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 2 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, write to the Free Software
  22    Foundation, Inc., 51 Franklin Street, Fifth Floor,
  23    Boston, MA 02110-1301, USA.  */
  24
  25 #include "defs.h"
  26 #include "gdbtypes.h"
  27 #include "target.h"
  28 #include "target-descriptions.h"
  29 #include "xml-support.h"
  30 #include "xml-tdesc.h"
  31
  32 #include "filenames.h"
  33
  34 #include "gdb_assert.h"
  35
  36 #if !defined(HAVE_LIBEXPAT)
  37
  38 /* Parse DOCUMENT into a target description.  Or don't, since we don't have
  39    an XML parser.  */
  40
  41 static struct target_desc *
  42 tdesc_parse_xml (const char *document, xml_fetch_another fetcher,
  43                  void *fetcher_baton)
  44 {
  45   static int have_warned;
  46
  47   if (!have_warned)
  48     {
  49       have_warned = 1;
  50       warning (_("Can not parse XML target description; XML support was "
  51                  "disabled at compile time"));
  52     }
  53
  54   return NULL;
  55 }
  56
  57 #else /* HAVE_LIBEXPAT */
  58
  59 /* A record of every XML description we have parsed.  We never discard
  60    old descriptions, because we never discard gdbarches.  As long as we
  61    have a gdbarch referencing this description, we want to have a copy
  62    of it here, so that if we parse the same XML document again we can
  63    return the same "struct target_desc *"; if they are not singletons,
  64    then we will create unnecessary duplicate gdbarches.  See
  65    gdbarch_list_lookup_by_info.  */
  66
  67 struct tdesc_xml_cache
  68 {
  69   const char *xml_document;
  70   struct target_desc *tdesc;
  71 };
  72 typedef struct tdesc_xml_cache tdesc_xml_cache_s;
  73 DEF_VEC_O(tdesc_xml_cache_s);
  74
  75 static VEC(tdesc_xml_cache_s) *xml_cache;
  76
  77 /* Callback data for target description parsing.  */
  78
  79 struct tdesc_parsing_data
  80 {
  81   /* The target description we are building.  */
  82   struct target_desc *tdesc;
  83
  84   /* The target feature we are currently parsing, or last parsed.  */
  85   struct tdesc_feature *current_feature;
  86
  87   /* The register number to use for the next register we see, if
  88      it does not have its own.  This starts at zero.  */
  89   int next_regnum;
  90
  91   /* The union we are currently parsing, or last parsed.  */
  92   struct type *current_union;
  93 };
  94
  95 /* Handle the end of an <architecture> element and its value.  */
  96
  97 static void
  98 tdesc_end_arch (struct gdb_xml_parser *parser,
  99                 const struct gdb_xml_element *element,
 100                 void *user_data, const char *body_text)
 101 {
 102   struct tdesc_parsing_data *data = user_data;
 103   const struct bfd_arch_info *arch;
 104
 105   arch = bfd_scan_arch (body_text);
 106   if (arch == NULL)
 107     gdb_xml_error (parser, _("Target description specified unknown "
 108                              "architecture \"%s\""), body_text);
 109   set_tdesc_architecture (data->tdesc, arch);
 110 }
 111
 112 /* Handle the start of a <feature> element.  */
 113
 114 static void
 115 tdesc_start_feature (struct gdb_xml_parser *parser,
 116                      const struct gdb_xml_element *element,
 117                      void *user_data, VEC(gdb_xml_value_s) *attributes)
 118 {
 119   struct tdesc_parsing_data *data = user_data;
 120   char *name = VEC_index (gdb_xml_value_s, attributes, 0)->value;
 121
 122   data->current_feature = tdesc_create_feature (data->tdesc, name);
 123 }
 124
 125 /* Handle the start of a <reg> element.  Fill in the optional
 126    attributes and attach it to the containing feature.  */
 127
 128 static void
 129 tdesc_start_reg (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   struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
