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/* XML target description support for GDB.

   Copyright (C) 2006, 2008, 2009, 2010 Free Software Foundation, Inc.

   Contributed by CodeSourcery.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3 of the License, or

   (at your option) any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"

#include "target.h"

#include "target-descriptions.h"

#include "xml-support.h"

#include "xml-tdesc.h"

#include "osabi.h"

#include "filenames.h"

#include "gdb_assert.h"

#if !defined(HAVE_LIBEXPAT)

/* Parse DOCUMENT into a target description.  Or don't, since we don't have

   an XML parser.  */

static struct target_desc *

tdesc_parse_xml (const char *document, xml_fetch_another fetcher,

                 void *fetcher_baton)

{

  static int have_warned;

  if (!have_warned)

    {

      have_warned = 1;

      warning (_("Can not parse XML target description; XML support was "

                 "disabled at compile time"));

    }

  return NULL;

}

#else /* HAVE_LIBEXPAT */

/* A record of every XML description we have parsed.  We never discard

   old descriptions, because we never discard gdbarches.  As long as we

   have a gdbarch referencing this description, we want to have a copy

   of it here, so that if we parse the same XML document again we can

   return the same "struct target_desc *"; if they are not singletons,

   then we will create unnecessary duplicate gdbarches.  See

   gdbarch_list_lookup_by_info.  */

struct tdesc_xml_cache

{

  const char *xml_document;

  struct target_desc *tdesc;

};

typedef struct tdesc_xml_cache tdesc_xml_cache_s;

DEF_VEC_O(tdesc_xml_cache_s);

static VEC(tdesc_xml_cache_s) *xml_cache;

/* Callback data for target description parsing.  */

struct tdesc_parsing_data

{

  /* The target description we are building.  */

  struct target_desc *tdesc;

  /* The target feature we are currently parsing, or last parsed.  */

  struct tdesc_feature *current_feature;

  /* The register number to use for the next register we see, if

     it does not have its own.  This starts at zero.  */

  int next_regnum;

  /* The struct or union we are currently parsing, or last parsed.  */

  struct tdesc_type *current_type;

  /* The byte size of the current struct type, if specified.  Zero

     if not specified.  */

  int current_type_size;

  /* Whether the current type is a flags type.  */

  int current_type_is_flags;

};

/* Handle the end of an <architecture> element and its value.  */

static void

tdesc_end_arch (struct gdb_xml_parser *parser,

                const struct gdb_xml_element *element,

                void *user_data, const char *body_text)

{

  struct tdesc_parsing_data *data = user_data;

  const struct bfd_arch_info *arch;

  arch = bfd_scan_arch (body_text);

  if (arch == NULL)

    gdb_xml_error (parser, _("Target description specified unknown "

                             "architecture \"%s\""), body_text);

  set_tdesc_architecture (data->tdesc, arch);

}

/* Handle the end of an <osabi> element and its value.  */

static void

tdesc_end_osabi (struct gdb_xml_parser *parser,

                 const struct gdb_xml_element *element,

                 void *user_data, const char *body_text)

{

  struct tdesc_parsing_data *data = user_data;

  enum gdb_osabi osabi;

  osabi = osabi_from_tdesc_string (body_text);

  if (osabi == GDB_OSABI_UNKNOWN)

    warning (_("Target description specified unknown osabi \"%s\""),

             body_text);

  else

    set_tdesc_osabi (data->tdesc, osabi);

}

/* Handle the end of a <compatible> element and its value.  */

static void

tdesc_end_compatible (struct gdb_xml_parser *parser,

                      const struct gdb_xml_element *element,

                      void *user_data, const char *body_text)

{

  struct tdesc_parsing_data *data = user_data;

  const struct bfd_arch_info *arch;

  arch = bfd_scan_arch (body_text);

  tdesc_add_compatible (data->tdesc, arch);

}

/* Handle the start of a <target> element.  */

static void

tdesc_start_target (struct gdb_xml_parser *parser,

                    const struct gdb_xml_element *element,

                    void *user_data, VEC(gdb_xml_value_s) *attributes)

