XML feature description support.

	* NEWS: Mention target descriptions, "set tdesc filename",
	"unset tdesc filename", "show tdesc filename", and
	qXfer:features:read.
	* arch-utils.c (choose_architecture_for_target): New function.
	(gdbarch_info_fill): Call it.
	* target-descriptions.c (struct property): Make members non-const.
	(struct target_desc): Add arch member.
	(target_description_filename): New variable.
	(target_find_description): Try via XML first.
	(tdesc_architecture): New.
	(free_target_description, make_cleanup_free_target_description): New.
	(set_tdesc_property): Call xstrdup.
	(set_tdesc_architecture, tdesc_set_cmdlist, tdesc_show_cmdlist)
	(tdesc_unset_cmdlist, unset_tdesc_cmd, unset_tdesc_filename_cmd)
	(set_tdesc_cmd, show_tdesc_cmd, set_tdesc_filename_cmd)
	(show_tdesc_filename_cmd, _initialize_target_descriptions): New.
	* target-descriptions.h (tdesc_architecture)
	(make_cleanup_free_target_description, set_tdesc_architecture): New
	prototypes.
	* Makefile.in (SFILES): Add xml-tdesc.c.
	(COMMON_OBS): Add xml-tdesc.o.
	(target-descriptions.o): Update.
	(xml-tdesc.o): New rule.
	* xml-tdesc.c, xml-tdesc.h: New files.
	* remote.c (PACKET_qXfer_features): New enum.
	(remote_protocol_features): Add qXfer:features:read.
	(remote_xfer_partial): Handle TARGET_OBJECT_AVAILABLE_FEATURES.
	(_initialize_remote): Register qXfer:features:read.
	* target.h (enum target_object): Add TARGET_OBJECT_AVAILABLE_FEATURES.
	* features/gdb-target.dtd: New file.

	* linux-i386-low.c (the_low_target): Set arch_string.
	* linux-x86-64-low.c (the_low_target): Likewise.
	* linux-low.c (linux_arch_string): New.
	(linux_target_ops): Add it.
	* linux-low.h (struct linux_target_ops): Add arch_string.
	* server.c (write_qxfer_response): Use const void * for DATA.
	(get_features_xml): New.
	(handle_query): Handle qXfer:features:read.  Report it for qSupported.
	* target.h (struct target_ops): Add arch_string method.

	* gdb.texinfo (Target Descriptions): New section.
	(General Query Packets): Add QPassSignals anchor.  Mention
	qXfer:features:read under qSupported.  Expand mentions of
	qXfer:memory-map:read and QPassSignals.  Document
	qXfer:features:read.

1 files changed, 233 insertions, 0 deletions

diff --git a/gdb/xml-tdesc.c b/gdb/xml-tdesc.c
new file mode 100644
index 00000000000..f47e3687b81
--- /dev/null
+++ b/gdb/xml-tdesc.c
@@ -0,0 +1,233 @@
+/* XML target description support for GDB.
+
+   Copyright (C) 2006
+   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 2 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, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor,
+   Boston, MA 02110-1301, USA.  */
+
+#include "defs.h"
+#include "target.h"
+#include "target-descriptions.h"
+#include "xml-support.h"
+#include "xml-tdesc.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)
+{
+  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 */
+
+/* Callback data for target description parsing.  */
+
+struct tdesc_parsing_data
+{
+  /* The target description we are building.  */
+  struct target_desc *tdesc;
+};
+
+/* 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);
+}
+
+/* The elements and attributes of an XML target description.  */
+
+const struct gdb_xml_element target_children[] = {
+  { "architecture", NULL, NULL, GDB_XML_EF_OPTIONAL,
+    NULL, tdesc_end_arch },
+  { NULL, NULL, NULL, GDB_XML_EF_NONE, NULL, NULL }
+};
+
+const struct gdb_xml_element tdesc_elements[] = {
+  { "target", NULL, target_children, GDB_XML_EF_NONE,
+    NULL, 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)
+{
+  struct cleanup *back_to, *result_cleanup;
+  struct gdb_xml_parser *parser;
+  struct tdesc_parsing_data data;
+
+  memset (&data, 0, sizeof (struct tdesc_parsing_data));
+
+  back_to = make_cleanup (null_cleanup, NULL);
+  parser = gdb_xml_create_parser_and_cleanup (_("target description"),
+					      tdesc_elements, &data);
+
+  data.tdesc = allocate_target_description ();
+  result_cleanup = make_cleanup_free_target_description (data.tdesc);
+
+  if (gdb_xml_parse (parser, document) == 0)
+    {
+      /* Parsed successfully.  */
+      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 */
+
+
+/* Close FILE.  */
+
+static void
+do_cleanup_fclose (void *file)
+{
+  fclose (file);
+}
+
+/* Open FILENAME, read all its text into memory, close it, and return
+   the text.  If something goes wrong, return NULL and warn.  */
+
+static char *
+fetch_xml_from_file (const char *filename)
+{
+  FILE *file;
+  struct cleanup *back_to;
+  char *text;
+  size_t len, offset;
+
+  file = fopen (filename, FOPEN_RT);
+  if (file == NULL)
+    {
+      warning (_("Could not open \"%s\""), filename);
+      return NULL;
+    }
+  back_to = make_cleanup (do_cleanup_fclose, file);
+
+  /* Read in the whole file, one chunk at a time.  */
+  len = 4096;
+  offset = 0;
+  text = xmalloc (len);
+  make_cleanup (free_current_contents, &text);
+  while (1)
+    {
+      size_t bytes_read;
+
+      /* Continue reading where the last read left off.  Leave at least
+	 one byte so that we can NUL-terminate the result.  */
+      bytes_read = fread (text + offset, 1, len - offset - 1, file);
+      if (ferror (file))
+	{
+	  warning (_("Read error from \"%s\""), filename);
+	  do_cleanups (back_to);
+	  return NULL;
+	}
+
+      offset += bytes_read;
+
+      if (feof (file))
+	break;
+
+      len = len * 2;
+      text = xrealloc (text, len);
+    }
+
+  fclose (file);
+  discard_cleanups (back_to);
+
+  text[offset] = '\0';
+  return text;
+}
+
+/* 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;
+
+  tdesc_str = fetch_xml_from_file (filename);
+  if (tdesc_str == NULL)
+    return NULL;
+
+  back_to = make_cleanup (xfree, tdesc_str);
+  tdesc = tdesc_parse_xml (tdesc_str);
+  do_cleanups (back_to);
+
+  return tdesc;
+}
+
+/* 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 = target_read_stralloc (ops, TARGET_OBJECT_AVAILABLE_FEATURES,
+				    "target.xml");
+  if (tdesc_str == NULL)
+    return NULL;
+
+  back_to = make_cleanup (xfree, tdesc_str);
+  tdesc = tdesc_parse_xml (tdesc_str);
+  do_cleanups (back_to);
+
+  return tdesc;
+}