gdb/xml-tdesc.c

   1 /* XML target description support for GDB.
   2
   3    Copyright (C) 2006-2017 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 #include "filenames.h"
  29 #include <unordered_map>
  30 #include <string>
  31
  32 /* Maximum sizes.
  33    This is just to catch obviously wrong values.  */
  34 #define MAX_FIELD_SIZE 65536
  35 #define MAX_FIELD_BITSIZE (MAX_FIELD_SIZE * TARGET_CHAR_BIT)
  36 #define MAX_VECTOR_SIZE 65536
  37
  38 #if !defined(HAVE_LIBEXPAT)
  39
  40 /* Parse DOCUMENT into a target description.  Or don't, since we don't have
  41    an XML parser.  */
  42
  43 static struct target_desc *
  44 tdesc_parse_xml (const char *document, xml_fetch_another fetcher,
  45                  void *fetcher_baton)
  46 {
  47   static int have_warned;
  48
  49   if (!have_warned)
  50     {
  51       have_warned = 1;
  52       warning (_("Can not parse XML target description; XML support was "
  53                  "disabled at compile time"));
  54     }
  55
  56   return NULL;
  57 }
  58
  59 #else /* HAVE_LIBEXPAT */
  60
  61 /* A record of every XML description we have parsed.  We never discard
  62    old descriptions, because we never discard gdbarches.  As long as we
  63    have a gdbarch referencing this description, we want to have a copy
  64    of it here, so that if we parse the same XML document again we can
  65    return the same "struct target_desc *"; if they are not singletons,
  66    then we will create unnecessary duplicate gdbarches.  See
  67    gdbarch_list_lookup_by_info.  */
  68
  69 static std::unordered_map<std::string, target_desc *> xml_cache;
  70
  71 /* Callback data for target description parsing.  */
  72
  73 struct tdesc_parsing_data
  74 {
  75   /* The target description we are building.  */
  76   struct target_desc *tdesc;
  77
  78   /* The target feature we are currently parsing, or last parsed.  */
  79   struct tdesc_feature *current_feature;
  80
  81   /* The register number to use for the next register we see, if
  82      it does not have its own.  This starts at zero.  */
  83   int next_regnum;
  84
  85   /* The struct or union we are currently parsing, or last parsed.  */
  86   struct tdesc_type *current_type;
  87
  88   /* The byte size of the current struct/flags type, if specified.  Zero
  89      if not specified.  Flags values must specify a size.  */
  90   int current_type_size;
  91 };
  92
  93 /* Handle the end of an <architecture> element and its value.  */
  94
  95 static void
  96 tdesc_end_arch (struct gdb_xml_parser *parser,
  97                 const struct gdb_xml_element *element,
  98                 void *user_data, const char *body_text)
  99 {
 100   struct tdesc_parsing_data *data = (struct tdesc_parsing_data *) user_data;
 101   const struct bfd_arch_info *arch;
 102
 103   arch = bfd_scan_arch (body_text);
 104   if (arch == NULL)
 105     gdb_xml_error (parser, _("Target description specified unknown "
 106                              "architecture \"%s\""), body_text);
 107   set_tdesc_architecture (data->tdesc, arch);
 108 }
 109
 110 /* Handle the end of an <osabi> element and its value.  */
 111
 112 static void
 113 tdesc_end_osabi (struct gdb_xml_parser *parser,
 114                  const struct gdb_xml_element *element,
 115                  void *user_data, const char *body_text)
 116 {
 117   struct tdesc_parsing_data *data = (struct tdesc_parsing_data *) user_data;
 118   enum gdb_osabi osabi;
 119
 120   osabi = osabi_from_tdesc_string (body_text);
 121   if (osabi == GDB_OSABI_UNKNOWN)
 122     warning (_("Target description specified unknown osabi \"%s\""),
 123              body_text);
 124   else
 125     set_tdesc_osabi (data->tdesc, osabi);
 126 }
 127
 128 /* Handle the end of a <compatible> element and its value.  */
 129
 130 static void
 131 tdesc_end_compatible (struct gdb_xml_parser *parser,
 132                       const struct gdb_xml_element *element,
 133                       void *user_data, const char *body_text)
