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, 109 insertions, 0 deletions

diff --git a/gdbserver/nto-x86-low.c b/gdbserver/nto-x86-low.c
new file mode 100644
index 0000000..efee957
--- /dev/null
+++ b/gdbserver/nto-x86-low.c
@@ -0,0 +1,109 @@
+/* QNX Neutrino specific low level interface, for the remote server
+   for GDB.
+   Copyright (C) 2009-2020 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/>.  */
+
+#include "server.h"
+#include "nto-low.h"
+#include "regdef.h"
+#include "regcache.h"
+
+#include <x86/context.h>
+#include "gdbsupport/x86-xstate.h"
+#include "arch/i386.h"
+#include "x86-tdesc.h"
+
+const unsigned char x86_breakpoint[] = { 0xCC };
+#define x86_breakpoint_len 1
+
+/* Returns offset in appropriate Neutrino's context structure.
+   Defined in x86/context.h.
+   GDBREGNO is index into regs_i386 array.  It is autogenerated and
+   hopefully doesn't change.  */
+static int
+nto_x86_register_offset (int gdbregno)
+{
+  if (gdbregno >= 0 && gdbregno < 16)
+    {
+      X86_CPU_REGISTERS *dummy = (void*)0;
+      /* GPRs  */
+      switch (gdbregno)
+	{
+	case 0: 
+	  return (int)&(dummy->eax);
+	case 1:
+	  return (int)&(dummy->ecx);
+	case 2:
+	  return (int)&(dummy->edx);
+	case 3:
+	  return (int)&(dummy->ebx);
+	case 4:
+	  return (int)&(dummy->esp);
+	case 5:
+	  return (int)&(dummy->ebp);
+	case 6:
+	  return (int)&(dummy->esi);
+	case 7:
+	  return (int)&(dummy->edi);
+	case 8:
+	  return (int)&(dummy->eip);
+	case 9:
+	  return (int)&(dummy->efl);
+	case 10:
+	  return (int)&(dummy->cs);
+	case 11:
+	  return (int)&(dummy->ss);
+#ifdef __SEGMENTS__
+	case 12:
+	  return (int)&(dummy->ds);
+	case 13:
+	  return (int)&(dummy->es);
+	case 14:
+	  return (int)&(dummy->fs);
+	case 15:
+	  return (int)&(dummy->gs);
+#endif
+	default:
+	  return -1;
+	}
+    }
+  return -1;
+}
+
+static void
+nto_x86_arch_setup (void)
+{
+  the_low_target.num_regs = 16;
+  struct target_desc *tdesc
+    = i386_create_target_description (X86_XSTATE_SSE_MASK, false, false);
+
+  init_target_desc (tdesc, i386_expedite_regs);
+
+  nto_tdesc = tdesc;
+}
+
+struct nto_target_ops the_low_target =
+{
+  nto_x86_arch_setup,
+  0, /* num_regs */
+  nto_x86_register_offset,
+  x86_breakpoint,
+  x86_breakpoint_len
+};
+
+
+