gdb/xml-tdesc.c

   1 /* XML target description support for GDB.
   2
   3    Copyright (C) 2006, 2008 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 3 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, see <http://www.gnu.org/licenses/>.  */
  21
  22 #include "defs.h"
  23 #include "gdbtypes.h"
  24 #include "target.h"
  25 #include "target-descriptions.h"
  26 #include "xml-support.h"
  27 #include "xml-tdesc.h"
  28
  29 #include "filenames.h"
  30
  31 #include "gdb_assert.h"
  32
  33 #if !defined(HAVE_LIBEXPAT)
  34
  35 /* Parse DOCUMENT into a target description.  Or don't, since we don't have
  36    an XML parser.  */
  37
  38 static struct target_desc *
  39 tdesc_parse_xml (const char *document, xml_fetch_another fetcher,
  40                  void *fetcher_baton)
  41 {
  42   static int have_warned;
  43
  44   if (!have_warned)
  45     {
  46       have_warned = 1;
  47       warning (_("Can not parse XML target description; XML support was "
  48                  "disabled at compile time"));
  49     }
  50
  51   return NULL;
  52 }
  53
  54 #else /* HAVE_LIBEXPAT */
  55
  56 /* A record of every XML description we have parsed.  We never discard
  57    old descriptions, because we never discard gdbarches.  As long as we
  58    have a gdbarch referencing this description, we want to have a copy
  59    of it here, so that if we parse the same XML document again we can
  60    return the same "struct target_desc *"; if they are not singletons,
  61    then we will create unnecessary duplicate gdbarches.  See
  62    gdbarch_list_lookup_by_info.  */
  63
  64 struct tdesc_xml_cache
  65 {
  66   const char *xml_document;
  67   struct target_desc *tdesc;
  68 };
  69 typedef struct tdesc_xml_cache tdesc_xml_cache_s;
  70 DEF_VEC_O(tdesc_xml_cache_s);
  71
  72 static VEC(tdesc_xml_cache_s) *xml_cache;
  73
  74 /* Callback data for target description parsing.  */
  75
  76 struct tdesc_parsing_data
  77 {
  78   /* The target description we are building.  */
  79   struct target_desc *tdesc;
  80
  81   /* The target feature we are currently parsing, or last parsed.  */
  82   struct tdesc_feature *current_feature;
  83
  84   /* The register number to use for the next register we see, if
  85      it does not have its own.  This starts at zero.  */
  86   int next_regnum;
  87
  88   /* The union we are currently parsing, or last parsed.  */
  89   struct type *current_union;
  90 };
  91
  92 /* Handle the end of an <architecture> element and its value.  */
  93
  94 static void
  95 tdesc_end_arch (struct gdb_xml_parser *parser,
  96                 const struct gdb_xml_element *element,
  97                 void *user_data, const char *body_text)
  98 {
  99   struct tdesc_parsing_data *data = user_data;
 100   const struct bfd_arch_info *arch;
 101
 102   arch = bfd_scan_arch (body_text);
 103   if (arch == NULL)
 104     gdb_xml_error (parser, _("Target description specified unknown "
 105                              "architecture \"%s\""), body_text);
 106   set_tdesc_architecture (data->tdesc, arch);
 107 }
 108
 109 /* Handle the start of a <target> element.  */
 110
 111 static void
 112 tdesc_start_target (struct gdb_xml_parser *parser,
 113                     const struct gdb_xml_element *element,
 114                     void *user_data, VEC(gdb_xml_value_s) *attributes)
 115 {
 116   struct tdesc_parsing_data *data = user_data;
 117   char *version = VEC_index (gdb_xml_value_s, attributes, 0)->value;
 118
 119   if (strcmp (version, "1.0") != 0)
 120     gdb_xml_error (parser,
 121                    _("Target description has unsupported version \"%s\""),
 122                    version);
 123 }
 124
 125 /* Handle the start of a <feature> element.  */
 126
 127 static void
 128 tdesc_start_feature (struct gdb_xml_parser *parser,
