Move gdbserver to top level

This patch moves gdbserver to the top level.

This patch is as close to a pure move as possible -- gdbserver still
builds its own variant of gnulib and gdbsupport.  Changing this will
be done in a separate patch.

[v2] Note that, per Simon's review comment, this patch changes the
tree so that gdbserver is not built for or1k or score.  This makes
sense, because there is apparently not actually a gdbserver port here.

[v3] This version of the patch also splits out some configury into a
new file, gdbserver/configure.host, so that the top-level configure
script can simply rely on it in order to decide whether gdbserver
should be built.

[v4] This version adds documentation and removes some unnecessary
top-level dependencies.

[v5] Update docs to mention "make all-gdbserver" and change how
top-level configure decides whether to build gdbserver, switching to a
single, shared script.

Tested by the buildbot.

ChangeLog
2020-02-07  Tom Tromey  <tom@tromey.com>
	    Pedro Alves  <palves@redhat.com>

	* src-release.sh (GDB_SUPPORT_DIRS): Add gdbserver.
	* gdbserver: New directory, moved from gdb/gdbserver.
	* configure.ac (host_tools): Add gdbserver.
	Only build gdbserver on certain systems.
	* Makefile.in, configure: Rebuild.
	* Makefile.def (host_modules, dependencies): Add gdbserver.
	* MAINTAINERS: Add gdbserver.

gdb/ChangeLog
2020-02-07  Tom Tromey  <tom@tromey.com>

	* README: Update gdbserver documentation.
	* gdbserver: Move to top level.
	* configure.tgt (build_gdbserver): Remove.
	* configure.ac: Remove --enable-gdbserver.
	* configure: Rebuild.
	* Makefile.in (distclean): Don't mention gdbserver.

Change-Id: I826b7565b54604711dc7a11edea0499cd51ff39e

1 files changed, 101 insertions, 0 deletions

diff --git a/gdbserver/tdesc.h b/gdbserver/tdesc.h
new file mode 100644
index 0000000..5e0df85
--- /dev/null
+++ b/gdbserver/tdesc.h
@@ -0,0 +1,101 @@
+/* Target description definitions for remote server for GDB.
+   Copyright (C) 2012-2020 Free Software Foundation, Inc.
+
+   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/>.  */
+
+#ifndef GDBSERVER_TDESC_H
+#define GDBSERVER_TDESC_H
+
+#include "gdbsupport/tdesc.h"
+
+#include "regdef.h"
+#include <vector>
+
+/* A target description.  Inherit from tdesc_feature so that target_desc
+   can be used as tdesc_feature.  */
+
+struct target_desc : tdesc_element
+{
+  /* A vector of elements of register definitions that
+     describe the inferior's register set.  */
+  std::vector<struct reg> reg_defs;
+
+  /* The register cache size, in bytes.  */
+  int registers_size;
+
+  /* XML features in this target description.  */
+  std::vector<tdesc_feature_up> features;
+
+#ifndef IN_PROCESS_AGENT
+  /* An array of register names.  These are the "expedite" registers:
+     registers whose values are sent along with stop replies.  */
+  const char **expedite_regs = NULL;
+
+  /* Defines what to return when looking for the "target.xml" file in
+     response to qXfer:features:read.  Its contents can either be
+     verbatim XML code (prefixed with a '@') or else the name of the
+     actual XML file to be used in place of "target.xml".
+
+     If NULL then its content will be generated by parsing the target
+     description into xml.  */
+  mutable const char *xmltarget = NULL;
+
+  /* The value of <architecture> element in the XML, replying GDB.  */
+  const char *arch = NULL;
+
+  /* The value of <osabi> element in the XML, replying GDB.  */
+  const char *osabi = NULL;
+
+public:
+  target_desc ()
+    : registers_size (0)
+  {}
+
+  ~target_desc ();
+
+  bool operator== (const target_desc &other) const;
+
+  bool operator!= (const target_desc &other) const
+  {
+    return !(*this == other);
+  }
+#endif
+
+  void accept (tdesc_element_visitor &v) const override;
+};
+
+/* Copy target description SRC to DEST.  */
+
+void copy_target_description (struct target_desc *dest,
+			      const struct target_desc *src);
+
+/* Initialize TDESC, and then set its expedite_regs field to
+   EXPEDITE_REGS.  */
+
+void init_target_desc (struct target_desc *tdesc,
+		       const char **expedite_regs);
+
+/* Return the current inferior's target description.  Never returns
+   NULL.  */
+
+const struct target_desc *current_target_desc (void);
+
+/* Return true if TDESC contains the feature described by string FEATURE.
+   Return false otherwise.  */
+bool tdesc_contains_feature (const target_desc *tdesc,
+			     const std::string &feature);
+
+#endif /* GDBSERVER_TDESC_H */