 134 {
 135   struct tdesc_parsing_data *data = (struct tdesc_parsing_data *) user_data;
 136   const struct bfd_arch_info *arch;
 137
 138   arch = bfd_scan_arch (body_text);
 139   tdesc_add_compatible (data->tdesc, arch);
 140 }
 141
 142 /* Handle the start of a <target> element.  */
 143
 144 static void
 145 tdesc_start_target (struct gdb_xml_parser *parser,
 146                     const struct gdb_xml_element *element,
 147                     void *user_data, VEC(gdb_xml_value_s) *attributes)
 148 {
 149   char *version = (char *) xml_find_attribute (attributes, "version")->value;
 150
 151   if (strcmp (version, "1.0") != 0)
 152     gdb_xml_error (parser,
 153                    _("Target description has unsupported version \"%s\""),
 154                    version);
 155 }
 156
 157 /* Handle the start of a <feature> element.  */
 158
 159 static void
 160 tdesc_start_feature (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 = (struct tdesc_parsing_data *) user_data;
 165   char *name = (char *) xml_find_attribute (attributes, "name")->value;
 166
 167   data->current_feature = tdesc_create_feature (data->tdesc, name);
 168 }
 169
 170 /* Handle the start of a <reg> element.  Fill in the optional
 171    attributes and attach it to the containing feature.  */
 172
 173 static void
 174 tdesc_start_reg (struct gdb_xml_parser *parser,
 175                  const struct gdb_xml_element *element,
 176                  void *user_data, VEC(gdb_xml_value_s) *attributes)
 177 {
 178   struct tdesc_parsing_data *data = (struct tdesc_parsing_data *) user_data;
 179   struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
 180   int ix = 0, length;
 181   char *name, *group;
 182   const char *type;
 183   int bitsize, regnum, save_restore;
 184
 185   length = VEC_length (gdb_xml_value_s, attributes);
 186
 187   name = (char *) attrs[ix++].value;
 188   bitsize = * (ULONGEST *) attrs[ix++].value;
 189
 190   if (ix < length && strcmp (attrs[ix].name, "regnum") == 0)
 191     regnum = * (ULONGEST *) attrs[ix++].value;
 192   else
 193     regnum = data->next_regnum;
 194
 195   if (ix < length && strcmp (attrs[ix].name, "type") == 0)
 196     type = (char *) attrs[ix++].value;
 197   else
 198     type = "int";
 199
 200   if (ix < length && strcmp (attrs[ix].name, "group") == 0)
 201     group = (char *) attrs[ix++].value;
 202   else
 203     group = NULL;
 204
 205   if (ix < length && strcmp (attrs[ix].name, "save-restore") == 0)
 206     save_restore = * (ULONGEST *) attrs[ix++].value;
 207   else
 208     save_restore = 1;
 209
 210   if (strcmp (type, "int") != 0
 211       && strcmp (type, "float") != 0
 212       && tdesc_named_type (data->current_feature, type) == NULL)
 213     gdb_xml_error (parser, _("Register \"%s\" has unknown type \"%s\""),
 214                    name, type);
 215
 216   tdesc_create_reg (data->current_feature, name, regnum, save_restore, group,
 217                     bitsize, type);
 218
 219   data->next_regnum = regnum + 1;
 220 }
 221
 222 /* Handle the start of a <union> element.  Initialize the type and
 223    record it with the current feature.  */
 224
 225 static void
 226 tdesc_start_union (struct gdb_xml_parser *parser,
 227                    const struct gdb_xml_element *element,
 228                    void *user_data, VEC(gdb_xml_value_s) *attributes)
 229 {
 230   struct tdesc_parsing_data *data = (struct tdesc_parsing_data *) user_data;
 231   char *id = (char *) xml_find_attribute (attributes, "id")->value;
 232
 233   data->current_type = tdesc_create_union (data->current_feature, id);
 234   data->current_type_size = 0;
 235 }
 236
 237 /* Handle the start of a <struct> element.  Initialize the type and
 238    record it with the current feature.  */
 239
 240 static void
 241 tdesc_start_struct (struct gdb_xml_parser *parser,
 242                    const struct gdb_xml_element *element,
 243                    void *user_data, VEC(gdb_xml_value_s) *attributes)
 244 {
