Move gdbsupport to the top level

This patch moves the gdbsupport directory to the top level.  This is
the next step in the ongoing project to move gdbserver to the top
level.

The bulk of this patch was created by "git mv gdb/gdbsupport gdbsupport".

This patch then adds a build system to gdbsupport and wires it into
the top level.  Then it changes gdb to use the top-level build.

gdbserver, on the other hand, is not yet changed.  It still does its
own build of gdbsupport.

ChangeLog
2020-01-14  Tom Tromey  <tom@tromey.com>

	* src-release.sh (GDB_SUPPORT_DIRS): Add gdbsupport.
	* MAINTAINERS: Add gdbsupport.
	* configure: Rebuild.
	* configure.ac (configdirs): Add gdbsupport.
	* gdbsupport: New directory, move from gdb/gdbsupport.
	* Makefile.def (host_modules, dependencies): Add gnulib.
	* Makefile.in: Rebuild.

gdb/ChangeLog
2020-01-14  Tom Tromey  <tom@tromey.com>

	* nat/x86-linux-dregs.c: Include configh.h.
	* nat/linux-ptrace.c: Include configh.h.
	* nat/linux-btrace.c: Include configh.h.
	* defs.h: Include config.h, bfd.h.
	* configure.ac: Don't source common.host.
	(CONFIG_OBS, CONFIG_SRCS): Remove gdbsupport files.
	* configure: Rebuild.
	* acinclude.m4: Update path.
	* Makefile.in (SUPPORT, LIBSUPPORT, INCSUPPORT): New variables.
	(CONFIG_SRC_SUBDIR): Remove gdbsupport.
	(INTERNAL_CFLAGS_BASE): Add INCSUPPORT.
	(CLIBS): Add LIBSUPPORT.
	(CDEPS): Likewise.
	(COMMON_SFILES): Remove gdbsupport files.
	(HFILES_NO_SRCDIR): Likewise.
	(stamp-version): Update path to create-version.sh.
	(ALLDEPFILES): Remove gdbsupport files.

gdb/gdbserver/ChangeLog
2020-01-14  Tom Tromey  <tom@tromey.com>

	* server.h: Include config.h.
	* gdbreplay.c: Include config.h.
	* configure: Rebuild.
	* configure.ac: Don't source common.host.
	* acinclude.m4: Update path.
	* Makefile.in (INCSUPPORT): New variable.
	(INCLUDE_CFLAGS): Add INCSUPPORT.
	(SFILES): Update paths.
	(version-generated.c): Update path to create-version.sh.
	(gdbsupport/%-ipa.o, gdbsupport/%.o): Update paths.

gdbsupport/ChangeLog
2020-01-14  Tom Tromey  <tom@tromey.com>

	* common-defs.h: Add GDBSERVER case.  Update includes.
	* acinclude.m4, aclocal.m4, config.in, configure, configure.ac,
	Makefile.am, Makefile.in, README: New files.
	* Moved from ../gdb/gdbsupport/

Change-Id: I07632e7798635c1bab389bf885971e584fb4bb78

1 files changed, 119 insertions, 0 deletions

diff --git a/gdbsupport/observable.h b/gdbsupport/observable.h
new file mode 100644
index 00000000000..0468ebabcf6
--- /dev/null
+++ b/gdbsupport/observable.h
@@ -0,0 +1,119 @@
+/* Observers
+
+   Copyright (C) 2016-2020 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 COMMON_OBSERVABLE_H
+#define COMMON_OBSERVABLE_H
+
+#include <algorithm>
+#include <functional>
+#include <vector>
+
+namespace gdb
+{
+
+namespace observers
+{
+
+extern unsigned int observer_debug;
+
+/* An observer is an entity which is interested in being notified
+   when GDB reaches certain states, or certain events occur in GDB.
+   The entity being observed is called the observable.  To receive
+   notifications, the observer attaches a callback to the observable.
+   One observable can have several observers.
+
+   The observer implementation is also currently not reentrant.  In
+   particular, it is therefore not possible to call the attach or
+   detach routines during a notification.  */
+
+/* The type of a key that can be passed to attach, which can be passed
+   to detach to remove associated observers.  Tokens have address
+   identity, and are thus usually const globals.  */
+struct token
+{
+  token () = default;
+
+  DISABLE_COPY_AND_ASSIGN (token);
+};
+
+template<typename... T>
+class observable
+{
+public:
+
+  typedef std::function<void (T...)> func_type;
+
+  explicit observable (const char *name)
+    : m_name (name)
+  {
+  }
+
+  DISABLE_COPY_AND_ASSIGN (observable);
+
+  /* Attach F as an observer to this observable.  F cannot be
+     detached.  */
+  void attach (const func_type &f)
+  {
+    m_observers.emplace_back (nullptr, f);
+  }
+
+  /* Attach F as an observer to this observable.  T is a reference to
+     a token that can be used to later remove F.  */
+  void attach (const func_type &f, const token &t)
+  {
+    m_observers.emplace_back (&t, f);
+  }
+
+  /* Remove observers associated with T from this observable.  T is
+     the token that was previously passed to any number of "attach"
+     calls.  */
+  void detach (const token &t)
+  {
+    auto iter = std::remove_if (m_observers.begin (),
+				m_observers.end (),
+				[&] (const std::pair<const token *,
+				     func_type> &e)
+				{
+				  return e.first == &t;
+				});
+
+    m_observers.erase (iter, m_observers.end ());
+  }
+
+  /* Notify all observers that are attached to this observable.  */
+  void notify (T... args) const
+  {
+    if (observer_debug)
+      fprintf_unfiltered (gdb_stdlog, "observable %s notify() called\n",
+			  m_name);
+    for (auto &&e : m_observers)
+      e.second (args...);
+  }
+
+private:
+
+  std::vector<std::pair<const token *, func_type>> m_observers;
+  const char *m_name;
+};
+
+} /* namespace observers */
+
+} /* namespace gdb */
+
+#endif /* COMMON_OBSERVABLE_H */