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