{

  char *version = VEC_index (gdb_xml_value_s, attributes, 0)->value;

  if (strcmp (version, "1.0") != 0)

    gdb_xml_error (parser,

                   _("Target description has unsupported version \"%s\""),

                   version);

}

/* Handle the start of a <feature> element.  */

static void

tdesc_start_feature (struct gdb_xml_parser *parser,

                     const struct gdb_xml_element *element,

                     void *user_data, VEC(gdb_xml_value_s) *attributes)

{

  struct tdesc_parsing_data *data = user_data;

  char *name = VEC_index (gdb_xml_value_s, attributes, 0)->value;

  data->current_feature = tdesc_create_feature (data->tdesc, name);

}

/* Handle the start of a <reg> element.  Fill in the optional

   attributes and attach it to the containing feature.  */

static void

tdesc_start_reg (struct gdb_xml_parser *parser,

                 const struct gdb_xml_element *element,

                 void *user_data, VEC(gdb_xml_value_s) *attributes)

{

  struct tdesc_parsing_data *data = user_data;

  struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);

  int ix = 0, length;

  char *name, *group, *type;

  int bitsize, regnum, save_restore;

  length = VEC_length (gdb_xml_value_s, attributes);

  name = attrs[ix++].value;

  bitsize = * (ULONGEST *) attrs[ix++].value;

  if (ix < length && strcmp (attrs[ix].name, "regnum") == 0)

    regnum = * (ULONGEST *) attrs[ix++].value;

  else

    regnum = data->next_regnum;

  if (ix < length && strcmp (attrs[ix].name, "type") == 0)

    type = attrs[ix++].value;

  else

    type = "int";

  if (ix < length && strcmp (attrs[ix].name, "group") == 0)

    group = attrs[ix++].value;

  else

    group = NULL;

  if (ix < length && strcmp (attrs[ix].name, "save-restore") == 0)

    save_restore = * (ULONGEST *) attrs[ix++].value;

  else

    save_restore = 1;

  if (strcmp (type, "int") != 0

      && strcmp (type, "float") != 0

      && tdesc_named_type (data->current_feature, type) == NULL)

    gdb_xml_error (parser, _("Register \"%s\" has unknown type \"%s\""),

                   name, type);

  tdesc_create_reg (data->current_feature, name, regnum, save_restore, group,

                    bitsize, type);

  data->next_regnum = regnum + 1;

}

/* Handle the start of a <union> element.  Initialize the type and

   record it with the current feature.  */

static void

tdesc_start_union (struct gdb_xml_parser *parser,

                   const struct gdb_xml_element *element,

                   void *user_data, VEC(gdb_xml_value_s) *attributes)

{

  struct tdesc_parsing_data *data = user_data;

  char *id = VEC_index (gdb_xml_value_s, attributes, 0)->value;

  data->current_type = tdesc_create_union (data->current_feature, id);

  data->current_type_size = 0;

  data->current_type_is_flags = 0;

}

/* Handle the start of a <struct> element.  Initialize the type and

   record it with the current feature.  */

static void

tdesc_start_struct (struct gdb_xml_parser *parser,

                   const struct gdb_xml_element *element,

                   void *user_data, VEC(gdb_xml_value_s) *attributes)

{

  struct tdesc_parsing_data *data = user_data;

  char *id = VEC_index (gdb_xml_value_s, attributes, 0)->value;

  struct tdesc_type *type;

  type = tdesc_create_struct (data->current_feature, id);

  data->current_type = type;

  data->current_type_size = 0;

  data->current_type_is_flags = 0;

  if (VEC_length (gdb_xml_value_s, attributes) > 1)

    {

      int size = (int) * (ULONGEST *)

        VEC_index (gdb_xml_value_s, attributes, 1)->value;

      tdesc_set_struct_size (type, size);

      data->current_type_size = size;

    }

}

static void

tdesc_start_flags (struct gdb_xml_parser *parser,

                   const struct gdb_xml_element *element,

                   void *user_data, VEC(gdb_xml_value_s) *attributes)

{

  struct tdesc_parsing_data *data = user_data;

  char *id = VEC_index (gdb_xml_value_s, attributes, 0)->value;

  int length = (int) * (ULONGEST *)