 135   int ix = 0, length;
 136   char *name, *group, *type;
 137   int bitsize, regnum, save_restore;
 138
 139   length = VEC_length (gdb_xml_value_s, attributes);
 140
 141   name = attrs[ix++].value;
 142   bitsize = * (ULONGEST *) attrs[ix++].value;
 143
 144   if (ix < length && strcmp (attrs[ix].name, "regnum") == 0)
 145     regnum = * (ULONGEST *) attrs[ix++].value;
 146   else
 147     regnum = data->next_regnum;
 148
 149   if (ix < length && strcmp (attrs[ix].name, "type") == 0)
 150     type = attrs[ix++].value;
 151   else
 152     type = "int";
 153
 154   if (ix < length && strcmp (attrs[ix].name, "group") == 0)
 155     group = attrs[ix++].value;
 156   else
 157     group = NULL;
 158
 159   if (ix < length && strcmp (attrs[ix].name, "save-restore") == 0)
 160     save_restore = * (ULONGEST *) attrs[ix++].value;
 161   else
 162     save_restore = 1;
 163
 164   if (strcmp (type, "int") != 0
 165       && strcmp (type, "float") != 0
 166       && tdesc_named_type (data->current_feature, type) == NULL)
 167     gdb_xml_error (parser, _("Register \"%s\" has unknown type \"%s\""),
 168                    name, type);
 169
 170   tdesc_create_reg (data->current_feature, name, regnum, save_restore, group,
 171                     bitsize, type);
 172
 173   data->next_regnum = regnum + 1;
 174 }
 175
 176 /* Handle the start of a <union> element.  Initialize the type and
 177    record it with the current feature.  */
 178
 179 static void
 180 tdesc_start_union (struct gdb_xml_parser *parser,
 181                    const struct gdb_xml_element *element,
 182                    void *user_data, VEC(gdb_xml_value_s) *attributes)
 183 {
 184   struct tdesc_parsing_data *data = user_data;
 185   char *id = VEC_index (gdb_xml_value_s, attributes, 0)->value;
 186   struct type *type;
 187
 188   type = init_composite_type (NULL, TYPE_CODE_UNION);
 189   TYPE_NAME (type) = xstrdup (id);
 190   tdesc_record_type (data->current_feature, type);
 191   data->current_union = type;
 192 }
 193
 194 /* Handle the end of a <union> element.  */
 195
 196 static void
 197 tdesc_end_union (struct gdb_xml_parser *parser,
 198                  const struct gdb_xml_element *element,
 199                  void *user_data, const char *body_text)
 200 {
 201   struct tdesc_parsing_data *data = user_data;
 202   int i;
 203
 204   /* If any of the children of this union are vectors, flag the union
 205      as a vector also.  This allows e.g. a union of two vector types
 206      to show up automatically in "info vector".  */
 207   for (i = 0; i < TYPE_NFIELDS (data->current_union); i++)
 208     if (TYPE_VECTOR (TYPE_FIELD_TYPE (data->current_union, i)))
 209       {
 210         TYPE_FLAGS (data->current_union) |= TYPE_FLAG_VECTOR;
 211         break;
 212       }
 213 }
 214
 215 /* Handle the start of a <field> element.  Attach the field to the
 216    current union.  */
 217
 218 static void
 219 tdesc_start_field (struct gdb_xml_parser *parser,
 220                    const struct gdb_xml_element *element,
 221                    void *user_data, VEC(gdb_xml_value_s) *attributes)
 222 {
 223   struct tdesc_parsing_data *data = user_data;
 224   struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
 225   struct type *type, *field_type;
 226   char *field_name, *field_type_id;
 227
 228   field_name = attrs[0].value;
 229   field_type_id = attrs[1].value;
 230
 231   field_type = tdesc_named_type (data->current_feature, field_type_id);
 232   if (field_type == NULL)
 233     gdb_xml_error (parser, _("Union field \"%s\" references undefined "
 234                              "type \"%s\""),
 235                    field_name, field_type_id);
 236
 237   append_composite_type_field (data->current_union, xstrdup (field_name),
 238                                field_type);
 239 }
 240