 245   struct tdesc_parsing_data *data = (struct tdesc_parsing_data *) user_data;
 246   char *id = (char *) xml_find_attribute (attributes, "id")->value;
 247   struct tdesc_type *type;
 248   struct gdb_xml_value *attr;
 249
 250   type = tdesc_create_struct (data->current_feature, id);
 251   data->current_type = type;
 252   data->current_type_size = 0;
 253
 254   attr = xml_find_attribute (attributes, "size");
 255   if (attr != NULL)
 256     {
 257       ULONGEST size = * (ULONGEST *) attr->value;
 258
 259       if (size > MAX_FIELD_SIZE)
 260         {
 261           gdb_xml_error (parser,
 262                          _("Struct size %s is larger than maximum (%d)"),
 263                          pulongest (size), MAX_FIELD_SIZE);
 264         }
 265       tdesc_set_struct_size (type, size);
 266       data->current_type_size = size;
 267     }
 268 }
 269
 270 static void
 271 tdesc_start_flags (struct gdb_xml_parser *parser,
 272                    const struct gdb_xml_element *element,
 273                    void *user_data, VEC(gdb_xml_value_s) *attributes)
 274 {
 275   struct tdesc_parsing_data *data = (struct tdesc_parsing_data *) user_data;
 276   char *id = (char *) xml_find_attribute (attributes, "id")->value;
 277   ULONGEST size = * (ULONGEST *)
 278     xml_find_attribute (attributes, "size")->value;
 279   struct tdesc_type *type;
 280
 281   if (size > MAX_FIELD_SIZE)
 282     {
 283       gdb_xml_error (parser,
 284                      _("Flags size %s is larger than maximum (%d)"),
 285                      pulongest (size), MAX_FIELD_SIZE);
 286     }
 287   type = tdesc_create_flags (data->current_feature, id, size);
 288
 289   data->current_type = type;
 290   data->current_type_size = size;
 291 }
 292
 293 static void
 294 tdesc_start_enum (struct gdb_xml_parser *parser,
 295                   const struct gdb_xml_element *element,
 296                   void *user_data, VEC(gdb_xml_value_s) *attributes)
 297 {
 298   struct tdesc_parsing_data *data = (struct tdesc_parsing_data *) user_data;
 299   char *id = (char *) xml_find_attribute (attributes, "id")->value;
 300   int size = * (ULONGEST *)
 301     xml_find_attribute (attributes, "size")->value;
 302   struct tdesc_type *type;
 303
 304   if (size > MAX_FIELD_SIZE)
 305     {
 306       gdb_xml_error (parser,
 307                      _("Enum size %s is larger than maximum (%d)"),
 308                      pulongest (size), MAX_FIELD_SIZE);
 309     }
 310   type = tdesc_create_enum (data->current_feature, id, size);
 311
 312   data->current_type = type;
 313   data->current_type_size = 0;
 314 }
 315
 316 /* Handle the start of a <field> element.  Attach the field to the
 317    current struct, union or flags.  */
 318
 319 static void
 320 tdesc_start_field (struct gdb_xml_parser *parser,
 321                    const struct gdb_xml_element *element,
 322                    void *user_data, VEC(gdb_xml_value_s) *attributes)
 323 {
 324   struct tdesc_parsing_data *data = (struct tdesc_parsing_data *) user_data;
 325   struct gdb_xml_value *attr;
 326   struct tdesc_type *field_type;
 327   char *field_name, *field_type_id;
 328   int start, end;
 329
 330   field_name = (char *) xml_find_attribute (attributes, "name")->value;
 331
 332   attr = xml_find_attribute (attributes, "type");
 333   if (attr != NULL)
 334     {
 335       field_type_id = (char *) attr->value;
 336       field_type = tdesc_named_type (data->current_feature, field_type_id);
 337     }
 338   else
 339     {
 340       field_type_id = NULL;
 341       field_type = NULL;
 342     }
 343
 344   attr = xml_find_attribute (attributes, "start");
 345   if (attr != NULL)
 346     {
 347       ULONGEST ul_start = * (ULONGEST *) attr->value;
 348
 349       if (ul_start > MAX_FIELD_BITSIZE)
 350         {
 351           gdb_xml_error (parser,
 352                          _("Field start %s is larger than maximum (%d)"),
 353                          pulongest (ul_start), MAX_FIELD_BITSIZE);
 354         }
 355       start = ul_start;