    VEC_index (gdb_xml_value_s, attributes, 1)->value;

  struct tdesc_type *type;

  type = tdesc_create_flags (data->current_feature, id, length);

  data->current_type = type;

  data->current_type_size = 0;

  data->current_type_is_flags = 1;

}

/* Handle the start of a <field> element.  Attach the field to the

   current struct or union.  */

static void

tdesc_start_field (struct gdb_xml_parser *parser,

                   const struct gdb_xml_element *element,

                   void *user_data, VEC(gdb_xml_value_s) *attributes)

{

  struct tdesc_parsing_data *data = user_data;

  int ix = 0, length;

  struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);

  struct tdesc_type *field_type;

  char *field_name, *field_type_id;

  int start, end;

  length = VEC_length (gdb_xml_value_s, attributes);

  field_name = attrs[ix++].value;

  if (ix < length && strcmp (attrs[ix].name, "type") == 0)

    field_type_id = attrs[ix++].value;

  else

    field_type_id = NULL;

  if (ix < length && strcmp (attrs[ix].name, "start") == 0)

    start = * (ULONGEST *) attrs[ix++].value;

  else

    start = -1;

  if (ix < length && strcmp (attrs[ix].name, "end") == 0)

    end = * (ULONGEST *) attrs[ix++].value;

  else

    end = -1;

  if (field_type_id != NULL)

    {

      if (data->current_type_is_flags)

        gdb_xml_error (parser, _("Cannot add typed field \"%s\" to flags"),

                       field_name);

      if (data->current_type_size != 0)

        gdb_xml_error (parser,

                       _("Explicitly sized type can not contain non-bitfield \"%s\""),

                       field_name);

      field_type = tdesc_named_type (data->current_feature, field_type_id);

      if (field_type == NULL)

        gdb_xml_error (parser, _("Field \"%s\" references undefined "

                                 "type \"%s\""),

                       field_name, field_type_id);

      tdesc_add_field (data->current_type, field_name, field_type);

    }

  else if (start != -1 && end != -1)

    {

      struct tdesc_type *t = data->current_type;

      if (data->current_type_is_flags)

        tdesc_add_flag (t, start, field_name);

      else

        {

          if (data->current_type_size == 0)

            gdb_xml_error (parser,

                           _("Implicitly sized type can not contain bitfield \"%s\""),

                           field_name);

          if (end >= 64)

            gdb_xml_error (parser,

                           _("Bitfield \"%s\" goes past 64 bits (unsupported)"),

                           field_name);

          /* Assume that the bit numbering in XML is "lsb-zero".  Most

             architectures other than PowerPC use this ordering.  In

             the future, we can add an XML tag to indicate "msb-zero"

             numbering.  */

          if (start > end)

            gdb_xml_error (parser, _("Bitfield \"%s\" has start after end"),

                           field_name);

          if (end >= data->current_type_size * TARGET_CHAR_BIT)

            gdb_xml_error (parser, _("Bitfield \"%s\" does not fit in struct"));

          tdesc_add_bitfield (t, field_name, start, end);

        }

    }

  else

    gdb_xml_error (parser, _("Field \"%s\" has neither type nor bit position"),

                   field_name);

}

/* Handle the start of a <vector> element.  Initialize the type and

   record it with the current feature.  */

static void

tdesc_start_vector (struct gdb_xml_parser *parser,

                    const struct gdb_xml_element *element,

                    void *user_data, VEC(gdb_xml_value_s) *attributes)

{

  struct tdesc_parsing_data *data = user_data;

  struct gdb_xml_value *attrs = VEC_address (gdb_xml_value_s, attributes);

  struct tdesc_type *field_type;

  char *id, *field_type_id;

  int count;

  id = attrs[0].value;

  field_type_id = attrs[1].value;

  count = * (ULONGEST *) attrs[2].value;

  field_type = tdesc_named_type (data->current_feature, field_type_id);

  if (field_type == NULL)

    gdb_xml_error (parser, _("Vector \"%s\" references undefined type \"%s\""),

                   id, field_type_id);

  tdesc_create_vector (data->current_feature, id, field_type, count);

