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 <target> element.  */
 113
 114 static void
 115 tdesc_start_target (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 *version = VEC_index (gdb_xml_value_s, attributes, 0)->value;
 121
 122   if (strcmp (version, "1.0") != 0)
 123     gdb_xml_error (parser,
 124                    _("Target description has unsupported version \"%s\""),
 125                    version);
 126 }
 127
 128 /* Handle the start of a <feature> element.  */
 129
 130 static void
 131 tdesc_start_feature (struct gdb_xml_parser *parser,
 132                      const struct gdb_xml_element *element,
 133                      void *user_data, VEC(gdb_xml_value_s) *attributes)
 134 {
 135   struct tdesc_parsing_data *data = user_data;
 136   char *name = VEC_index (gdb_xml_value_s, attributes, 0)->value;
 137
 138   data->current_feature = tdesc_create_feature (data->tdesc, name);
 139 }
 140
 141 /* Handle the start of a <reg> element.  Fill in the optional
 142    attributes and attach it to the containing feature.  */
 143
 144 static void
 145 tdesc_start_reg (struct gdb_xml_parser *parser,
 146                  const struct gdb_xml_element *element,
 147                  void *user_data, VEC(gdb_xml_value_s) *attributes)
 148 {
 149   struct tdesc_parsing_data *data = user_data;
 150   struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
 151   int ix = 0, length;
 152   char *name, *group, *type;
 153   int bitsize, regnum, save_restore;
 154
 155   length = VEC_length (gdb_xml_value_s, attributes);
 156
 157   name = attrs[ix++].value;
 158   bitsize = * (ULONGEST *) attrs[ix++].value;
 159
 160   if (ix < length && strcmp (attrs[ix].name, "regnum") == 0)
 161     regnum = * (ULONGEST *) attrs[ix++].value;
 162   else
 163     regnum = data->next_regnum;
 164
 165   if (ix < length && strcmp (attrs[ix].name, "type") == 0)
 166     type = attrs[ix++].value;
 167   else
 168     type = "int";
 169
 170   if (ix < length && strcmp (attrs[ix].name, "group") == 0)
 171     group = attrs[ix++].value;
 172   else
 173     group = NULL;
 174
 175   if (ix < length && strcmp (attrs[ix].name, "save-restore") == 0)
 176     save_restore = * (ULONGEST *) attrs[ix++].value;
 177   else
 178     save_restore = 1;
 179
 180   if (strcmp (type, "int") != 0
 181       && strcmp (type, "float") != 0
 182       && strcmp (type, "code_ptr") != 0
 183       && strcmp (type, "data_ptr") != 0
 184       && tdesc_named_type (data->current_feature, type) == NULL)
 185     gdb_xml_error (parser, _("Register \"%s\" has unknown type \"%s\""),
 186                    name, type);
 187
 188   tdesc_create_reg (data->current_feature, name, regnum, save_restore, group,
 189                     bitsize, type);
 190
 191   data->next_regnum = regnum + 1;
 192 }
 193
 194 /* Handle the start of a <union> element.  Initialize the type and
 195    record it with the current feature.  */
 196
 197 static void
 198 tdesc_start_union (struct gdb_xml_parser *parser,
 199                    const struct gdb_xml_element *element,
 200                    void *user_data, VEC(gdb_xml_value_s) *attributes)
 201 {
 202   struct tdesc_parsing_data *data = user_data;
 203   char *id = VEC_index (gdb_xml_value_s, attributes, 0)->value;
 204   struct type *type;
 205
 206   type = init_composite_type (NULL, TYPE_CODE_UNION);
 207   TYPE_NAME (type) = xstrdup (id);
 208   tdesc_record_type (data->current_feature, type);
 209   data->current_union = type;
 210 }
 211
 212 /* Handle the end of a <union> element.  */
 213
 214 static void
 215 tdesc_end_union (struct gdb_xml_parser *parser,
 216                  const struct gdb_xml_element *element,
 217                  void *user_data, const char *body_text)
 218 {
 219   struct tdesc_parsing_data *data = user_data;
 220   int i;
 221
 222   /* If any of the children of this union are vectors, flag the union
 223      as a vector also.  This allows e.g. a union of two vector types
 224      to show up automatically in "info vector".  */
 225   for (i = 0; i < TYPE_NFIELDS (data->current_union); i++)
