gdb/xml-tdesc.c

   1 /* XML target description support for GDB.
   2
   3    Copyright (C) 2006
   4    Free Software Foundation, Inc.
   5
   6    Contributed by CodeSourcery.
   7
   8    This file is part of GDB.
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 3 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  22
  23 #include "defs.h"
  24 #include "gdbtypes.h"
  25 #include "target.h"
  26 #include "target-descriptions.h"
  27 #include "xml-support.h"
  28 #include "xml-tdesc.h"
  29
  30 #include "filenames.h"
  31
  32 #include "gdb_assert.h"
  33
  34 #if !defined(HAVE_LIBEXPAT)
  35
  36 /* Parse DOCUMENT into a target description.  Or don't, since we don't have
  37    an XML parser.  */
  38
  39 static struct target_desc *
  40 tdesc_parse_xml (const char *document, xml_fetch_another fetcher,
  41                  void *fetcher_baton)
  42 {
  43   static int have_warned;
  44
  45   if (!have_warned)
  46     {
  47       have_warned = 1;
  48       warning (_("Can not parse XML target description; XML support was "
  49                  "disabled at compile time"));
  50     }
  51
  52   return NULL;
  53 }
  54
  55 #else /* HAVE_LIBEXPAT */
  56
  57 /* A record of every XML description we have parsed.  We never discard
  58    old descriptions, because we never discard gdbarches.  As long as we
  59    have a gdbarch referencing this description, we want to have a copy
  60    of it here, so that if we parse the same XML document again we can
  61    return the same "struct target_desc *"; if they are not singletons,
  62    then we will create unnecessary duplicate gdbarches.  See
  63    gdbarch_list_lookup_by_info.  */
  64
  65 struct tdesc_xml_cache
  66 {
  67   const char *xml_document;
  68   struct target_desc *tdesc;
  69 };
  70 typedef struct tdesc_xml_cache tdesc_xml_cache_s;
  71 DEF_VEC_O(tdesc_xml_cache_s);
  72
  73 static VEC(tdesc_xml_cache_s) *xml_cache;
  74
  75 /* Callback data for target description parsing.  */
  76
  77 struct tdesc_parsing_data
  78 {
  79   /* The target description we are building.  */
  80   struct target_desc *tdesc;
  81
  82   /* The target feature we are currently parsing, or last parsed.  */
  83   struct tdesc_feature *current_feature;
  84
  85   /* The register number to use for the next register we see, if
  86      it does not have its own.  This starts at zero.  */
  87   int next_regnum;
  88
  89   /* The union we are currently parsing, or last parsed.  */
  90   struct type *current_union;
  91 };
  92
  93 /* Handle the end of an <architecture> element and its value.  */
  94
  95 static void
  96 tdesc_end_arch (struct gdb_xml_parser *parser,
  97                 const struct gdb_xml_element *element,
  98                 void *user_data, const char *body_text)
  99 {
 100   struct tdesc_parsing_data *data = user_data;
 101   const struct bfd_arch_info *arch;
 102
 103   arch = bfd_scan_arch (body_text);
 104   if (arch == NULL)
 105     gdb_xml_error (parser, _("Target description specified unknown "
 106                              "architecture \"%s\""), body_text);
 107   set_tdesc_architecture (data->tdesc, arch);
 108 }
 109
 110 /* Handle the start of a <target> element.  */
 111
 112 static void
 113 tdesc_start_target (struct gdb_xml_parser *parser,
 114                     const struct gdb_xml_element *element,
 115                     void *user_data, VEC(gdb_xml_value_s) *attributes)
 116 {
 117   struct tdesc_parsing_data *data = user_data;
 118   char *version = VEC_index (gdb_xml_value_s, attributes, 0)->value;
 119
 120   if (strcmp (version, "1.0") != 0)
 121     gdb_xml_error (parser,
 122                    _("Target description has unsupported version \"%s\""),
 123                    version);
 124 }
 125
 126 /* Handle the start of a <feature> element.  */
 127
 128 static void
 129 tdesc_start_feature (struct gdb_xml_parser *parser,
 130                      const struct gdb_xml_element *element,
