gdb/xml-tdesc.c

   1 /* XML target description support for GDB.
   2
   3    Copyright (C) 2006, 2008, 2009 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 "target.h"
  24 #include "target-descriptions.h"
  25 #include "xml-support.h"
  26 #include "xml-tdesc.h"
  27 #include "osabi.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 tdesc_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 end of an <osabi> element and its value.  */
 110
 111 static void
 112 tdesc_end_osabi (struct gdb_xml_parser *parser,
 113                  const struct gdb_xml_element *element,
 114                  void *user_data, const char *body_text)
 115 {
 116   struct tdesc_parsing_data *data = user_data;
 117   enum gdb_osabi osabi;
 118
 119   osabi = osabi_from_tdesc_string (body_text);
 120   if (osabi == GDB_OSABI_UNKNOWN)
 121     warning (_("Target description specified unknown osabi \"%s\""),
 122              body_text);
 123   else
 124     set_tdesc_osabi (data->tdesc, osabi);
 125 }
 126
 127 /* Handle the start of a <target> element.  */
 128
 129 static void
 130 tdesc_start_target (struct gdb_xml_parser *parser,
 131                     const struct gdb_xml_element *element,
 132                     void *user_data, VEC(gdb_xml_value_s) *attributes)
 133 {
 134   struct tdesc_parsing_data *data = user_data;
 135   char *version = VEC_index (gdb_xml_value_s, attributes, 0)->value;
 136
 137   if (strcmp (version, "1.0") != 0)
 138     gdb_xml_error (parser,
 139                    _("Target description has unsupported version \"%s\""),
 140                    version);
 141 }
 142
 143 /* Handle the start of a <feature> element.  */
 144
 145 static void
 146 tdesc_start_feature (struct gdb_xml_parser *parser,
 147                      const struct gdb_xml_element *element,
 148                      void *user_data, VEC(gdb_xml_value_s) *attributes)
 149 {
 150   struct tdesc_parsing_data *data = user_data;
 151   char *name = VEC_index (gdb_xml_value_s, attributes, 0)->value;
 152
 153   data->current_feature = tdesc_create_feature (data->tdesc, name);
 154 }
 155
 156 /* Handle the start of a <reg> element.  Fill in the optional
 157    attributes and attach it to the containing feature.  */
 158
 159 static void
 160 tdesc_start_reg (struct gdb_xml_parser *parser,
 161                  const struct gdb_xml_element *element,
 162                  void *user_data, VEC(gdb_xml_value_s) *attributes)
 163 {
 164   struct tdesc_parsing_data *data = user_data;
 165   struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
 166   int ix = 0, length;
 167   char *name, *group, *type;
 168   int bitsize, regnum, save_restore;
 169
 170   length = VEC_length (gdb_xml_value_s, attributes);
 171
 172   name = attrs[ix++].value;
 173   bitsize = * (ULONGEST *) attrs[ix++].value;
 174
 175   if (ix < length && strcmp (attrs[ix].name, "regnum") == 0)
 176     regnum = * (ULONGEST *) attrs[ix++].value;
 177   else
 178     regnum = data->next_regnum;
 179
 180   if (ix < length && strcmp (attrs[ix].name, "type") == 0)
 181     type = attrs[ix++].value;
 182   else
 183     type = "int";
 184
 185   if (ix < length && strcmp (attrs[ix].name, "group") == 0)
 186     group = attrs[ix++].value;
 187   else
 188     group = NULL;
 189
 190   if (ix < length && strcmp (attrs[ix].name, "save-restore") == 0)
 191     save_restore = * (ULONGEST *) attrs[ix++].value;
 192   else
 193     save_restore = 1;
 194
 195   if (strcmp (type, "int") != 0
 196       && strcmp (type, "float") != 0
 197       && tdesc_named_type (data->current_feature, type) == NULL)
 198     gdb_xml_error (parser, _("Register \"%s\" has unknown type \"%s\""),
 199                    name, type);
 200
 201   tdesc_create_reg (data->current_feature, name, regnum, save_restore, group,
 202                     bitsize, type);
 203
 204   data->next_regnum = regnum + 1;
 205 }
 206
 207 /* Handle the start of a <union> element.  Initialize the type and
 208    record it with the current feature.  */
 209
 210 static void