 356     }
 357   else
 358     start = -1;
 359
 360   attr = xml_find_attribute (attributes, "end");
 361   if (attr != NULL)
 362     {
 363       ULONGEST ul_end = * (ULONGEST *) attr->value;
 364
 365       if (ul_end > MAX_FIELD_BITSIZE)
 366         {
 367           gdb_xml_error (parser,
 368                          _("Field end %s is larger than maximum (%d)"),
 369                          pulongest (ul_end), MAX_FIELD_BITSIZE);
 370         }
 371       end = ul_end;
 372     }
 373   else
 374     end = -1;
 375
 376   if (start != -1)
 377     {
 378       struct tdesc_type *t = data->current_type;
 379
 380       /* Older versions of gdb can't handle elided end values.
 381          Stick with that for now, to help ensure backward compatibility.
 382          E.g., If a newer gdbserver is talking to an older gdb.  */
 383       if (end == -1)
 384         gdb_xml_error (parser, _("Missing end value"));
 385
 386       if (data->current_type_size == 0)
 387         gdb_xml_error (parser,
 388                        _("Bitfields must live in explicitly sized types"));
 389
 390       if (field_type_id != NULL
 391           && strcmp (field_type_id, "bool") == 0
 392           && start != end)
 393         {
 394           gdb_xml_error (parser,
 395                          _("Boolean fields must be one bit in size"));
 396         }
 397
 398       if (end >= 64)
 399         gdb_xml_error (parser,
 400                        _("Bitfield \"%s\" goes past "
 401                          "64 bits (unsupported)"),
 402                        field_name);
 403
 404       /* Assume that the bit numbering in XML is "lsb-zero".  Most
 405          architectures other than PowerPC use this ordering.  In the
 406          future, we can add an XML tag to indicate "msb-zero" numbering.  */
 407       if (start > end)
 408         gdb_xml_error (parser, _("Bitfield \"%s\" has start after end"),
 409                        field_name);
 410       if (end >= data->current_type_size * TARGET_CHAR_BIT)
 411         gdb_xml_error (parser, _("Bitfield \"%s\" does not fit in struct"),
 412                        field_name);
 413
 414       if (field_type != NULL)
 415         tdesc_add_typed_bitfield (t, field_name, start, end, field_type);
 416       else if (start == end)
 417         tdesc_add_flag (t, start, field_name);
 418       else
 419         tdesc_add_bitfield (t, field_name, start, end);
 420     }
 421   else if (start == -1 && end != -1)
 422     gdb_xml_error (parser, _("End specified but not start"));
 423   else if (field_type_id != NULL)
 424     {
 425       /* TDESC_TYPE_FLAGS values are explicitly sized, so the following test
 426          catches adding non-bitfield types to flags as well.  */
 427       if (data->current_type_size != 0)
 428         gdb_xml_error (parser,
 429                        _("Explicitly sized type cannot "
 430                          "contain non-bitfield \"%s\""),
 431                        field_name);
 432
 433       if (field_type == NULL)
 434         gdb_xml_error (parser, _("Field \"%s\" references undefined "
 435                                  "type \"%s\""),
 436                        field_name, field_type_id);
 437
 438       tdesc_add_field (data->current_type, field_name, field_type);
 439     }
 440   else
 441     gdb_xml_error (parser, _("Field \"%s\" has neither type nor bit position"),
 442                    field_name);
 443 }
 444
 445 /* Handle the start of an <evalue> element.  Attach the value to the
 446    current enum.  */
 447
 448 static void
 449 tdesc_start_enum_value (struct gdb_xml_parser *parser,
 450                         const struct gdb_xml_element *element,
 451                         void *user_data, VEC(gdb_xml_value_s) *attributes)
 452 {
 453   struct tdesc_parsing_data *data = (struct tdesc_parsing_data *) user_data;
 454   struct gdb_xml_value *attr;
 455   char *field_name;
 456   ULONGEST ul_value;
 457   int value;
 458
