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   type = init_vector_type (field_type, count);
 281   TYPE_NAME (type) = xstrdup (id);
 282
 283   tdesc_record_type (data->current_feature, type);
 284 }
 285
 286 /* The elements and attributes of an XML target description.  */
 287
 288 static const struct gdb_xml_attribute field_attributes[] = {
 289   { "name", GDB_XML_AF_NONE, NULL, NULL },
 290   { "type", GDB_XML_AF_NONE, NULL, NULL },
 291   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 292 };
 293
 294 static const struct gdb_xml_element union_children[] = {
 295   { "field", field_attributes, NULL, GDB_XML_EF_REPEATABLE,
 296     tdesc_start_field, NULL },
 297   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 298 };
 299
 300 static const struct gdb_xml_attribute reg_attributes[] = {
 301   { "name", GDB_XML_AF_NONE, NULL, NULL },
 302   { "bitsize", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 303   { "regnum", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },
 304   { "type", GDB_XML_AF_OPTIONAL, NULL, NULL },
 305   { "group", GDB_XML_AF_OPTIONAL, NULL, NULL },
 306   { "save-restore", GDB_XML_AF_OPTIONAL,
 307     gdb_xml_parse_attr_enum, gdb_xml_enums_boolean },
 308   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 309 };
 310
 311 static const struct gdb_xml_attribute union_attributes[] = {
 312   { "id", GDB_XML_AF_NONE, NULL, NULL },
 313   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 314 };
 315
 316 static const struct gdb_xml_attribute vector_attributes[] = {
 317   { "id", GDB_XML_AF_NONE, NULL, NULL },
 318   { "type", GDB_XML_AF_NONE, NULL, NULL },
 319   { "count", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 320   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 321 };
 322
 323 static const struct gdb_xml_attribute feature_attributes[] = {
 324   { "name", GDB_XML_AF_NONE, NULL, NULL },
 325   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 326 };
 327
 328 static const struct gdb_xml_element feature_children[] = {
 329   { "reg", reg_attributes, NULL,
 330     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 331     tdesc_start_reg, NULL },
 332   { "union", union_attributes, union_children,
 333     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 334     tdesc_start_union, tdesc_end_union },
 335   { "vector", vector_attributes, NULL,
 336     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 337     tdesc_start_vector, NULL },
 338   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 339 };
 340
 341 static const struct gdb_xml_attribute target_attributes[] = {
 342   { "version", GDB_XML_AF_NONE, NULL, NULL },
 343   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 344 };
 345
 346 static const struct gdb_xml_element target_children[] = {
 347   { "architecture", NULL, NULL, GDB_XML_EF_OPTIONAL,
 348     NULL, tdesc_end_arch },
 349   { "feature", feature_attributes, feature_children,
 350     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 351     tdesc_start_feature, NULL },
 352   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 353 };
 354
 355 static const struct gdb_xml_element tdesc_elements[] = {
 356   { "target", target_attributes, target_children, GDB_XML_EF_NONE,
 357     tdesc_start_target, NULL },
 358   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 359 };
 360
 361 /* Parse DOCUMENT into a target description and return it.  */
 362
 363 static struct target_desc *
 364 tdesc_parse_xml (const char *document, xml_fetch_another fetcher,
 365                  void *fetcher_baton)
 366 {
 367   struct cleanup *back_to, *result_cleanup;
 368   struct gdb_xml_parser *parser;
 369   struct tdesc_parsing_data data;
 370   struct tdesc_xml_cache *cache;
 371   char *expanded_text;
 372   int ix;
 373
 374   /* Expand all XInclude directives.  */
 375   expanded_text = xml_process_xincludes (_("target description"),
 376                                          document, fetcher, fetcher_baton, 0);
 377   if (expanded_text == NULL)
 378     {
 379       warning (_("Could not load XML target description; ignoring"));
 380       return NULL;
 381     }
 382
 383   /* Check for an exact match in the list of descriptions we have
 384      previously parsed.  strcmp is a slightly inefficient way to
 385      do this; an SHA-1 checksum would work as well.  */
 386   for (ix = 0; VEC_iterate (tdesc_xml_cache_s, xml_cache, ix, cache); ix++)
 387     if (strcmp (cache->xml_document, expanded_text) == 0)
 388       {
 389        xfree (expanded_text);
 390        return cache->tdesc;
 391       }
 392
 393   back_to = make_cleanup (null_cleanup, NULL);
 394   parser = gdb_xml_create_parser_and_cleanup (_("target description"),
 395                                               tdesc_elements, &data);
 396   gdb_xml_use_dtd (parser, "gdb-target.dtd");
 397
 398   memset (&data, 0, sizeof (struct tdesc_parsing_data));
 399   data.tdesc = allocate_target_description ();