 131                      void *user_data, VEC(gdb_xml_value_s) *attributes)
 132 {
 133   struct tdesc_parsing_data *data = user_data;
 134   char *name = VEC_index (gdb_xml_value_s, attributes, 0)->value;
 135
 136   data->current_feature = tdesc_create_feature (data->tdesc, name);
 137 }
 138
 139 /* Handle the start of a <reg> element.  Fill in the optional
 140    attributes and attach it to the containing feature.  */
 141
 142 static void
 143 tdesc_start_reg (struct gdb_xml_parser *parser,
 144                  const struct gdb_xml_element *element,
 145                  void *user_data, VEC(gdb_xml_value_s) *attributes)
 146 {
 147   struct tdesc_parsing_data *data = user_data;
 148   struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
 149   int ix = 0, length;
 150   char *name, *group, *type;
 151   int bitsize, regnum, save_restore;
 152
 153   length = VEC_length (gdb_xml_value_s, attributes);
 154
 155   name = attrs[ix++].value;
 156   bitsize = * (ULONGEST *) attrs[ix++].value;
 157
 158   if (ix < length && strcmp (attrs[ix].name, "regnum") == 0)
 159     regnum = * (ULONGEST *) attrs[ix++].value;
 160   else
 161     regnum = data->next_regnum;
 162
 163   if (ix < length && strcmp (attrs[ix].name, "type") == 0)
 164     type = attrs[ix++].value;
 165   else
 166     type = "int";
 167
 168   if (ix < length && strcmp (attrs[ix].name, "group") == 0)
 169     group = attrs[ix++].value;
 170   else
 171     group = NULL;
 172
 173   if (ix < length && strcmp (attrs[ix].name, "save-restore") == 0)
 174     save_restore = * (ULONGEST *) attrs[ix++].value;
 175   else
 176     save_restore = 1;
 177
 178   if (strcmp (type, "int") != 0
 179       && strcmp (type, "float") != 0
 180       && strcmp (type, "code_ptr") != 0
 181       && strcmp (type, "data_ptr") != 0
 182       && tdesc_named_type (data->current_feature, type) == NULL)
 183     gdb_xml_error (parser, _("Register \"%s\" has unknown type \"%s\""),
 184                    name, type);
 185
 186   tdesc_create_reg (data->current_feature, name, regnum, save_restore, group,
 187                     bitsize, type);
 188
 189   data->next_regnum = regnum + 1;
 190 }
 191
 192 /* Handle the start of a <union> element.  Initialize the type and
 193    record it with the current feature.  */
 194
 195 static void
 196 tdesc_start_union (struct gdb_xml_parser *parser,
 197                    const struct gdb_xml_element *element,
 198                    void *user_data, VEC(gdb_xml_value_s) *attributes)
 199 {
 200   struct tdesc_parsing_data *data = user_data;
 201   char *id = VEC_index (gdb_xml_value_s, attributes, 0)->value;
 202   struct type *type;
 203
 204   type = init_composite_type (NULL, TYPE_CODE_UNION);
 205   TYPE_NAME (type) = xstrdup (id);
 206   tdesc_record_type (data->current_feature, type);
 207   data->current_union = type;
 208 }
 209
 210 /* Handle the end of a <union> element.  */
 211
 212 static void
 213 tdesc_end_union (struct gdb_xml_parser *parser,
 214                  const struct gdb_xml_element *element,
 215                  void *user_data, const char *body_text)
 216 {
 217   struct tdesc_parsing_data *data = user_data;
 218   int i;
 219
 220   /* If any of the children of this union are vectors, flag the union
 221      as a vector also.  This allows e.g. a union of two vector types
 222      to show up automatically in "info vector".  */
 223   for (i = 0; i < TYPE_NFIELDS (data->current_union); i++)
 224     if (TYPE_VECTOR (TYPE_FIELD_TYPE (data->current_union, i)))
 225       {
 226         TYPE_FLAGS (data->current_union) |= TYPE_FLAG_VECTOR;
 227         break;
 228       }
 229 }
 230
 231 /* Handle the start of a <field> element.  Attach the field to the
 232    current union.  */
 233
 234 static void
 235 tdesc_start_field (struct gdb_xml_parser *parser,
 236                    const struct gdb_xml_element *element,