 459   field_name = (char *) xml_find_attribute (attributes, "name")->value;
 460
 461   attr = xml_find_attribute (attributes, "value");
 462   ul_value = * (ULONGEST *) attr->value;
 463   if (ul_value > INT_MAX)
 464     {
 465       gdb_xml_error (parser,
 466                      _("Enum value %s is larger than maximum (%d)"),
 467                      pulongest (ul_value), INT_MAX);
 468     }
 469   value = ul_value;
 470
 471   tdesc_add_enum_value (data->current_type, value, field_name);
 472 }
 473
 474 /* Handle the start of a <vector> element.  Initialize the type and
 475    record it with the current feature.  */
 476
 477 static void
 478 tdesc_start_vector (struct gdb_xml_parser *parser,
 479                     const struct gdb_xml_element *element,
 480                     void *user_data, VEC(gdb_xml_value_s) *attributes)
 481 {
 482   struct tdesc_parsing_data *data = (struct tdesc_parsing_data *) user_data;
 483   struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);
 484   struct tdesc_type *field_type;
 485   char *id, *field_type_id;
 486   ULONGEST count;
 487
 488   id = (char *) attrs[0].value;
 489   field_type_id = (char *) attrs[1].value;
 490   count = * (ULONGEST *) attrs[2].value;
 491
 492   if (count > MAX_VECTOR_SIZE)
 493     {
 494       gdb_xml_error (parser,
 495                      _("Vector size %s is larger than maximum (%d)"),
 496                      pulongest (count), MAX_VECTOR_SIZE);
 497     }
 498
 499   field_type = tdesc_named_type (data->current_feature, field_type_id);
 500   if (field_type == NULL)
 501     gdb_xml_error (parser, _("Vector \"%s\" references undefined type \"%s\""),
 502                    id, field_type_id);
 503
 504   tdesc_create_vector (data->current_feature, id, field_type, count);
 505 }
 506
 507 /* The elements and attributes of an XML target description.  */
 508
 509 static const struct gdb_xml_attribute field_attributes[] = {
 510   { "name", GDB_XML_AF_NONE, NULL, NULL },
 511   { "type", GDB_XML_AF_OPTIONAL, NULL, NULL },
 512   { "start", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },
 513   { "end", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },
 514   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 515 };
 516
 517 static const struct gdb_xml_attribute enum_value_attributes[] = {
 518   { "name", GDB_XML_AF_NONE, NULL, NULL },
 519   { "value", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },
 520   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 521 };
 522
 523 static const struct gdb_xml_element struct_union_children[] = {
 524   { "field", field_attributes, NULL, GDB_XML_EF_REPEATABLE,
 525     tdesc_start_field, NULL },
 526   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 527 };
 528
 529 static const struct gdb_xml_element enum_children[] = {
 530   { "evalue", enum_value_attributes, NULL, GDB_XML_EF_REPEATABLE,
 531     tdesc_start_enum_value, NULL },
 532   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 533 };
 534
 535 static const struct gdb_xml_attribute reg_attributes[] = {
 536   { "name", GDB_XML_AF_NONE, NULL, NULL },
 537   { "bitsize", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 538   { "regnum", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },
 539   { "type", GDB_XML_AF_OPTIONAL, NULL, NULL },
 540   { "group", GDB_XML_AF_OPTIONAL, NULL, NULL },
 541   { "save-restore", GDB_XML_AF_OPTIONAL,
 542     gdb_xml_parse_attr_enum, gdb_xml_enums_boolean },
 543   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 544 };
 545
 546 static const struct gdb_xml_attribute struct_union_attributes[] = {
 547   { "id", GDB_XML_AF_NONE, NULL, NULL },
 548   { "size", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL},
 549   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 550 };
 551
 552 static const struct gdb_xml_attribute flags_attributes[] = {
 553   { "id", GDB_XML_AF_NONE, NULL, NULL },
 554   { "size", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL},
 555   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 556 };