 129                      const struct gdb_xml_element *element,
 130                      void *user_data, VEC(gdb_xml_value_s) *attributes)
 131 {
 132   struct tdesc_parsing_data *data = user_data;
 133   char *name = VEC_index (gdb_xml_value_s, attributes, 0)->value;
 134
 135   data->current_feature = tdesc_create_feature (data->tdesc, name);
 136 }
 137
 138 /* Handle the start of a <reg> element.  Fill in the optional
 139    attributes and attach it to the containing feature.  */
 140
 141 static void
 142 tdesc_start_reg (struct gdb_xml_parser *parser,
 143                  const struct gdb_xml_element *element,
 144                  void *user_data, VEC(gdb_xml_value_s) *attributes)
 145 {
 146   struct tdesc_parsing_data *data = user_data;
 147   struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
 148   int ix = 0, length;
 149   char *name, *group, *type;
 150   int bitsize, regnum, save_restore;
 151
 152   length = VEC_length (gdb_xml_value_s, attributes);
 153
 154   name = attrs[ix++].value;
 155   bitsize = * (ULONGEST *) attrs[ix++].value;
 156
 157   if (ix < length && strcmp (attrs[ix].name, "regnum") == 0)
 158     regnum = * (ULONGEST *) attrs[ix++].value;
 159   else
 160     regnum = data->next_regnum;
 161
 162   if (ix < length && strcmp (attrs[ix].name, "type") == 0)
 163     type = attrs[ix++].value;
 164   else
 165     type = "int";
 166
 167   if (ix < length && strcmp (attrs[ix].name, "group") == 0)
 168     group = attrs[ix++].value;
 169   else
 170     group = NULL;
 171
 172   if (ix < length && strcmp (attrs[ix].name, "save-restore") == 0)
 173     save_restore = * (ULONGEST *) attrs[ix++].value;
 174   else
 175     save_restore = 1;
 176
 177   if (strcmp (type, "int") != 0
 178       && strcmp (type, "float") != 0
 179       && strcmp (type, "code_ptr") != 0
 180       && strcmp (type, "data_ptr") != 0
 181       && tdesc_named_type (data->current_feature, type) == NULL)
 182     gdb_xml_error (parser, _("Register \"%s\" has unknown type \"%s\""),
 183                    name, type);
 184
 185   tdesc_create_reg (data->current_feature, name, regnum, save_restore, group,
 186                     bitsize, type);
 187
 188   data->next_regnum = regnum + 1;
 189 }
 190
 191 /* Handle the start of a <union> element.  Initialize the type and
 192    record it with the current feature.  */
 193
 194 static void
 195 tdesc_start_union (struct gdb_xml_parser *parser,
 196                    const struct gdb_xml_element *element,
 197                    void *user_data, VEC(gdb_xml_value_s) *attributes)
 198 {
 199   struct tdesc_parsing_data *data = user_data;
 200   char *id = VEC_index (gdb_xml_value_s, attributes, 0)->value;
 201   struct type *type;
 202
 203   type = init_composite_type (NULL, TYPE_CODE_UNION);
 204   TYPE_NAME (type) = xstrdup (id);
 205   tdesc_record_type (data->current_feature, type);
 206   data->current_union = type;
 207 }
 208
 209 /* Handle the end of a <union> element.  */
 210
 211 static void
 212 tdesc_end_union (struct gdb_xml_parser *parser,
 213                  const struct gdb_xml_element *element,
 214                  void *user_data, const char *body_text)
 215 {
 216   struct tdesc_parsing_data *data = user_data;
 217   int i;
 218
 219   /* If any of the children of this union are vectors, flag the union
 220      as a vector also.  This allows e.g. a union of two vector types
 221      to show up automatically in "info vector".  */
 222   for (i = 0; i < TYPE_NFIELDS (data->current_union); i++)
 223     if (TYPE_VECTOR (TYPE_FIELD_TYPE (data->current_union, i)))
 224       {
 225         TYPE_VECTOR (data->current_union) = 1;
 226         break;
 227       }
 228 }
 229
 230 /* Handle the start of a <field> element.  Attach the field to the
 231    current union.  */
 232
 233 static void
 234 tdesc_start_field (struct gdb_xml_parser *parser,