 237                    void *user_data, VEC(gdb_xml_value_s) *attributes)
 238 {
 239   struct tdesc_parsing_data *data = user_data;
 240   struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
 241   struct type *type, *field_type;
 242   char *field_name, *field_type_id;
 243
 244   field_name = attrs[0].value;
 245   field_type_id = attrs[1].value;
 246
 247   field_type = tdesc_named_type (data->current_feature, field_type_id);
 248   if (field_type == NULL)
 249     gdb_xml_error (parser, _("Union field \"%s\" references undefined "
 250                              "type \"%s\""),
 251                    field_name, field_type_id);
 252
 253   append_composite_type_field (data->current_union, xstrdup (field_name),
 254                                field_type);
 255 }
 256
 257 /* Handle the start of a <vector> element.  Initialize the type and
 258    record it with the current feature.  */
 259
 260 static void
 261 tdesc_start_vector (struct gdb_xml_parser *parser,
 262                     const struct gdb_xml_element *element,
 263                     void *user_data, VEC(gdb_xml_value_s) *attributes)
 264 {
 265   struct tdesc_parsing_data *data = user_data;
 266   struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
 267   struct type *type, *field_type, *range_type;
 268   char *id, *field_type_id;
 269   int count;
 270
 271   id = attrs[0].value;
 272   field_type_id = attrs[1].value;
 273   count = * (ULONGEST *) attrs[2].value;
 274
 275   field_type = tdesc_named_type (data->current_feature, field_type_id);
 276   if (field_type == NULL)
 277     gdb_xml_error (parser, _("Vector \"%s\" references undefined type \"%s\""),
 278                    id, field_type_id);
 279
 280   /* A vector is just an array plus a special flag.  */
 281   range_type = create_range_type (NULL, builtin_type_int, 0, count - 1);
 282   type = create_array_type (NULL, field_type, range_type);
 283   TYPE_NAME (type) = xstrdup (id);
 284
 285   TYPE_FLAGS (type) |= TYPE_FLAG_VECTOR;
 286
 287   tdesc_record_type (data->current_feature, type);
 288 }
 289
 290 /* The elements and attributes of an XML target description.  */
 291
 292 static const struct gdb_xml_attribute field_attributes[] = {
 293   { "name", GDB_XML_AF_NONE, NULL, NULL },
 294   { "type", GDB_XML_AF_NONE, NULL, NULL },
 295   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 296 };
 297
 298 static const struct gdb_xml_element union_children[] = {
 299   { "field", field_attributes, NULL, GDB_XML_EF_REPEATABLE,
 300     tdesc_start_field, NULL },
 301   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 302 };
 303
 304 static const struct gdb_xml_attribute reg_attributes[] = {
 305   { "name", GDB_XML_AF_NONE, NULL, NULL },
 306   { "bitsize", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 307   { "regnum", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },
 308   { "type", GDB_XML_AF_OPTIONAL, NULL, NULL },
 309   { "group", GDB_XML_AF_OPTIONAL, NULL, NULL },
 310   { "save-restore", GDB_XML_AF_OPTIONAL,
 311     gdb_xml_parse_attr_enum, gdb_xml_enums_boolean },
 312   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 313 };
 314
 315 static const struct gdb_xml_attribute union_attributes[] = {
 316   { "id", GDB_XML_AF_NONE, NULL, NULL },
 317   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 318 };
 319
 320 static const struct gdb_xml_attribute vector_attributes[] = {
 321   { "id", GDB_XML_AF_NONE, NULL, NULL },
 322   { "type", GDB_XML_AF_NONE, NULL, NULL },
 323   { "count", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 324   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 325 };
 326
 327 static const struct gdb_xml_attribute feature_attributes[] = {
 328   { "name", GDB_XML_AF_NONE, NULL, NULL },
 329   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 330 };
 331
 332 static const struct gdb_xml_element feature_children[] = {
 333   { "reg", reg_attributes, NULL,