 557
 558 static const struct gdb_xml_attribute enum_attributes[] = {
 559   { "id", GDB_XML_AF_NONE, NULL, NULL },
 560   { "size", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL},
 561   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 562 };
 563
 564 static const struct gdb_xml_attribute vector_attributes[] = {
 565   { "id", GDB_XML_AF_NONE, NULL, NULL },
 566   { "type", GDB_XML_AF_NONE, NULL, NULL },
 567   { "count", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },
 568   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 569 };
 570
 571 static const struct gdb_xml_attribute feature_attributes[] = {
 572   { "name", GDB_XML_AF_NONE, NULL, NULL },
 573   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 574 };
 575
 576 static const struct gdb_xml_element feature_children[] = {
 577   { "reg", reg_attributes, NULL,
 578     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 579     tdesc_start_reg, NULL },
 580   { "struct", struct_union_attributes, struct_union_children,
 581     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 582     tdesc_start_struct, NULL },
 583   { "union", struct_union_attributes, struct_union_children,
 584     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 585     tdesc_start_union, NULL },
 586   { "flags", flags_attributes, struct_union_children,
 587     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 588     tdesc_start_flags, NULL },
 589   { "enum", enum_attributes, enum_children,
 590     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 591     tdesc_start_enum, NULL },
 592   { "vector", vector_attributes, NULL,
 593     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 594     tdesc_start_vector, NULL },
 595   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 596 };
 597
 598 static const struct gdb_xml_attribute target_attributes[] = {
 599   { "version", GDB_XML_AF_NONE, NULL, NULL },
 600   { NULL, GDB_XML_AF_NONE, NULL, NULL }
 601 };
 602
 603 static const struct gdb_xml_element target_children[] = {
 604   { "architecture", NULL, NULL, GDB_XML_EF_OPTIONAL,
 605     NULL, tdesc_end_arch },
 606   { "osabi", NULL, NULL, GDB_XML_EF_OPTIONAL,
 607     NULL, tdesc_end_osabi },
 608   { "compatible", NULL, NULL, GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 609     NULL, tdesc_end_compatible },
 610   { "feature", feature_attributes, feature_children,
 611     GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,
 612     tdesc_start_feature, NULL },
 613   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 614 };
 615
 616 static const struct gdb_xml_element tdesc_elements[] = {
 617   { "target", target_attributes, target_children, GDB_XML_EF_NONE,
 618     tdesc_start_target, NULL },
 619   { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
 620 };
 621
 622 /* Parse DOCUMENT into a target description and return it.  */
 623
 624 static struct target_desc *
 625 tdesc_parse_xml (const char *document, xml_fetch_another fetcher,
 626                  void *fetcher_baton)
 627 {
 628   struct tdesc_parsing_data data;
 629
 630   /* Expand all XInclude directives.  */
 631   std::string expanded_text;
 632
 633   if (!xml_process_xincludes (expanded_text,
 634                               _("target description"),
 635                               document, fetcher, fetcher_baton, 0))
 636     {
 637       warning (_("Could not load XML target description; ignoring"));
 638       return NULL;
 639     }
 640
 641   /* Check for an exact match in the list of descriptions we have
 642      previously parsed.  */
 643   const auto it = xml_cache.find (expanded_text);
 644   if (it != xml_cache.end ())
 645     return it->second;
 646
 647   memset (&data, 0, sizeof (struct tdesc_parsing_data));
 648   data.tdesc = allocate_target_description ();
 649   struct cleanup *result_cleanup
 650     = make_cleanup_free_target_description (data.tdesc);
 651
 652   if (gdb_xml_parse_quick (_("target description"), "gdb-target.dtd",
