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