 334     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 335     tdesc_start_reg, NULL },
 336   { "union", union_attributes, union_children,
 337     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 338     tdesc_start_union, tdesc_end_union },
 339   { "vector", vector_attributes, NULL,
 340     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 341     tdesc_start_vector, NULL },
 342   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 343 };
 344
 345 static const struct gdb_xml_attribute target_attributes[] = {
 346   { "version", GDB_XML_AF_NONE, NULL, NULL },
 347   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 348 };
 349
 350 static const struct gdb_xml_element target_children[] = {
 351   { "architecture", NULL, NULL, GDB_XML_EF_OPTIONAL,
 352     NULL, tdesc_end_arch },
 353   { "feature", feature_attributes, feature_children,
 354     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 355     tdesc_start_feature, NULL },
 356   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 357 };
 358
 359 static const struct gdb_xml_element tdesc_elements[] = {
 360   { "target", target_attributes, target_children, GDB_XML_EF_NONE,
 361     tdesc_start_target, NULL },
 362   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 363 };
 364
 365 /* Parse DOCUMENT into a target description and return it.  */
 366
 367 static struct target_desc *
 368 tdesc_parse_xml (const char *document, xml_fetch_another fetcher,
 369                  void *fetcher_baton)
 370 {
 371   struct cleanup *back_to, *result_cleanup;
 372   struct gdb_xml_parser *parser;
 373   struct tdesc_parsing_data data;
 374   struct tdesc_xml_cache *cache;
 375   char *expanded_text;
 376   int ix;
 377
 378   /* Expand all XInclude directives.  */
 379   expanded_text = xml_process_xincludes (_("target description"),
 380                                          document, fetcher, fetcher_baton, 0);
 381   if (expanded_text == NULL)
 382     {
 383       warning (_("Could not load XML target description; ignoring"));
 384       return NULL;
 385     }
 386
 387   /* Check for an exact match in the list of descriptions we have
 388      previously parsed.  strcmp is a slightly inefficient way to
 389      do this; an SHA-1 checksum would work as well.  */
 390   for (ix = 0; VEC_iterate (tdesc_xml_cache_s, xml_cache, ix, cache); ix++)
 391     if (strcmp (cache->xml_document, expanded_text) == 0)
 392       {
 393        xfree (expanded_text);
 394        return cache->tdesc;
 395       }
 396
 397   back_to = make_cleanup (null_cleanup, NULL);
 398   parser = gdb_xml_create_parser_and_cleanup (_("target description"),
 399                                               tdesc_elements, &data);
 400   gdb_xml_use_dtd (parser, "gdb-target.dtd");
 401
 402   memset (&data, 0, sizeof (struct tdesc_parsing_data));
 403   data.tdesc = allocate_target_description ();
 404   result_cleanup = make_cleanup_free_target_description (data.tdesc);
 405   make_cleanup (xfree, expanded_text);
 406
 407   if (gdb_xml_parse (parser, expanded_text) == 0)
 408     {
 409       /* Parsed successfully.  */
 410       struct tdesc_xml_cache new_cache;
 411
 412       new_cache.xml_document = expanded_text;
 413       new_cache.tdesc = data.tdesc;
 414       VEC_safe_push (tdesc_xml_cache_s, xml_cache, &new_cache);
 415       discard_cleanups (result_cleanup);
 416       do_cleanups (back_to);
 417       return data.tdesc;
 418     }
 419   else
 420     {
 421       warning (_("Could not load XML target description; ignoring"));
 422       do_cleanups (back_to);
 423       return NULL;
 424     }
 425 }
 426 #endif /* HAVE_LIBEXPAT */
 427 \f
 428
 429 /* Close FILE.  */
 430
 431 static void
 432 do_cleanup_fclose (void *file)
 433 {
 434   fclose (file);
 435 }
 436
 437 /* Open FILENAME, read all its text into memory, close it, and return
 438    the text.  If something goes wrong, return NULL and warn.  */
 439