 211 tdesc_start_union (struct gdb_xml_parser *parser,
 212                    const struct gdb_xml_element *element,
 213                    void *user_data, VEC(gdb_xml_value_s) *attributes)
 214 {
 215   struct tdesc_parsing_data *data = user_data;
 216   char *id = VEC_index (gdb_xml_value_s, attributes, 0)->value;
 217
 218   data->current_union = tdesc_create_union (data->current_feature, id);
 219 }
 220
 221 /* Handle the start of a <field> element.  Attach the field to the
 222    current union.  */
 223
 224 static void
 225 tdesc_start_field (struct gdb_xml_parser *parser,
 226                    const struct gdb_xml_element *element,
 227                    void *user_data, VEC(gdb_xml_value_s) *attributes)
 228 {
 229   struct tdesc_parsing_data *data = user_data;
 230   struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
 231   struct tdesc_type *field_type;
 232   char *field_name, *field_type_id;
 233
 234   field_name = attrs[0].value;
 235   field_type_id = attrs[1].value;
 236
 237   field_type = tdesc_named_type (data->current_feature, field_type_id);
 238   if (field_type == NULL)
 239     gdb_xml_error (parser, _("Union field \"%s\" references undefined "
 240                              "type \"%s\""),
 241                    field_name, field_type_id);
 242
 243   tdesc_add_field (data->current_union, field_name, field_type);
 244 }
 245
 246 /* Handle the start of a <vector> element.  Initialize the type and
 247    record it with the current feature.  */
 248
 249 static void
 250 tdesc_start_vector (struct gdb_xml_parser *parser,
 251                     const struct gdb_xml_element *element,
 252                     void *user_data, VEC(gdb_xml_value_s) *attributes)
 253 {
 254   struct tdesc_parsing_data *data = user_data;
 255   struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
 256   struct tdesc_type *field_type;
 257   char *id, *field_type_id;
 258   int count;
 259
 260   id = attrs[0].value;
 261   field_type_id = attrs[1].value;
 262   count = * (ULONGEST *) attrs[2].value;
 263
 264   field_type = tdesc_named_type (data->current_feature, field_type_id);
 265   if (field_type == NULL)
 266     gdb_xml_error (parser, _("Vector \"%s\" references undefined type \"%s\""),
 267                    id, field_type_id);
 268
 269   tdesc_create_vector (data->current_feature, id, field_type, count);
 270 }
 271
 272 /* The elements and attributes of an XML target description.  */
 273
 274 static const struct gdb_xml_attribute field_attributes[] = {
 275   { "name", GDB_XML_AF_NONE, NULL, NULL },
 276   { "type", GDB_XML_AF_NONE, NULL, NULL },
 277   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 278 };
 279
 280 static const struct gdb_xml_element union_children[] = {
 281   { "field", field_attributes, NULL, GDB_XML_EF_REPEATABLE,
 282     tdesc_start_field, NULL },
 283   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 284 };
 285
 286 static const struct gdb_xml_attribute reg_attributes[] = {
 287   { "name", GDB_XML_AF_NONE, NULL, NULL },
 288   { "bitsize", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 289   { "regnum", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },
 290   { "type", GDB_XML_AF_OPTIONAL, NULL, NULL },
 291   { "group", GDB_XML_AF_OPTIONAL, NULL, NULL },
 292   { "save-restore", GDB_XML_AF_OPTIONAL,
 293     gdb_xml_parse_attr_enum, gdb_xml_enums_boolean },
 294   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 295 };
 296
 297 static const struct gdb_xml_attribute union_attributes[] = {
 298   { "id", GDB_XML_AF_NONE, NULL, NULL },
 299   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 300 };
 301
 302 static const struct gdb_xml_attribute vector_attributes[] = {
 303   { "id", GDB_XML_AF_NONE, NULL, NULL },
 304   { "type", GDB_XML_AF_NONE, NULL, NULL },
 305   { "count", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 306   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 307 };
 308
 309 static const struct gdb_xml_attribute feature_attributes[] = {