 226     if (TYPE_VECTOR (TYPE_FIELD_TYPE (data->current_union, i)))
 227       {
 228         TYPE_FLAGS (data->current_union) |= TYPE_FLAG_VECTOR;
 229         break;
 230       }
 231 }
 232
 233 /* Handle the start of a <field> element.  Attach the field to the
 234    current union.  */
 235
 236 static void
 237 tdesc_start_field (struct gdb_xml_parser *parser,
 238                    const struct gdb_xml_element *element,
 239                    void *user_data, VEC(gdb_xml_value_s) *attributes)
 240 {
 241   struct tdesc_parsing_data *data = user_data;
 242   struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
 243   struct type *type, *field_type;
 244   char *field_name, *field_type_id;
 245
 246   field_name = attrs[0].value;
 247   field_type_id = attrs[1].value;
 248
 249   field_type = tdesc_named_type (data->current_feature, field_type_id);
 250   if (field_type == NULL)
 251     gdb_xml_error (parser, _("Union field \"%s\" references undefined "
 252                              "type \"%s\""),
 253                    field_name, field_type_id);
 254
 255   append_composite_type_field (data->current_union, xstrdup (field_name),
 256                                field_type);
 257 }
 258
 259 /* Handle the start of a <vector> element.  Initialize the type and
 260    record it with the current feature.  */
 261
 262 static void
 263 tdesc_start_vector (struct gdb_xml_parser *parser,
 264                     const struct gdb_xml_element *element,
 265                     void *user_data, VEC(gdb_xml_value_s) *attributes)
 266 {
 267   struct tdesc_parsing_data *data = user_data;
 268   struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
 269   struct type *type, *field_type, *range_type;
 270   char *id, *field_type_id;
 271   int count;
 272
 273   id = attrs[0].value;
 274   field_type_id = attrs[1].value;
 275   count = * (ULONGEST *) attrs[2].value;
 276
 277   field_type = tdesc_named_type (data->current_feature, field_type_id);
 278   if (field_type == NULL)
 279     gdb_xml_error (parser, _("Vector \"%s\" references undefined type \"%s\""),
 280                    id, field_type_id);
 281
 282   /* A vector is just an array plus a special flag.  */
 283   range_type = create_range_type (NULL, builtin_type_int, 0, count - 1);
 284   type = create_array_type (NULL, field_type, range_type);
 285   TYPE_NAME (type) = xstrdup (id);
 286
 287   TYPE_FLAGS (type) |= TYPE_FLAG_VECTOR;
 288
 289   tdesc_record_type (data->current_feature, type);
 290 }
 291
 292 /* The elements and attributes of an XML target description.  */
 293
 294 static const struct gdb_xml_attribute field_attributes[] = {
 295   { "name", GDB_XML_AF_NONE, NULL, NULL },
 296   { "type", GDB_XML_AF_NONE, NULL, NULL },
 297   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 298 };
 299
 300 static const struct gdb_xml_element union_children[] = {
 301   { "field", field_attributes, NULL, GDB_XML_EF_REPEATABLE,
 302     tdesc_start_field, NULL },
 303   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 304 };
 305
 306 static const struct gdb_xml_attribute reg_attributes[] = {
 307   { "name", GDB_XML_AF_NONE, NULL, NULL },
 308   { "bitsize", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 309   { "regnum", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },
 310   { "type", GDB_XML_AF_OPTIONAL, NULL, NULL },
 311   { "group", GDB_XML_AF_OPTIONAL, NULL, NULL },
 312   { "save-restore", GDB_XML_AF_OPTIONAL,
 313     gdb_xml_parse_attr_enum, gdb_xml_enums_boolean },
 314   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 315 };
 316
 317 static const struct gdb_xml_attribute union_attributes[] = {
 318   { "id", GDB_XML_AF_NONE, NULL, NULL },
 319   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 320 };
 321
 322 static const struct gdb_xml_attribute vector_attributes[] = {
 323   { "id", GDB_XML_AF_NONE, NULL, NULL },
 324   { "type", GDB_XML_AF_NONE, NULL, NULL },
 325   { "count", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 326   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 327 };
