  97       && *target_description_filename != '\0')
  98     current_target_desc
  99       = file_read_description_xml (target_description_filename);
 100
 101   /* Next try to read the description from the current target using
 102      target objects.  */
 103   if (current_target_desc == NULL)
 104     current_target_desc = target_read_description_xml (&current_target);
 105
 106   /* If that failed try a target-specific hook.  */
 107   if (current_target_desc == NULL)
 108     current_target_desc = target_read_description (&current_target);
 109
 110   /* If a non-NULL description was returned, then update the current
 111      architecture.  */
 112   if (current_target_desc)
 113     {
 114       struct gdbarch_info info;
 115
 116       gdbarch_info_init (&info);
 117       info.target_desc = current_target_desc;
 118       if (!gdbarch_update_p (info))
 119         warning (_("Could not use target-supplied description"));
 120     }
 121
 122   /* Now that we know this description is usable, record that we
 123      fetched it.  */
 124   target_desc_fetched = 1;
 125 }
 126
 127 /* Discard any description fetched from the current target, and switch
 128    the current architecture to one with no target description.  */
 129
 130 void
 131 target_clear_description (void)
 132 {
 133   struct gdbarch_info info;
 134
 135   if (!target_desc_fetched)
 136     return;
 137
 138   target_desc_fetched = 0;
 139   current_target_desc = NULL;
 140
 141   gdbarch_info_init (&info);
 142   if (!gdbarch_update_p (info))
 143     internal_error (__FILE__, __LINE__,
 144                     _("Could not remove target-supplied description"));
 145 }
 146
 147 /* Return the global current target description.  This should only be
 148    used by gdbarch initialization code; most access should be through
 149    an existing gdbarch.  */
 150
 151 const struct target_desc *
 152 target_current_description (void)
 153 {
 154   if (target_desc_fetched)
 155     return current_target_desc;
 156
 157   return NULL;
 158 }
 159 \f
 160
 161 /* Direct accessors for feature sets.  */
 162
 163 /* Return the string value of a property named KEY, or NULL if the
 164    property was not specified.  */
 165
 166 const char *
 167 tdesc_property (const struct target_desc *target_desc, const char *key)
 168 {
 169   struct property *prop;
 170   int ix;
 171
 172   for (ix = 0; VEC_iterate (property_s, target_desc->properties, ix, prop);
 173        ix++)
 174     if (strcmp (prop->key, key) == 0)
 175       return prop->value;
 176
 177   return NULL;
 178 }
 179
 180 /* Return the BFD architecture associated with this target
 181    description, or NULL if no architecture was specified.  */
 182
 183 const struct bfd_arch_info *
 184 tdesc_architecture (const struct target_desc *target_desc)
 185 {
 186   return target_desc->arch;
 187 }
 188 \f
 189
 190 /* Methods for constructing a target description.  */
 191
 192 struct target_desc *
 193 allocate_target_description (void)
 194 {
 195   return XZALLOC (struct target_desc);
 196 }
 197
 198 static void
 199 free_target_description (void *arg)
 200 {
 201   struct target_desc *target_desc = arg;
 202   struct property *prop;
 203   int ix;
 204
 205   for (ix = 0;
 206        VEC_iterate (property_s, target_desc->properties, ix, prop);
 207        ix++)
 208     {
 209       xfree (prop->key);
 210       xfree (prop->value);
 211     }
 212   VEC_free (property_s, target_desc->properties);
 213
 214   xfree (target_desc);
 215 }
 216
 217 struct cleanup *
 218 make_cleanup_free_target_description (struct target_desc *target_desc)
 219 {
 220   return make_cleanup (free_target_description, target_desc);
 221 }
 222
 223 void
 224 set_tdesc_property (struct target_desc *target_desc,
 225                     const char *key, const char *value)
 226 {
 227   struct property *prop, new_prop;
 228   int ix;
 229