 400   result_cleanup = make_cleanup_free_target_description (data.tdesc);
 401   make_cleanup (xfree, expanded_text);
 402
 403   if (gdb_xml_parse (parser, expanded_text) == 0)
 404     {
 405       /* Parsed successfully.  */
 406       struct tdesc_xml_cache new_cache;
 407
 408       new_cache.xml_document = expanded_text;
 409       new_cache.tdesc = data.tdesc;
 410       VEC_safe_push (tdesc_xml_cache_s, xml_cache, &new_cache);
 411       discard_cleanups (result_cleanup);
 412       do_cleanups (back_to);
 413       return data.tdesc;
 414     }
 415   else
 416     {
 417       warning (_("Could not load XML target description; ignoring"));
 418       do_cleanups (back_to);
 419       return NULL;
 420     }
 421 }
 422 #endif /* HAVE_LIBEXPAT */
 423 \f
 424
 425 /* Close FILE.  */
 426
 427 static void
 428 do_cleanup_fclose (void *file)
 429 {
 430   fclose (file);
 431 }
 432
 433 /* Open FILENAME, read all its text into memory, close it, and return
 434    the text.  If something goes wrong, return NULL and warn.  */
 435
 436 static char *
 437 fetch_xml_from_file (const char *filename, void *baton)
 438 {
 439   const char *dirname = baton;
 440   FILE *file;
 441   struct cleanup *back_to;
 442   char *text;
 443   size_t len, offset;
 444
 445   if (dirname && *dirname)
 446     {
 447       char *fullname = concat (dirname, "/", filename, NULL);
 448       if (fullname == NULL)
 449         nomem (0);
 450       file = fopen (fullname, FOPEN_RT);
 451       xfree (fullname);
 452     }
 453   else
 454     file = fopen (filename, FOPEN_RT);
 455
 456   if (file == NULL)
 457     return NULL;
 458
 459   back_to = make_cleanup (do_cleanup_fclose, file);
 460
 461   /* Read in the whole file, one chunk at a time.  */
 462   len = 4096;
 463   offset = 0;
 464   text = xmalloc (len);
 465   make_cleanup (free_current_contents, &text);
 466   while (1)
 467     {
 468       size_t bytes_read;
 469
 470       /* Continue reading where the last read left off.  Leave at least
 471          one byte so that we can NUL-terminate the result.  */
 472       bytes_read = fread (text + offset, 1, len - offset - 1, file);
 473       if (ferror (file))
 474         {
 475           warning (_("Read error from \"%s\""), filename);
 476           do_cleanups (back_to);
 477           return NULL;
 478         }
 479
 480       offset += bytes_read;
 481
 482       if (feof (file))
 483         break;
 484
 485       len = len * 2;
 486       text = xrealloc (text, len);
 487     }
 488
 489   fclose (file);
 490   discard_cleanups (back_to);
 491
 492   text[offset] = '\0';
 493   return text;
 494 }
 495
 496 /* Read an XML target description from FILENAME.  Parse it, and return
 497    the parsed description.  */
 498
 499 const struct target_desc *
 500 file_read_description_xml (const char *filename)
 501 {
 502   struct target_desc *tdesc;
 503   char *tdesc_str;
 504   struct cleanup *back_to;
 505   char *dirname;
 506
 507   tdesc_str = fetch_xml_from_file (filename, NULL);
 508   if (tdesc_str == NULL)
 509     {
 510       warning (_("Could not open \"%s\""), filename);
 511       return NULL;
 512     }
 513
 514   back_to = make_cleanup (xfree, tdesc_str);
 515
 516   dirname = ldirname (filename);
 517   if (dirname != NULL)
 518     make_cleanup (xfree, dirname);
 519
 520   tdesc = tdesc_parse_xml (tdesc_str, fetch_xml_from_file, dirname);
 521   do_cleanups (back_to);
 522
 523   return tdesc;
 524 }
 525
 526 /* Read a string representation of available features from the target,
 527    using TARGET_OBJECT_AVAILABLE_FEATURES.  The returned string is
 528    malloc allocated and NUL-terminated.  NAME should be a non-NULL
 529    string identifying the XML document we want; the top level document
 530    is "target.xml".  Other calls may be performed for the DTD or
 531    for <xi:include>.  */
 532
 533 static char *
 534 fetch_available_features_from_target (const char *name, void *baton_)
 535 {
 536   struct target_ops *ops = baton_;
 537
 538   /* Read this object as a string.  This ensures that a NUL
 539      terminator is added.  */
 540   return target_read_stralloc (ops,
 541                                TARGET_OBJECT_AVAILABLE_FEATURES,
 542                                name);
 543 }
 544 \f
 545
 546 /* Read an XML target description using OPS.  Parse it, and return the
 547    parsed description.  */
 548
 549 const struct target_desc *
 550 target_read_description_xml (struct target_ops *ops)
 551 {
 552   struct target_desc *tdesc;
 553   char *tdesc_str;
 554   struct cleanup *back_to;
 555
 556   tdesc_str = fetch_available_features_from_target ("target.xml", ops);
 557   if (tdesc_str == NULL)
 558     return NULL;
 559
 560   back_to = make_cleanup (xfree, tdesc_str);
 561   tdesc = tdesc_parse_xml (tdesc_str,
 562                            fetch_available_features_from_target,
 563                            ops);
 564   do_cleanups (back_to);
 565
 566   return tdesc;
 567 }