 310   { "name", GDB_XML_AF_NONE, NULL, NULL },
 311   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 312 };
 313
 314 static const struct gdb_xml_element feature_children[] = {
 315   { "reg", reg_attributes, NULL,
 316     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 317     tdesc_start_reg, NULL },
 318   { "union", union_attributes, union_children,
 319     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 320     tdesc_start_union, NULL },
 321   { "vector", vector_attributes, NULL,
 322     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 323     tdesc_start_vector, NULL },
 324   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 325 };
 326
 327 static const struct gdb_xml_attribute target_attributes[] = {
 328   { "version", GDB_XML_AF_NONE, NULL, NULL },
 329   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 330 };
 331
 332 static const struct gdb_xml_element target_children[] = {
 333   { "architecture", NULL, NULL, GDB_XML_EF_OPTIONAL,
 334     NULL, tdesc_end_arch },
 335   { "osabi", NULL, NULL, GDB_XML_EF_OPTIONAL,
 336     NULL, tdesc_end_osabi },
 337   { "feature", feature_attributes, feature_children,
 338     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 339     tdesc_start_feature, NULL },
 340   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 341 };
 342
 343 static const struct gdb_xml_element tdesc_elements[] = {
 344   { "target", target_attributes, target_children, GDB_XML_EF_NONE,
 345     tdesc_start_target, NULL },
 346   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 347 };
 348
 349 /* Parse DOCUMENT into a target description and return it.  */
 350
 351 static struct target_desc *
 352 tdesc_parse_xml (const char *document, xml_fetch_another fetcher,
 353                  void *fetcher_baton)
 354 {
 355   struct cleanup *back_to, *result_cleanup;
 356   struct gdb_xml_parser *parser;
 357   struct tdesc_parsing_data data;
 358   struct tdesc_xml_cache *cache;
 359   char *expanded_text;
 360   int ix;
 361
 362   /* Expand all XInclude directives.  */
 363   expanded_text = xml_process_xincludes (_("target description"),
 364                                          document, fetcher, fetcher_baton, 0);
 365   if (expanded_text == NULL)
 366     {
 367       warning (_("Could not load XML target description; ignoring"));
 368       return NULL;
 369     }
 370
 371   /* Check for an exact match in the list of descriptions we have
 372      previously parsed.  strcmp is a slightly inefficient way to
 373      do this; an SHA-1 checksum would work as well.  */
 374   for (ix = 0; VEC_iterate (tdesc_xml_cache_s, xml_cache, ix, cache); ix++)
 375     if (strcmp (cache->xml_document, expanded_text) == 0)
 376       {
 377        xfree (expanded_text);
 378        return cache->tdesc;
 379       }
 380
 381   back_to = make_cleanup (null_cleanup, NULL);
 382   parser = gdb_xml_create_parser_and_cleanup (_("target description"),
 383                                               tdesc_elements, &data);
 384   gdb_xml_use_dtd (parser, "gdb-target.dtd");
 385
 386   memset (&data, 0, sizeof (struct tdesc_parsing_data));
 387   data.tdesc = allocate_target_description ();
 388   result_cleanup = make_cleanup_free_target_description (data.tdesc);
 389   make_cleanup (xfree, expanded_text);
 390
 391   if (gdb_xml_parse (parser, expanded_text) == 0)
 392     {
 393       /* Parsed successfully.  */
 394       struct tdesc_xml_cache new_cache;
 395
 396       new_cache.xml_document = expanded_text;
 397       new_cache.tdesc = data.tdesc;
 398       VEC_safe_push (tdesc_xml_cache_s, xml_cache, &new_cache);
 399       discard_cleanups (result_cleanup);
 400       do_cleanups (back_to);
 401       return data.tdesc;
 402     }
 403   else
 404     {
 405       warning (_("Could not load XML target description; ignoring"));
 406       do_cleanups (back_to);
 407       return NULL;
 408     }
 409 }
 410 #endif /* HAVE_LIBEXPAT */
 411 \f
 412
 413 /* Open FILENAME, read all its text into memory, close it, and return