}

/* The elements and attributes of an XML target description.  */

static const struct gdb_xml_attribute field_attributes[] = {

  { "name", GDB_XML_AF_NONE, NULL, NULL },

  { "type", GDB_XML_AF_OPTIONAL, NULL, NULL },

  { "start", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },

  { "end", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },

  { NULL, GDB_XML_AF_NONE, NULL, NULL }

};

static const struct gdb_xml_element struct_union_children[] = {

  { "field", field_attributes, NULL, GDB_XML_EF_REPEATABLE,

    tdesc_start_field, NULL },

  { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }

};

static const struct gdb_xml_attribute reg_attributes[] = {

  { "name", GDB_XML_AF_NONE, NULL, NULL },

  { "bitsize", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },

  { "regnum", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL },

  { "type", GDB_XML_AF_OPTIONAL, NULL, NULL },

  { "group", GDB_XML_AF_OPTIONAL, NULL, NULL },

  { "save-restore", GDB_XML_AF_OPTIONAL,

    gdb_xml_parse_attr_enum, gdb_xml_enums_boolean },

  { NULL, GDB_XML_AF_NONE, NULL, NULL }

};

static const struct gdb_xml_attribute struct_union_attributes[] = {

  { "id", GDB_XML_AF_NONE, NULL, NULL },

  { "size", GDB_XML_AF_OPTIONAL, gdb_xml_parse_attr_ulongest, NULL},

  { NULL, GDB_XML_AF_NONE, NULL, NULL }

};

static const struct gdb_xml_attribute flags_attributes[] = {

  { "id", GDB_XML_AF_NONE, NULL, NULL },

  { "size", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL},

  { NULL, GDB_XML_AF_NONE, NULL, NULL }

};

static const struct gdb_xml_attribute vector_attributes[] = {

  { "id", GDB_XML_AF_NONE, NULL, NULL },

  { "type", GDB_XML_AF_NONE, NULL, NULL },

  { "count", GDB_XML_AF_NONE, gdb_xml_parse_attr_ulongest, NULL },

  { NULL, GDB_XML_AF_NONE, NULL, NULL }

};

static const struct gdb_xml_attribute feature_attributes[] = {

  { "name", GDB_XML_AF_NONE, NULL, NULL },

  { NULL, GDB_XML_AF_NONE, NULL, NULL }

};

static const struct gdb_xml_element feature_children[] = {

  { "reg", reg_attributes, NULL,

    GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,

    tdesc_start_reg, NULL },

  { "struct", struct_union_attributes, struct_union_children,

    GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,

    tdesc_start_struct, NULL },

  { "union", struct_union_attributes, struct_union_children,

    GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,

    tdesc_start_union, NULL },

  { "flags", flags_attributes, struct_union_children,

    GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,

    tdesc_start_flags, NULL },

  { "vector", vector_attributes, NULL,

    GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,

    tdesc_start_vector, NULL },

  { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }

};

static const struct gdb_xml_attribute target_attributes[] = {

  { "version", GDB_XML_AF_NONE, NULL, NULL },

  { NULL, GDB_XML_AF_NONE, NULL, NULL }

};

static const struct gdb_xml_element target_children[] = {

  { "architecture", NULL, NULL, GDB_XML_EF_OPTIONAL,

    NULL, tdesc_end_arch },

  { "osabi", NULL, NULL, GDB_XML_EF_OPTIONAL,

    NULL, tdesc_end_osabi },

  { "compatible", NULL, NULL, GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,

    NULL, tdesc_end_compatible },

  { "feature", feature_attributes, feature_children,

    GDB_XML_EF_OPTIONAL | GDB_XML_EF_REPEATABLE,

    tdesc_start_feature, NULL },

  { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }

};

static const struct gdb_xml_element tdesc_elements[] = {

  { "target", target_attributes, target_children, GDB_XML_EF_NONE,

    tdesc_start_target, NULL },

  { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }

};

/* Parse DOCUMENT into a target description and return it.  */

static struct target_desc *

tdesc_parse_xml (const char *document, xml_fetch_another fetcher,

                 void *fetcher_baton)