 241 /* Handle the start of a <vector> element.  Initialize the type and
 242    record it with the current feature.  */
 243
 244 static void
 245 tdesc_start_vector (struct gdb_xml_parser *parser,
 246                     const struct gdb_xml_element *element,
 247                     void *user_data, VEC(gdb_xml_value_s) *attributes)
 248 {
 249   struct tdesc_parsing_data *data = user_data;
 250   struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
 251   struct type *type, *field_type, *range_type;
 252   char *id, *field_type_id;
 253   int count;
 254
 255   id = attrs[0].value;
 256   field_type_id = attrs[1].value;
 257   count = * (ULONGEST *) attrs[2].value;
 258
 259   field_type = tdesc_named_type (data->current_feature, field_type_id);
 260   if (field_type == NULL)
 261     gdb_xml_error (parser, _("Vector \"%s\" references undefined type \"%s\""),
 262                    id, field_type_id);
 263
 264   /* A vector is just an array plus a special flag.  */
 265   range_type = create_range_type (NULL, builtin_type_int, 0, count - 1);
 266   type = create_array_type (NULL, field_type, range_type);
 267   TYPE_NAME (type) = xstrdup (id);
 268
 269   TYPE_FLAGS (type) |= TYPE_FLAG_VECTOR;
 270
 271   tdesc_record_type (data->current_feature, type);
 272 }
 273
 274 /* The elements and attributes of an XML target description.  */
 275
 276 static const struct gdb_xml_attribute field_attributes[] = {
 277   { "name", GDB_XML_AF_NONE, NULL, NULL },
 278   { "type", GDB_XML_AF_NONE, NULL, NULL },
 279   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 280 };
 281
 282 static const struct gdb_xml_element union_children[] = {
 283   { "field", field_attributes, NULL, GDB_XML_EF_REPEATABLE,
 284     tdesc_start_field, NULL },
 285   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 286 };
 287
 288 static const struct gdb_xml_attribute reg_attributes[] = {
 289   { "name", GDB_XML_AF_NONE, NULL, NULL },
 290   { "bitsize", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 291   { "regnum", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },
 292   { "type", GDB_XML_AF_OPTIONAL, NULL, NULL },
 293   { "group", GDB_XML_AF_OPTIONAL, NULL, NULL },
 294   { "save-restore", GDB_XML_AF_OPTIONAL,
 295     gdb_xml_parse_attr_enum, gdb_xml_enums_boolean },
 296   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 297 };
 298
 299 static const struct gdb_xml_attribute union_attributes[] = {
 300   { "id", GDB_XML_AF_NONE, NULL, NULL },
 301   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 302 };
 303
 304 static const struct gdb_xml_attribute vector_attributes[] = {
 305   { "id", GDB_XML_AF_NONE, NULL, NULL },
 306   { "type", GDB_XML_AF_NONE, NULL, NULL },
 307   { "count", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 308   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 309 };
 310
 311 static const struct gdb_xml_attribute feature_attributes[] = {
 312   { "name", GDB_XML_AF_NONE, NULL, NULL },
 313   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 314 };
 315
 316 static const struct gdb_xml_element feature_children[] = {
 317   { "reg", reg_attributes, NULL,
 318     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 319     tdesc_start_reg, NULL },
 320   { "union", union_attributes, union_children,
 321     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 322     tdesc_start_union, tdesc_end_union },
 323   { "vector", vector_attributes, NULL,
 324     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 325     tdesc_start_vector, NULL },
 326   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 327 };
 328
 329 static const struct gdb_xml_element target_children[] = {
 330   { "architecture", NULL, NULL, GDB_XML_EF_OPTIONAL,
 331     NULL, tdesc_end_arch },
 332   { "feature", feature_attributes, feature_children,