 414    the text.  If something goes wrong, return NULL and warn.  */
 415
 416 static char *
 417 fetch_xml_from_file (const char *filename, void *baton)
 418 {
 419   const char *dirname = baton;
 420   FILE *file;
 421   struct cleanup *back_to;
 422   char *text;
 423   size_t len, offset;
 424
 425   if (dirname && *dirname)
 426     {
 427       char *fullname = concat (dirname, "/", filename, (char *) NULL);
 428       if (fullname == NULL)
 429         nomem (0);
 430       file = fopen (fullname, FOPEN_RT);
 431       xfree (fullname);
 432     }
 433   else
 434     file = fopen (filename, FOPEN_RT);
 435
 436   if (file == NULL)
 437     return NULL;
 438
 439   back_to = make_cleanup_fclose (file);
 440
 441   /* Read in the whole file, one chunk at a time.  */
 442   len = 4096;
 443   offset = 0;
 444   text = xmalloc (len);
 445   make_cleanup (free_current_contents, &text);
 446   while (1)
 447     {
 448       size_t bytes_read;
 449
 450       /* Continue reading where the last read left off.  Leave at least
 451          one byte so that we can NUL-terminate the result.  */
 452       bytes_read = fread (text + offset, 1, len - offset - 1, file);
 453       if (ferror (file))
 454         {
 455           warning (_("Read error from \"%s\""), filename);
 456           do_cleanups (back_to);
 457           return NULL;
 458         }
 459
 460       offset += bytes_read;
 461
 462       if (feof (file))
 463         break;
 464
 465       len = len * 2;
 466       text = xrealloc (text, len);
 467     }
 468
 469   fclose (file);
 470   discard_cleanups (back_to);
 471
 472   text[offset] = '\0';
 473   return text;
 474 }
 475
 476 /* Read an XML target description from FILENAME.  Parse it, and return
 477    the parsed description.  */
 478
 479 const struct target_desc *
 480 file_read_description_xml (const char *filename)
 481 {
 482   struct target_desc *tdesc;
 483   char *tdesc_str;
 484   struct cleanup *back_to;
 485   char *dirname;
 486
 487   tdesc_str = fetch_xml_from_file (filename, NULL);
 488   if (tdesc_str == NULL)
 489     {
 490       warning (_("Could not open \"%s\""), filename);
 491       return NULL;
 492     }
 493
 494   back_to = make_cleanup (xfree, tdesc_str);
 495
 496   dirname = ldirname (filename);
 497   if (dirname != NULL)
 498     make_cleanup (xfree, dirname);
 499
 500   tdesc = tdesc_parse_xml (tdesc_str, fetch_xml_from_file, dirname);
 501   do_cleanups (back_to);
 502
 503   return tdesc;
 504 }
 505
 506 /* Read a string representation of available features from the target,
 507    using TARGET_OBJECT_AVAILABLE_FEATURES.  The returned string is
 508    malloc allocated and NUL-terminated.  NAME should be a non-NULL
 509    string identifying the XML document we want; the top level document
 510    is "target.xml".  Other calls may be performed for the DTD or
 511    for <xi:include>.  */
 512
 513 static char *
 514 fetch_available_features_from_target (const char *name, void *baton_)
 515 {
 516   struct target_ops *ops = baton_;
 517
 518   /* Read this object as a string.  This ensures that a NUL
 519      terminator is added.  */
 520   return target_read_stralloc (ops,
 521                                TARGET_OBJECT_AVAILABLE_FEATURES,
 522                                name);
 523 }
 524 \f
 525
 526 /* Read an XML target description using OPS.  Parse it, and return the
 527    parsed description.  */
 528
 529 const struct target_desc *
 530 target_read_description_xml (struct target_ops *ops)
 531 {
 532   struct target_desc *tdesc;
 533   char *tdesc_str;
 534   struct cleanup *back_to;
 535
 536   tdesc_str = fetch_available_features_from_target ("target.xml", ops);
 537   if (tdesc_str == NULL)
 538     return NULL;
 539
 540   back_to = make_cleanup (xfree, tdesc_str);
 541   tdesc = tdesc_parse_xml (tdesc_str,
 542                            fetch_available_features_from_target,
 543                            ops);
 544   do_cleanups (back_to);
 545
 546   return tdesc;
 547 }