 230   gdb_assert (key != NULL && value != NULL);
 231
 232   for (ix = 0; VEC_iterate (property_s, target_desc->properties, ix, prop);
 233        ix++)
 234     if (strcmp (prop->key, key) == 0)
 235       internal_error (__FILE__, __LINE__,
 236                       _("Attempted to add duplicate property \"%s\""), key);
 237
 238   new_prop.key = xstrdup (key);
 239   new_prop.value = xstrdup (value);
 240   VEC_safe_push (property_s, target_desc->properties, &new_prop);
 241 }
 242
 243 void
 244 set_tdesc_architecture (struct target_desc *target_desc,
 245                         const struct bfd_arch_info *arch)
 246 {
 247   target_desc->arch = arch;
 248 }
 249 \f
 250
 251 static struct cmd_list_element *tdesc_set_cmdlist, *tdesc_show_cmdlist;
 252 static struct cmd_list_element *tdesc_unset_cmdlist;
 253
 254 /* Helper functions for the CLI commands.  */
 255
 256 static void
 257 set_tdesc_cmd (char *args, int from_tty)
 258 {
 259   help_list (tdesc_set_cmdlist, "set tdesc ", -1, gdb_stdout);
 260 }
 261
 262 static void
 263 show_tdesc_cmd (char *args, int from_tty)
 264 {
 265   cmd_show_list (tdesc_show_cmdlist, from_tty, "");
 266 }
 267
 268 static void
 269 unset_tdesc_cmd (char *args, int from_tty)
 270 {
 271   help_list (tdesc_unset_cmdlist, "unset tdesc ", -1, gdb_stdout);
 272 }
 273
 274 static void
 275 set_tdesc_filename_cmd (char *args, int from_tty,
 276                         struct cmd_list_element *c)
 277 {
 278   target_clear_description ();
 279   target_find_description ();
 280 }
 281
 282 static void
 283 show_tdesc_filename_cmd (struct ui_file *file, int from_tty,
 284                          struct cmd_list_element *c,
 285                          const char *value)
 286 {
 287   if (value != NULL && *value != '\0')
 288     printf_filtered (_("\
 289 The target description will be read from \"%s\".\n"),
 290                      value);
 291   else
 292     printf_filtered (_("\
 293 The target description will be read from the target.\n"));
 294 }
 295
 296 static void
 297 unset_tdesc_filename_cmd (char *args, int from_tty)
 298 {
 299   xfree (target_description_filename);
 300   target_description_filename = NULL;
 301   target_clear_description ();
 302   target_find_description ();
 303 }
 304
 305 void
 306 _initialize_target_descriptions (void)
 307 {
 308   add_prefix_cmd ("tdesc", class_maintenance, set_tdesc_cmd, _("\
 309 Set target description specific variables."),
 310                   &tdesc_set_cmdlist, "set tdesc ",
 311                   0 /* allow-unknown */, &setlist);
 312   add_prefix_cmd ("tdesc", class_maintenance, show_tdesc_cmd, _("\
 313 Show target description specific variables."),
 314                   &tdesc_show_cmdlist, "show tdesc ",
 315                   0 /* allow-unknown */, &showlist);
 316   add_prefix_cmd ("tdesc", class_maintenance, unset_tdesc_cmd, _("\
 317 Unset target description specific variables."),
 318                   &tdesc_unset_cmdlist, "unset tdesc ",
 319                   0 /* allow-unknown */, &unsetlist);
 320
 321   add_setshow_filename_cmd ("filename", class_obscure,
 322                             &target_description_filename,
 323                             _("\
 324 Set the file to read for an XML target description"), _("\
 325 Show the file to read for an XML target description"), _("\
 326 When set, GDB will read the target description from a local\n\
 327 file instead of querying the remote target."),
 328                             set_tdesc_filename_cmd,
 329                             show_tdesc_filename_cmd,
 330                             &tdesc_set_cmdlist, &tdesc_show_cmdlist);
 331
 332   add_cmd ("filename", class_obscure, unset_tdesc_filename_cmd, _("\
 333 Unset the file to read for an XML target description.  When unset,\n\
 334 GDB will read the description from the target."),
 335            &tdesc_unset_cmdlist);
 336 }