 333     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 334     tdesc_start_feature, NULL },
 335   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 336 };
 337
 338 static const struct gdb_xml_element tdesc_elements[] = {
 339   { "target", NULL, target_children, GDB_XML_EF_NONE,
 340     NULL, NULL },
 341   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 342 };
 343
 344 /* Parse DOCUMENT into a target description and return it.  */
 345
 346 static struct target_desc *
 347 tdesc_parse_xml (const char *document, xml_fetch_another fetcher,
 348                  void *fetcher_baton)
 349 {
 350   struct cleanup *back_to, *result_cleanup;
 351   struct gdb_xml_parser *parser;
 352   struct tdesc_parsing_data data;
 353   struct tdesc_xml_cache *cache;
 354   char *expanded_text;
 355   int ix;
 356
 357   /* Expand all XInclude directives.  */
 358   expanded_text = xml_process_xincludes (_("target description"),
 359                                          document, fetcher, fetcher_baton, 0);
 360   if (expanded_text == NULL)
 361     {
 362       warning (_("Could not load XML target description; ignoring"));
 363       return NULL;
 364     }
 365
 366   /* Check for an exact match in the list of descriptions we have
 367      previously parsed.  strcmp is a slightly inefficient way to
 368      do this; an SHA-1 checksum would work as well.  */
 369   for (ix = 0; VEC_iterate (tdesc_xml_cache_s, xml_cache, ix, cache); ix++)
 370     if (strcmp (cache->xml_document, expanded_text) == 0)
 371       {
 372        xfree (expanded_text);
 373        return cache->tdesc;
 374       }
 375
 376   back_to = make_cleanup (null_cleanup, NULL);
 377   parser = gdb_xml_create_parser_and_cleanup (_("target description"),
 378                                               tdesc_elements, &data);
 379   gdb_xml_use_dtd (parser, "gdb-target.dtd");
 380
 381   memset (&data, 0, sizeof (struct tdesc_parsing_data));
 382   data.tdesc = allocate_target_description ();
 383   result_cleanup = make_cleanup_free_target_description (data.tdesc);
 384   make_cleanup (xfree, expanded_text);
 385
 386   if (gdb_xml_parse (parser, expanded_text) == 0)
 387     {
 388       /* Parsed successfully.  */
 389       struct tdesc_xml_cache new_cache;
 390
 391       new_cache.xml_document = expanded_text;
 392       new_cache.tdesc = data.tdesc;
 393       VEC_safe_push (tdesc_xml_cache_s, xml_cache, &new_cache);
 394       discard_cleanups (result_cleanup);
 395       do_cleanups (back_to);
 396       return data.tdesc;
 397     }
 398   else
 399     {
 400       warning (_("Could not load XML target description; ignoring"));
 401       do_cleanups (back_to);
 402       return NULL;
 403     }
 404 }
 405 #endif /* HAVE_LIBEXPAT */
 406 \f
 407
 408 /* Close FILE.  */
 409
 410 static void
 411 do_cleanup_fclose (void *file)
 412 {
 413   fclose (file);
 414 }
 415
 416 /* Open FILENAME, read all its text into memory, close it, and return
 417    the text.  If something goes wrong, return NULL and warn.  */
 418
 419 static char *
 420 fetch_xml_from_file (const char *filename, void *baton)
 421 {
 422   const char *dirname = baton;
 423   FILE *file;
 424   struct cleanup *back_to;
 425   char *text;
 426   size_t len, offset;
 427
 428   if (dirname && *dirname)
 429     {
 430       char *fullname = concat (dirname, "/", filename, NULL);
 431       if (fullname == NULL)
 432         nomem (0);
 433       file = fopen (fullname, FOPEN_RT);
 434       xfree (fullname);
 435     }
 436   else
 437     file = fopen (filename, FOPEN_RT);
 438
 439   if (file == NULL)
 440     return NULL;
 441
 442   back_to = make_cleanup (do_cleanup_fclose, file);
 443
 444   /* Read in the whole file, one chunk at a time.  */
 445   len = 4096;
 446   offset = 0;
 447   text = xmalloc (len);
 448   make_cleanup (free_current_contents, &text);