 440 static char *
 441 fetch_xml_from_file (const char *filename, void *baton)
 442 {
 443   const char *dirname = baton;
 444   FILE *file;
 445   struct cleanup *back_to;
 446   char *text;
 447   size_t len, offset;
 448
 449   if (dirname && *dirname)
 450     {
 451       char *fullname = concat (dirname, "/", filename, NULL);
 452       if (fullname == NULL)
 453         nomem (0);
 454       file = fopen (fullname, FOPEN_RT);
 455       xfree (fullname);
 456     }
 457   else
 458     file = fopen (filename, FOPEN_RT);
 459
 460   if (file == NULL)
 461     return NULL;
 462
 463   back_to = make_cleanup (do_cleanup_fclose, file);
 464
 465   /* Read in the whole file, one chunk at a time.  */
 466   len = 4096;
 467   offset = 0;
 468   text = xmalloc (len);
 469   make_cleanup (free_current_contents, &text);
 470   while (1)
 471     {
 472       size_t bytes_read;
 473
 474       /* Continue reading where the last read left off.  Leave at least
 475          one byte so that we can NUL-terminate the result.  */
 476       bytes_read = fread (text + offset, 1, len - offset - 1, file);
 477       if (ferror (file))
 478         {
 479           warning (_("Read error from \"%s\""), filename);
 480           do_cleanups (back_to);
 481           return NULL;
 482         }
 483
 484       offset += bytes_read;
 485
 486       if (feof (file))
 487         break;
 488
 489       len = len * 2;
 490       text = xrealloc (text, len);
 491     }
 492
 493   fclose (file);
 494   discard_cleanups (back_to);
 495
 496   text[offset] = '\0';
 497   return text;
 498 }
 499
 500 /* Read an XML target description from FILENAME.  Parse it, and return
 501    the parsed description.  */
 502
 503 const struct target_desc *
 504 file_read_description_xml (const char *filename)
 505 {
 506   struct target_desc *tdesc;
 507   char *tdesc_str;
 508   struct cleanup *back_to;
 509   char *dirname;
 510
 511   tdesc_str = fetch_xml_from_file (filename, NULL);
 512   if (tdesc_str == NULL)
 513     {
 514       warning (_("Could not open \"%s\""), filename);
 515       return NULL;
 516     }
 517
 518   back_to = make_cleanup (xfree, tdesc_str);
 519
 520   dirname = ldirname (filename);
 521   if (dirname != NULL)
 522     make_cleanup (xfree, dirname);
 523
 524   tdesc = tdesc_parse_xml (tdesc_str, fetch_xml_from_file, dirname);
 525   do_cleanups (back_to);
 526
 527   return tdesc;
 528 }
 529
 530 /* Read a string representation of available features from the target,
 531    using TARGET_OBJECT_AVAILABLE_FEATURES.  The returned string is
 532    malloc allocated and NUL-terminated.  NAME should be a non-NULL
 533    string identifying the XML document we want; the top level document
 534    is "target.xml".  Other calls may be performed for the DTD or
 535    for <xi:include>.  */
 536
 537 static char *
 538 fetch_available_features_from_target (const char *name, void *baton_)
 539 {
 540   struct target_ops *ops = baton_;
 541
 542   /* Read this object as a string.  This ensures that a NUL
 543      terminator is added.  */
 544   return target_read_stralloc (ops,
 545                                TARGET_OBJECT_AVAILABLE_FEATURES,
 546                                name);
 547 }
 548 \f
 549
 550 /* Read an XML target description using OPS.  Parse it, and return the
 551    parsed description.  */
 552
 553 const struct target_desc *
 554 target_read_description_xml (struct target_ops *ops)
 555 {
 556   struct target_desc *tdesc;
 557   char *tdesc_str;
 558   struct cleanup *back_to;
 559
 560   tdesc_str = fetch_available_features_from_target ("target.xml", ops);
 561   if (tdesc_str == NULL)
 562     return NULL;
 563
 564   back_to = make_cleanup (xfree, tdesc_str);
 565   tdesc = tdesc_parse_xml (tdesc_str,
 566                            fetch_available_features_from_target,
 567                            ops);
 568   do_cleanups (back_to);
 569
 570   return tdesc;
 571 }