{

  struct cleanup *back_to, *result_cleanup;

  struct gdb_xml_parser *parser;

  struct tdesc_parsing_data data;

  struct tdesc_xml_cache *cache;

  char *expanded_text;

  int ix;

  /* Expand all XInclude directives.  */

  expanded_text = xml_process_xincludes (_("target description"),

                                         document, fetcher, fetcher_baton, 0);

  if (expanded_text == NULL)

    {

      warning (_("Could not load XML target description; ignoring"));

      return NULL;

    }

  /* Check for an exact match in the list of descriptions we have

     previously parsed.  strcmp is a slightly inefficient way to

     do this; an SHA-1 checksum would work as well.  */

  for (ix = 0; VEC_iterate (tdesc_xml_cache_s, xml_cache, ix, cache); ix++)

    if (strcmp (cache->xml_document, expanded_text) == 0)

      {

       xfree (expanded_text);

       return cache->tdesc;

      }

  back_to = make_cleanup (null_cleanup, NULL);

  parser = gdb_xml_create_parser_and_cleanup (_("target description"),

                                              tdesc_elements, &data);

  gdb_xml_use_dtd (parser, "gdb-target.dtd");

  memset (&data, 0, sizeof (struct tdesc_parsing_data));

  data.tdesc = allocate_target_description ();

  result_cleanup = make_cleanup_free_target_description (data.tdesc);

  make_cleanup (xfree, expanded_text);

  if (gdb_xml_parse (parser, expanded_text) == 0)

    {

      /* Parsed successfully.  */

      struct tdesc_xml_cache new_cache;

      new_cache.xml_document = expanded_text;

      new_cache.tdesc = data.tdesc;

      VEC_safe_push (tdesc_xml_cache_s, xml_cache, &new_cache);

      discard_cleanups (result_cleanup);

      do_cleanups (back_to);

      return data.tdesc;

    }

  else

    {

      warning (_("Could not load XML target description; ignoring"));

      do_cleanups (back_to);

      return NULL;

    }

}

#endif /* HAVE_LIBEXPAT */

/* Read an XML target description from FILENAME.  Parse it, and return

   the parsed description.  */

const struct target_desc *

file_read_description_xml (const char *filename)

{

  struct target_desc *tdesc;

  char *tdesc_str;

  struct cleanup *back_to;

  char *dirname;

  tdesc_str = xml_fetch_content_from_file (filename, NULL);

  if (tdesc_str == NULL)

    {

      warning (_("Could not open \"%s\""), filename);

      return NULL;

    }

  back_to = make_cleanup (xfree, tdesc_str);

  dirname = ldirname (filename);

  if (dirname != NULL)

    make_cleanup (xfree, dirname);

  tdesc = tdesc_parse_xml (tdesc_str, xml_fetch_content_from_file, dirname);

  do_cleanups (back_to);

  return tdesc;

}

/* Read a string representation of available features from the target,

   using TARGET_OBJECT_AVAILABLE_FEATURES.  The returned string is

   malloc allocated and NUL-terminated.  NAME should be a non-NULL

   string identifying the XML document we want; the top level document

   is "target.xml".  Other calls may be performed for the DTD or

   for <xi:include>.  */

static char *

fetch_available_features_from_target (const char *name, void *baton_)

{

  struct target_ops *ops = baton_;

  /* Read this object as a string.  This ensures that a NUL

     terminator is added.  */

  return target_read_stralloc (ops,

                               TARGET_OBJECT_AVAILABLE_FEATURES,

                               name);

}

/* Read an XML target description using OPS.  Parse it, and return the

   parsed description.  */

const struct target_desc *

target_read_description_xml (struct target_ops *ops)

{

  struct target_desc *tdesc;

  char *tdesc_str;

  struct cleanup *back_to;

  tdesc_str = fetch_available_features_from_target ("target.xml", ops);

  if (tdesc_str == NULL)

    return NULL;

  back_to = make_cleanup (xfree, tdesc_str);

  tdesc = tdesc_parse_xml (tdesc_str,

                           fetch_available_features_from_target,

                           ops);

  do_cleanups (back_to);

  return tdesc;

}