 449   while (1)
 450     {
 451       size_t bytes_read;
 452
 453       /* Continue reading where the last read left off.  Leave at least
 454          one byte so that we can NUL-terminate the result.  */
 455       bytes_read = fread (text + offset, 1, len - offset - 1, file);
 456       if (ferror (file))
 457         {
 458           warning (_("Read error from \"%s\""), filename);
 459           do_cleanups (back_to);
 460           return NULL;
 461         }
 462
 463       offset += bytes_read;
 464
 465       if (feof (file))
 466         break;
 467
 468       len = len * 2;
 469       text = xrealloc (text, len);
 470     }
 471
 472   fclose (file);
 473   discard_cleanups (back_to);
 474
 475   text[offset] = '\0';
 476   return text;
 477 }
 478
 479 /* Read an XML target description from FILENAME.  Parse it, and return
 480    the parsed description.  */
 481
 482 const struct target_desc *
 483 file_read_description_xml (const char *filename)
 484 {
 485   struct target_desc *tdesc;
 486   char *tdesc_str;
 487   struct cleanup *back_to;
 488   const char *base;
 489   char *dirname;
 490
 491   tdesc_str = fetch_xml_from_file (filename, NULL);
 492   if (tdesc_str == NULL)
 493     {
 494       warning (_("Could not open \"%s\""), filename);
 495       return NULL;
 496     }
 497
 498   back_to = make_cleanup (xfree, tdesc_str);
 499
 500   /* Simple, portable version of dirname that does not modify its
 501      argument.  */
 502   base = lbasename (filename);
 503   while (base > filename && IS_DIR_SEPARATOR (base[-1]))
 504     --base;
 505   if (base > filename)
 506     {
 507       dirname = xmalloc (base - filename + 2);
 508       memcpy (dirname, filename, base - filename);
 509
 510       /* On DOS based file systems, convert "d:foo" to "d:.", so that
 511          we create "d:./bar" later instead of the (different)
 512          "d:/bar".  */
 513       if (base - filename == 2 && IS_ABSOLUTE_PATH (base)
 514           && !IS_DIR_SEPARATOR (filename[0]))
 515         dirname[base++ - filename] = '.';
 516
 517       dirname[base - filename] = '\0';
 518       make_cleanup (xfree, dirname);
 519     }
 520   else
 521     dirname = NULL;
 522
 523   tdesc = tdesc_parse_xml (tdesc_str, fetch_xml_from_file, dirname);
 524   do_cleanups (back_to);
 525
 526   return tdesc;
 527 }
 528
 529 /* Read a string representation of available features from the target,
 530    using TARGET_OBJECT_AVAILABLE_FEATURES.  The returned string is
 531    malloc allocated and NUL-terminated.  NAME should be a non-NULL
 532    string identifying the XML document we want; the top level document
 533    is "target.xml".  Other calls may be performed for the DTD or
 534    for <xi:include>.  */
 535
 536 static char *
 537 fetch_available_features_from_target (const char *name, void *baton_)
 538 {
 539   struct target_ops *ops = baton_;
 540
 541   /* Read this object as a string.  This ensures that a NUL
 542      terminator is added.  */
 543   return target_read_stralloc (ops,
 544                                TARGET_OBJECT_AVAILABLE_FEATURES,
 545                                name);
 546 }
 547 \f
 548
 549 /* Read an XML target description using OPS.  Parse it, and return the
 550    parsed description.  */
 551
 552 const struct target_desc *
 553 target_read_description_xml (struct target_ops *ops)
 554 {
 555   struct target_desc *tdesc;
 556   char *tdesc_str;
 557   struct cleanup *back_to;
 558
 559   tdesc_str = fetch_available_features_from_target ("target.xml", ops);
 560   if (tdesc_str == NULL)
 561     return NULL;
 562
 563   back_to = make_cleanup (xfree, tdesc_str);
 564   tdesc = tdesc_parse_xml (tdesc_str,
 565                            fetch_available_features_from_target,
 566                            ops);
 567   do_cleanups (back_to);
 568
 569   return tdesc;
 570 }