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, 133 insertions, 0 deletions

diff --git a/gdbsupport/offset-type.h b/gdbsupport/offset-type.h
new file mode 100644
index 0000000..b68cb45
--- /dev/null
+++ b/gdbsupport/offset-type.h
@@ -0,0 +1,133 @@
+/* Offset types for GDB.
+
+   Copyright (C) 2017-2020 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/>.  */
+
+/* Define an "offset" type.  Offset types are distinct integer types
+   that are used to represent an offset into anything that is
+   addressable.  For example, an offset into a DWARF debug section.
+   The idea is catch mixing unrelated offset types at compile time, in
+   code that needs to manipulate multiple different kinds of offsets
+   that are easily confused.  They're safer to use than native
+   integers, because they have no implicit conversion to anything.
+   And also, since they're implemented as "enum class" strong
+   typedefs, they're still integers ABI-wise, making them a bit more
+   efficient than wrapper structs on some ABIs.
+
+   Some properties of offset types, loosely modeled on pointers:
+
+   - You can compare offsets of the same type for equality and order.
+     You can't compare an offset with an unrelated type.
+
+   - You can add/substract an integer to/from an offset, which gives
+     you back a shifted offset.
+
+   - You can subtract two offsets of the same type, which gives you
+     back the delta as an integer (of the enum class's underlying
+     type), not as an offset type.
+
+   - You can't add two offsets of the same type, as that would not
+     make sense.
+
+   However, unlike pointers, you can't deference offset types.  */
+
+#ifndef COMMON_OFFSET_TYPE_H
+#define COMMON_OFFSET_TYPE_H
+
+/* Declare TYPE as being an offset type.  This declares the type and
+   enables the operators defined below.  */
+#define DEFINE_OFFSET_TYPE(TYPE, UNDERLYING)	\
+  enum class TYPE : UNDERLYING {};		\
+  void is_offset_type (TYPE)
+
+/* The macro macro is all you need to know use offset types.  The rest
+   below is all implementation detail.  */
+
+/* For each enum class type that you want to support arithmetic
+   operators, declare an "is_offset_type" overload that has exactly
+   one parameter, of type that enum class.  E.g.,:
+
+     void is_offset_type (sect_offset);
+
+   The function does not need to be defined, only declared.
+   DEFINE_OFFSET_TYPE declares this.
+
+   A function declaration is preferred over a traits type, because the
+   former allows calling the DEFINE_OFFSET_TYPE macro inside a
+   namespace to define the corresponding offset type in that
+   namespace.  The compiler finds the corresponding is_offset_type
+   function via ADL.
+*/
+
+/* Adding or subtracting an integer to an offset type shifts the
+   offset.  This is like "PTR = PTR + INT" and "PTR += INT".  */
+
+#define DEFINE_OFFSET_ARITHM_OP(OP)					\
+  template<typename E,							\
+	   typename = decltype (is_offset_type (std::declval<E> ()))>	\
+  constexpr E								\
+  operator OP (E lhs, typename std::underlying_type<E>::type rhs)	\
+  {									\
+    using underlying = typename std::underlying_type<E>::type;		\
+    return (E) (static_cast<underlying> (lhs) OP rhs);			\
+  }									\
+									\
+  template<typename E,							\
+	   typename = decltype (is_offset_type (std::declval<E> ()))>	\
+  constexpr E								\
+  operator OP (typename std::underlying_type<E>::type lhs, E rhs)	\
+  {									\
+    using underlying = typename std::underlying_type<E>::type;		\
+    return (E) (lhs OP static_cast<underlying> (rhs));			\
+  }									\
+									\
+  template<typename E,							\
+	   typename = decltype (is_offset_type (std::declval<E> ()))>	\
+  E &									\
+  operator OP ## = (E &lhs, typename std::underlying_type<E>::type rhs)	\
+  {									\
+    using underlying = typename std::underlying_type<E>::type;		\
+    lhs = (E) (static_cast<underlying> (lhs) OP rhs);			\
+    return lhs;								\
+  }
+
+DEFINE_OFFSET_ARITHM_OP(+)
+DEFINE_OFFSET_ARITHM_OP(-)
+
+/* Adding two offset types doesn't make sense, just like "PTR + PTR"
+   doesn't make sense.  This is defined as a deleted function so that
+   a compile error easily brings you to this comment.  */
+
+template<typename E,
+	 typename = decltype (is_offset_type (std::declval<E> ()))>
+constexpr typename std::underlying_type<E>::type
+operator+ (E lhs, E rhs) = delete;
+
+/* Subtracting two offset types, however, gives you back the
+   difference between the offsets, as an underlying type.  Similar to
+   how "PTR2 - PTR1" returns a ptrdiff_t.  */
+
+template<typename E,
+	 typename = decltype (is_offset_type (std::declval<E> ()))>
+constexpr typename std::underlying_type<E>::type
+operator- (E lhs, E rhs)
+{
+  using underlying = typename std::underlying_type<E>::type;
+  return static_cast<underlying> (lhs) - static_cast<underlying> (rhs);
+}
+
+#endif /* COMMON_OFFSET_TYPE_H */