 235                    const struct gdb_xml_element *element,
 236                    void *user_data, VEC(gdb_xml_value_s) *attributes)
 237 {
 238   struct tdesc_parsing_data *data = user_data;
 239   struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
 240   struct type *type, *field_type;
 241   char *field_name, *field_type_id;
 242
 243   field_name = attrs[0].value;
 244   field_type_id = attrs[1].value;
 245
 246   field_type = tdesc_named_type (data->current_feature, field_type_id);
 247   if (field_type == NULL)
 248     gdb_xml_error (parser, _("Union field \"%s\" references undefined "
 249                              "type \"%s\""),
 250                    field_name, field_type_id);
 251
 252   append_composite_type_field (data->current_union, xstrdup (field_name),
 253                                field_type);
 254 }
 255
 256 /* Handle the start of a <vector> element.  Initialize the type and
 257    record it with the current feature.  */
 258
 259 static void
 260 tdesc_start_vector (struct gdb_xml_parser *parser,
 261                     const struct gdb_xml_element *element,
 262                     void *user_data, VEC(gdb_xml_value_s) *attributes)
 263 {
 264   struct tdesc_parsing_data *data = user_data;
 265   struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
 266   struct type *type, *field_type, *range_type;
 267   char *id, *field_type_id;
 268   int count;
 269
 270   id = attrs[0].value;
 271   field_type_id = attrs[1].value;
 272   count = * (ULONGEST *) attrs[2].value;
 273
 274   field_type = tdesc_named_type (data->current_feature, field_type_id);
 275   if (field_type == NULL)
 276     gdb_xml_error (parser, _("Vector \"%s\" references undefined type \"%s\""),
 277                    id, field_type_id);
 278
 279   type = init_vector_type (field_type, count);
 280   TYPE_NAME (type) = xstrdup (id);
 281
 282   tdesc_record_type (data->current_feature, type);
 283 }
 284
 285 /* The elements and attributes of an XML target description.  */
 286
 287 static const struct gdb_xml_attribute field_attributes[] = {
 288   { "name", GDB_XML_AF_NONE, NULL, NULL },
 289   { "type", GDB_XML_AF_NONE, NULL, NULL },
 290   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 291 };
 292
 293 static const struct gdb_xml_element union_children[] = {
 294   { "field", field_attributes, NULL, GDB_XML_EF_REPEATABLE,
 295     tdesc_start_field, NULL },
 296   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 297 };
 298
 299 static const struct gdb_xml_attribute reg_attributes[] = {
 300   { "name", GDB_XML_AF_NONE, NULL, NULL },
 301   { "bitsize", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 302   { "regnum", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },
 303   { "type", GDB_XML_AF_OPTIONAL, NULL, NULL },
 304   { "group", GDB_XML_AF_OPTIONAL, NULL, NULL },
 305   { "save-restore", GDB_XML_AF_OPTIONAL,
 306     gdb_xml_parse_attr_enum, gdb_xml_enums_boolean },
 307   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 308 };
 309
 310 static const struct gdb_xml_attribute union_attributes[] = {
 311   { "id", GDB_XML_AF_NONE, NULL, NULL },
 312   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 313 };
 314
 315 static const struct gdb_xml_attribute vector_attributes[] = {
 316   { "id", GDB_XML_AF_NONE, NULL, NULL },
 317   { "type", GDB_XML_AF_NONE, NULL, NULL },
 318   { "count", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 319   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 320 };
 321
 322 static const struct gdb_xml_attribute feature_attributes[] = {
 323   { "name", GDB_XML_AF_NONE, NULL, NULL },
 324   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 325 };
 326
 327 static const struct gdb_xml_element feature_children[] = {
 328   { "reg", reg_attributes, NULL,
 329     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 330     tdesc_start_reg, NULL },