 328
 329 static const struct gdb_xml_attribute feature_attributes[] = {
 330   { "name", GDB_XML_AF_NONE, NULL, NULL },
 331   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 332 };
 333
 334 static const struct gdb_xml_element feature_children[] = {
 335   { "reg", reg_attributes, NULL,
 336     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 337     tdesc_start_reg, NULL },
 338   { "union", union_attributes, union_children,
 339     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 340     tdesc_start_union, tdesc_end_union },
 341   { "vector", vector_attributes, NULL,
 342     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 343     tdesc_start_vector, NULL },
 344   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 345 };
 346
 347 static const struct gdb_xml_attribute target_attributes[] = {
 348   { "version", GDB_XML_AF_NONE, NULL, NULL },
 349   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 350 };
 351
 352 static const struct gdb_xml_element target_children[] = {
 353   { "architecture", NULL, NULL, GDB_XML_EF_OPTIONAL,
 354     NULL, tdesc_end_arch },
 355   { "feature", feature_attributes, feature_children,
 356     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 357     tdesc_start_feature, NULL },
 358   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 359 };
 360
 361 static const struct gdb_xml_element tdesc_elements[] = {
 362   { "target", target_attributes, target_children, GDB_XML_EF_NONE,
 363     tdesc_start_target, NULL },
 364   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 365 };
 366
 367 /* Parse DOCUMENT into a target description and return it.  */
 368
 369 static struct target_desc *
 370 tdesc_parse_xml (const char *document, xml_fetch_another fetcher,
 371                  void *fetcher_baton)
 372 {
 373   struct cleanup *back_to, *result_cleanup;
 374   struct gdb_xml_parser *parser;
 375   struct tdesc_parsing_data data;
 376   struct tdesc_xml_cache *cache;
 377   char *expanded_text;
 378   int ix;
 379
 380   /* Expand all XInclude directives.  */
 381   expanded_text = xml_process_xincludes (_("target description"),
 382                                          document, fetcher, fetcher_baton, 0);
 383   if (expanded_text == NULL)
 384     {
 385       warning (_("Could not load XML target description; ignoring"));
 386       return NULL;
 387     }
 388
 389   /* Check for an exact match in the list of descriptions we have
 390      previously parsed.  strcmp is a slightly inefficient way to
 391      do this; an SHA-1 checksum would work as well.  */
 392   for (ix = 0; VEC_iterate (tdesc_xml_cache_s, xml_cache, ix, cache); ix++)
 393     if (strcmp (cache->xml_document, expanded_text) == 0)
 394       {
 395        xfree (expanded_text);
 396        return cache->tdesc;
 397       }
 398
 399   back_to = make_cleanup (null_cleanup, NULL);
 400   parser = gdb_xml_create_parser_and_cleanup (_("target description"),
 401                                               tdesc_elements, &data);
 402   gdb_xml_use_dtd (parser, "gdb-target.dtd");
 403
 404   memset (&data, 0, sizeof (struct tdesc_parsing_data));
 405   data.tdesc = allocate_target_description ();
 406   result_cleanup = make_cleanup_free_target_description (data.tdesc);
 407   make_cleanup (xfree, expanded_text);
 408
 409   if (gdb_xml_parse (parser, expanded_text) == 0)
 410     {
 411       /* Parsed successfully.  */
 412       struct tdesc_xml_cache new_cache;
 413
 414       new_cache.xml_document = expanded_text;
 415       new_cache.tdesc = data.tdesc;
 416       VEC_safe_push (tdesc_xml_cache_s, xml_cache, &new_cache);
 417       discard_cleanups (result_cleanup);
 418       do_cleanups (back_to);
 419       return data.tdesc;
 420     }
 421   else
 422     {
 423       warning (_("Could not load XML target description; ignoring"));
 424       do_cleanups (back_to);
 425       return NULL;
 426     }
 427 }
 428 #endif /* HAVE_LIBEXPAT */
 429 \f
 430
 431 /* Close FILE.  */
 432
 433 static void
 434 do_cleanup_fclose (void *file)
 435 {
 436   fclose (file);
 437 }
 438
