[PATCH v2] [libatomic] Add RTEMS support

[Sebastian Huber]

v2: Do not use architecture configuration due to broken ARM libatomic
support.

gcc/

	* config/rtems.h (LIB_SPEC): Add -latomic.

libatomic/

	* configure.tgt (*-*-rtems*): New supported target.
	* config/rtems/host-config.h: New file.
	* config/rtems/lock.c: Likewise.
---
 gcc/config/rtems.h                   |  2 +-
 libatomic/config/rtems/host-config.h | 41 ++++++++++++++++++++++++++++++++++++
 libatomic/config/rtems/lock.c        | 37 ++++++++++++++++++++++++++++++++
 libatomic/configure.tgt              | 10 +++++++++
 4 files changed, 89 insertions(+), 1 deletion(-)
 create mode 100644 libatomic/config/rtems/host-config.h
 create mode 100644 libatomic/config/rtems/lock.c

diff --git a/gcc/config/rtems.h b/gcc/config/rtems.h
index f13f72f..e005547 100644
--- a/gcc/config/rtems.h
+++ b/gcc/config/rtems.h
@@ -45,6 +45,6 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define LIB_SPEC "%{!qrtems: " STD_LIB_SPEC "} " \
 "%{!nostdlib: %{qrtems: --start-group \
  -lrtemsbsp -lrtemscpu \
- -lc -lgcc --end-group %{!qnolinkcmds: -T linkcmds%s}}}"
+ -latomic -lc -lgcc --end-group %{!qnolinkcmds: -T linkcmds%s}}}"
 
 #define TARGET_POSIX_IO
diff --git a/libatomic/config/rtems/host-config.h b/libatomic/config/rtems/host-config.h
new file mode 100644
index 0000000..d11e9ef
--- /dev/null
+++ b/libatomic/config/rtems/host-config.h
@@ -0,0 +1,41 @@
+/* Copyright (C) 2016 Free Software Foundation, Inc.
+   Contributed by Sebastian Huber <sebastian.huber at embedded-brains.de>.
+
+   This file is part of the GNU Atomic Library (libatomic).
+
+   Libatomic 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.
+
+   Libatomic 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.
+
+   Under Section 7 of GPL version 3, you are granted additional
+   permissions described in the GCC Runtime Library Exception, version
+   3.1, as published by the Free Software Foundation.
+
+   You should have received a copy of the GNU General Public License and
+   a copy of the GCC Runtime Library Exception along with this program;
+   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* Included after all more target-specific host-config.h.  */
+
+#include <machine/_libatomic.h>
+
+static inline UWORD
+protect_start (void *ptr)
+{
+  return _Libatomic_Protect_start (ptr);
+}
+
+static inline void
+protect_end (void *ptr, UWORD isr_level)
+{
+  _Libatomic_Protect_end (ptr, isr_level);
+}
+
+#include_next <host-config.h>
diff --git a/libatomic/config/rtems/lock.c b/libatomic/config/rtems/lock.c
new file mode 100644
index 0000000..f999f9b
--- /dev/null
+++ b/libatomic/config/rtems/lock.c
@@ -0,0 +1,37 @@
+/* Copyright (C) 2016 Free Software Foundation, Inc.
+   Contributed by Sebastian Huber <sebastian.huber at embedded-brains.de>.
+
+   This file is part of the GNU Atomic Library (libatomic).
+
+   Libatomic 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.
+
+   Libatomic 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.
+
+   Under Section 7 of GPL version 3, you are granted additional
+   permissions described in the GCC Runtime Library Exception, version
+   3.1, as published by the Free Software Foundation.
+
+   You should have received a copy of the GNU General Public License and
+   a copy of the GCC Runtime Library Exception along with this program;
+   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include "libatomic_i.h"
+
+void
+libat_lock_n (void *ptr, size_t n)
+{
+  _Libatomic_Lock_n (ptr, n);
+}
+
+void
+libat_unlock_n (void *ptr, size_t n)
+{
+  _Libatomic_Unlock_n (ptr, n);
+}
diff --git a/libatomic/configure.tgt b/libatomic/configure.tgt
index c5470d7..eab2765 100644
--- a/libatomic/configure.tgt
+++ b/libatomic/configure.tgt
@@ -26,6 +26,10 @@
 # Map the target cpu to an ARCH sub-directory.  At the same time,
 # work out any special compilation flags as necessary.
 
+# Give operating systems the opportunity to discard XCFLAGS modifications based
+# on ${target_cpu}.  For example to allow proper use of multilibs.
+configure_tgt_pre_target_cpu_XCFLAGS="${XCFLAGS}"
+
 case "${target_cpu}" in
   alpha*)
 	# fenv.c needs this option to generate inexact exceptions.
@@ -128,6 +132,12 @@ case "${target}" in
             ;;
         esac
 	;;
+
+  *-*-rtems*)
+	XCFLAGS="${configure_tgt_pre_target_cpu_XCFLAGS}"
+	config_path="rtems"
+	;;
+
   *-*-elf*)
 	# ??? No target OS.  We could be targeting bare-metal kernel-mode,
 	# or user-mode for some custom OS.  If the target supports TAS,
-- 
1.8.4.5