 331   { "union", union_attributes, union_children,
 332     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 333     tdesc_start_union, tdesc_end_union },
 334   { "vector", vector_attributes, NULL,
 335     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 336     tdesc_start_vector, NULL },
 337   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 338 };
 339
 340 static const struct gdb_xml_attribute target_attributes[] = {
 341   { "version", GDB_XML_AF_NONE, NULL, NULL },
 342   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 343 };
 344
 345 static const struct gdb_xml_element target_children[] = {
 346   { "architecture", NULL, NULL, GDB_XML_EF_OPTIONAL,
 347     NULL, tdesc_end_arch },
 348   { "feature", feature_attributes, feature_children,
 349     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 350     tdesc_start_feature, NULL },
 351   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 352 };
 353
 354 static const struct gdb_xml_element tdesc_elements[] = {
 355   { "target", target_attributes, target_children, GDB_XML_EF_NONE,
 356     tdesc_start_target, NULL },
 357   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 358 };
 359
 360 /* Parse DOCUMENT into a target description and return it.  */
 361
 362 static struct target_desc *
 363 tdesc_parse_xml (const char *document, xml_fetch_another fetcher,
 364                  void *fetcher_baton)
 365 {
 366   struct cleanup *back_to, *result_cleanup;
 367   struct gdb_xml_parser *parser;
 368   struct tdesc_parsing_data data;
 369   struct tdesc_xml_cache *cache;
 370   char *expanded_text;
 371   int ix;
 372
 373   /* Expand all XInclude directives.  */
 374   expanded_text = xml_process_xincludes (_("target description"),
 375                                          document, fetcher, fetcher_baton, 0);
 376   if (expanded_text == NULL)
 377     {
 378       warning (_("Could not load XML target description; ignoring"));
 379       return NULL;
 380     }
 381
 382   /* Check for an exact match in the list of descriptions we have
 383      previously parsed.  strcmp is a slightly inefficient way to
 384      do this; an SHA-1 checksum would work as well.  */
 385   for (ix = 0; VEC_iterate (tdesc_xml_cache_s, xml_cache, ix, cache); ix++)
 386     if (strcmp (cache->xml_document, expanded_text) == 0)
 387       {
 388        xfree (expanded_text);
 389        return cache->tdesc;
 390       }
 391
 392   back_to = make_cleanup (null_cleanup, NULL);
 393   parser = gdb_xml_create_parser_and_cleanup (_("target description"),
 394                                               tdesc_elements, &data);
 395   gdb_xml_use_dtd (parser, "gdb-target.dtd");
 396
 397   memset (&data, 0, sizeof (struct tdesc_parsing_data));
 398   data.tdesc = allocate_target_description ();
 399   result_cleanup = make_cleanup_free_target_description (data.tdesc);
 400   make_cleanup (xfree, expanded_text);
 401
 402   if (gdb_xml_parse (parser, expanded_text) == 0)
 403     {
 404       /* Parsed successfully.  */
 405       struct tdesc_xml_cache new_cache;
 406
 407       new_cache.xml_document = expanded_text;
 408       new_cache.tdesc = data.tdesc;
 409       VEC_safe_push (tdesc_xml_cache_s, xml_cache, &new_cache);
 410       discard_cleanups (result_cleanup);
 411       do_cleanups (back_to);
 412       return data.tdesc;
 413     }
 414   else
 415     {
 416       warning (_("Could not load XML target description; ignoring"));
 417       do_cleanups (back_to);
 418       return NULL;
 419     }
 420 }
 421 #endif /* HAVE_LIBEXPAT */
 422 \f
 423
 424 /* Open FILENAME, read all its text into memory, close it, and return
 425    the text.  If something goes wrong, return NULL and warn.  */
 426
 427 static char *
 428 fetch_xml_from_file (const char *filename, void *baton)