 439 /* Open FILENAME, read all its text into memory, close it, and return
 440    the text.  If something goes wrong, return NULL and warn.  */
 441
 442 static char *
 443 fetch_xml_from_file (const char *filename, void *baton)
 444 {
 445   const char *dirname = baton;
 446   FILE *file;
 447   struct cleanup *back_to;
 448   char *text;
 449   size_t len, offset;
 450
 451   if (dirname && *dirname)
 452     {
 453       char *fullname = concat (dirname, "/", filename, NULL);
 454       if (fullname == NULL)
 455         nomem (0);
 456       file = fopen (fullname, FOPEN_RT);
 457       xfree (fullname);
 458     }
 459   else
 460     file = fopen (filename, FOPEN_RT);
 461
 462   if (file == NULL)
 463     return NULL;
 464
 465   back_to = make_cleanup (do_cleanup_fclose, file);
 466
 467   /* Read in the whole file, one chunk at a time.  */
 468   len = 4096;
 469   offset = 0;
 470   text = xmalloc (len);
 471   make_cleanup (free_current_contents, &text);
 472   while (1)
 473     {
 474       size_t bytes_read;
 475
 476       /* Continue reading where the last read left off.  Leave at least
 477          one byte so that we can NUL-terminate the result.  */
 478       bytes_read = fread (text + offset, 1, len - offset - 1, file);
 479       if (ferror (file))
 480         {
 481           warning (_("Read error from \"%s\""), filename);
 482           do_cleanups (back_to);
 483           return NULL;
 484         }
 485
 486       offset += bytes_read;
 487
 488       if (feof (file))
 489         break;
 490
 491       len = len * 2;
 492       text = xrealloc (text, len);
 493     }
 494
 495   fclose (file);
 496   discard_cleanups (back_to);
 497
 498   text[offset] = '\0';
 499   return text;
 500 }
 501
 502 /* Read an XML target description from FILENAME.  Parse it, and return
 503    the parsed description.  */
 504
 505 const struct target_desc *
 506 file_read_description_xml (const char *filename)
 507 {
 508   struct target_desc *tdesc;
 509   char *tdesc_str;
 510   struct cleanup *back_to;
 511   char *dirname;
 512
 513   tdesc_str = fetch_xml_from_file (filename, NULL);
 514   if (tdesc_str == NULL)
 515     {
 516       warning (_("Could not open \"%s\""), filename);
 517       return NULL;
 518     }
 519
 520   back_to = make_cleanup (xfree, tdesc_str);
 521
 522   dirname = ldirname (filename);
 523   if (dirname != NULL)
 524     make_cleanup (xfree, dirname);
 525
 526   tdesc = tdesc_parse_xml (tdesc_str, fetch_xml_from_file, dirname);
 527   do_cleanups (back_to);
 528
 529   return tdesc;
 530 }
 531
 532 /* Read a string representation of available features from the target,
 533    using TARGET_OBJECT_AVAILABLE_FEATURES.  The returned string is
 534    malloc allocated and NUL-terminated.  NAME should be a non-NULL
 535    string identifying the XML document we want; the top level document
 536    is "target.xml".  Other calls may be performed for the DTD or
 537    for <xi:include>.  */
 538
 539 static char *
 540 fetch_available_features_from_target (const char *name, void *baton_)
 541 {
 542   struct target_ops *ops = baton_;
 543
 544   /* Read this object as a string.  This ensures that a NUL
 545      terminator is added.  */
 546   return target_read_stralloc (ops,
 547                                TARGET_OBJECT_AVAILABLE_FEATURES,
 548                                name);
 549 }
 550 \f
 551
 552 /* Read an XML target description using OPS.  Parse it, and return the
 553    parsed description.  */
 554
 555 const struct target_desc *
 556 target_read_description_xml (struct target_ops *ops)
 557 {
 558   struct target_desc *tdesc;
 559   char *tdesc_str;
 560   struct cleanup *back_to;
 561
 562   tdesc_str = fetch_available_features_from_target ("target.xml", ops);
 563   if (tdesc_str == NULL)
 564     return NULL;
 565
 566   back_to = make_cleanup (xfree, tdesc_str);
 567   tdesc = tdesc_parse_xml (tdesc_str,
 568                            fetch_available_features_from_target,
 569                            ops);
 570   do_cleanups (back_to);
 571
 572   return tdesc;
 573 }