 653                            tdesc_elements, expanded_text.c_str (), &data) == 0)
 654     {
 655       /* Parsed successfully.  */
 656       xml_cache.emplace (std::move (expanded_text), data.tdesc);
 657       discard_cleanups (result_cleanup);
 658       return data.tdesc;
 659     }
 660   else
 661     {
 662       warning (_("Could not load XML target description; ignoring"));
 663       do_cleanups (result_cleanup);
 664       return NULL;
 665     }
 666 }
 667 #endif /* HAVE_LIBEXPAT */
 668 \f
 669
 670 /* Read an XML target description from FILENAME.  Parse it, and return
 671    the parsed description.  */
 672
 673 const struct target_desc *
 674 file_read_description_xml (const char *filename)
 675 {
 676   struct target_desc *tdesc;
 677   char *tdesc_str;
 678   struct cleanup *back_to;
 679
 680   tdesc_str = xml_fetch_content_from_file (filename, NULL);
 681   if (tdesc_str == NULL)
 682     {
 683       warning (_("Could not open \"%s\""), filename);
 684       return NULL;
 685     }
 686
 687   back_to = make_cleanup (xfree, tdesc_str);
 688
 689   tdesc = tdesc_parse_xml (tdesc_str, xml_fetch_content_from_file,
 690                            (void *) ldirname (filename).c_str ());
 691   do_cleanups (back_to);
 692
 693   return tdesc;
 694 }
 695
 696 /* Read a string representation of available features from the target,
 697    using TARGET_OBJECT_AVAILABLE_FEATURES.  The returned string is
 698    malloc allocated and NUL-terminated.  NAME should be a non-NULL
 699    string identifying the XML document we want; the top level document
 700    is "target.xml".  Other calls may be performed for the DTD or
 701    for <xi:include>.  */
 702
 703 static char *
 704 fetch_available_features_from_target (const char *name, void *baton_)
 705 {
 706   struct target_ops *ops = (struct target_ops *) baton_;
 707
 708   /* Read this object as a string.  This ensures that a NUL
 709      terminator is added.  */
 710   return target_read_stralloc (ops,
 711                                TARGET_OBJECT_AVAILABLE_FEATURES,
 712                                name);
 713 }
 714 \f
 715
 716 /* Read an XML target description using OPS.  Parse it, and return the
 717    parsed description.  */
 718
 719 const struct target_desc *
 720 target_read_description_xml (struct target_ops *ops)
 721 {
 722   struct target_desc *tdesc;
 723   char *tdesc_str;
 724   struct cleanup *back_to;
 725
 726   tdesc_str = fetch_available_features_from_target ("target.xml", ops);
 727   if (tdesc_str == NULL)
 728     return NULL;
 729
 730   back_to = make_cleanup (xfree, tdesc_str);
 731   tdesc = tdesc_parse_xml (tdesc_str,
 732                            fetch_available_features_from_target,
 733                            ops);
 734   do_cleanups (back_to);
 735
 736   return tdesc;
 737 }
 738
 739 /* Fetches an XML target description using OPS,  processing
 740    includes, but not parsing it.  Used to dump whole tdesc
 741    as a single XML file.  */
 742
 743 gdb::optional<std::string>
 744 target_fetch_description_xml (struct target_ops *ops)
 745 {
 746 #if !defined(HAVE_LIBEXPAT)
 747   static int have_warned;
 748
 749   if (!have_warned)
 750     {
 751       have_warned = 1;
 752       warning (_("Can not fetch XML target description; XML support was "
 753                  "disabled at compile time"));
 754     }
 755
 756   return {};
 757 #else
 758   struct target_desc *tdesc;
 759
 760   gdb::unique_xmalloc_ptr<char>
 761     tdesc_str (fetch_available_features_from_target ("target.xml", ops));
 762   if (tdesc_str == NULL)
 763     return {};
 764
 765   std::string output;
 766   if (!xml_process_xincludes (output,
 767                               _("target description"),
 768                               tdesc_str.get (),
 769                               fetch_available_features_from_target, ops, 0))
 770     {
 771       warning (_("Could not load XML target description; ignoring"));
 772       return {};
 773     }
 774   return output;
 775 #endif
 776 }