 429 {
 430   const char *dirname = baton;
 431   FILE *file;
 432   struct cleanup *back_to;
 433   char *text;
 434   size_t len, offset;
 435
 436   if (dirname && *dirname)
 437     {
 438       char *fullname = concat (dirname, "/", filename, (char *) NULL);
 439       if (fullname == NULL)
 440         nomem (0);
 441       file = fopen (fullname, FOPEN_RT);
 442       xfree (fullname);
 443     }
 444   else
 445     file = fopen (filename, FOPEN_RT);
 446
 447   if (file == NULL)
 448     return NULL;
 449
 450   back_to = make_cleanup_fclose (file);
 451
 452   /* Read in the whole file, one chunk at a time.  */
 453   len = 4096;
 454   offset = 0;
 455   text = xmalloc (len);
 456   make_cleanup (free_current_contents, &text);
 457   while (1)
 458     {
 459       size_t bytes_read;
 460
 461       /* Continue reading where the last read left off.  Leave at least
 462          one byte so that we can NUL-terminate the result.  */
 463       bytes_read = fread (text + offset, 1, len - offset - 1, file);
 464       if (ferror (file))
 465         {
 466           warning (_("Read error from \"%s\""), filename);
 467           do_cleanups (back_to);
 468           return NULL;
 469         }
 470
 471       offset += bytes_read;
 472
 473       if (feof (file))
 474         break;
 475
 476       len = len * 2;
 477       text = xrealloc (text, len);
 478     }
 479
 480   fclose (file);
 481   discard_cleanups (back_to);
 482
 483   text[offset] = '\0';
 484   return text;
 485 }
 486
 487 /* Read an XML target description from FILENAME.  Parse it, and return
 488    the parsed description.  */
 489
 490 const struct target_desc *
 491 file_read_description_xml (const char *filename)
 492 {
 493   struct target_desc *tdesc;
 494   char *tdesc_str;
 495   struct cleanup *back_to;
 496   char *dirname;
 497
 498   tdesc_str = fetch_xml_from_file (filename, NULL);
 499   if (tdesc_str == NULL)
 500     {
 501       warning (_("Could not open \"%s\""), filename);
 502       return NULL;
 503     }
 504
 505   back_to = make_cleanup (xfree, tdesc_str);
 506
 507   dirname = ldirname (filename);
 508   if (dirname != NULL)
 509     make_cleanup (xfree, dirname);
 510
 511   tdesc = tdesc_parse_xml (tdesc_str, fetch_xml_from_file, dirname);
 512   do_cleanups (back_to);
 513
 514   return tdesc;
 515 }
 516
 517 /* Read a string representation of available features from the target,
 518    using TARGET_OBJECT_AVAILABLE_FEATURES.  The returned string is
 519    malloc allocated and NUL-terminated.  NAME should be a non-NULL
 520    string identifying the XML document we want; the top level document
 521    is "target.xml".  Other calls may be performed for the DTD or
 522    for <xi:include>.  */
 523
 524 static char *
 525 fetch_available_features_from_target (const char *name, void *baton_)
 526 {
 527   struct target_ops *ops = baton_;
 528
 529   /* Read this object as a string.  This ensures that a NUL
 530      terminator is added.  */
 531   return target_read_stralloc (ops,
 532                                TARGET_OBJECT_AVAILABLE_FEATURES,
 533                                name);
 534 }
 535 \f
 536
 537 /* Read an XML target description using OPS.  Parse it, and return the
 538    parsed description.  */
 539
 540 const struct target_desc *
 541 target_read_description_xml (struct target_ops *ops)
 542 {
 543   struct target_desc *tdesc;
 544   char *tdesc_str;
 545   struct cleanup *back_to;
 546
 547   tdesc_str = fetch_available_features_from_target ("target.xml", ops);
 548   if (tdesc_str == NULL)
 549     return NULL;
 550
 551   back_to = make_cleanup (xfree, tdesc_str);
 552   tdesc = tdesc_parse_xml (tdesc_str,
 553                            fetch_available_features_from_target,
 554                            ops);
 555   do_cleanups (back_to);
 556
 557   return tdesc;
 558 }