--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/ada/sigtramp.h	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,79 @@
+/****************************************************************************
+ *                                                                          *
+ *                         GNAT COMPILER COMPONENTS                         *
+ *                                                                          *
+ *                             S I G T R A M P                              *
+ *                                                                          *
+ *                              C Header File                               *
+ *                                                                          *
+ *          Copyright (C) 2011-2015, Free Software Foundation, Inc.         *
+ *                                                                          *
+ * GNAT is free software;  you can  redistribute it  and/or modify it under *
+ * terms of the  GNU General Public License as published  by the Free Soft- *
+ * ware  Foundation;  either version 3,  or (at your option) any later ver- *
+ * sion.  GNAT is distributed in the hope that it will be useful, but WITH- *
+ * OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY *
+ * or FITNESS FOR A PARTICULAR PURPOSE.                                     *
+ *                                                                          *
+ * As a special exception 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/>.                                          *
+ *                                                                          *
+ * GNAT was originally developed  by the GNAT team at  New York University. *
+ * Extensive contributions were provided by Ada Core Technologies Inc.      *
+ *                                                                          *
+ ****************************************************************************/
+
+/* On targets where this is implemented, we resort to a signal trampoline to
+   set up the DWARF Call Frame Information that lets unwinders walk through
+   the signal frame up into the interrupted user code.  This file introduces
+   the relevant declarations.  It should only be #included on targets that do
+   implement the signal trampoline.  */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* This typedef signature sometimes conflicts with the sighandler_t from
+   system headers so call it something unique.  */
+typedef void __sigtramphandler_t (int signo, void *siginfo, void *sigcontext);
+
+/* The vxsim target has a different sigcontext structure than the one we're
+   compiling the run-time with. We thus need to adjust it in this case */
+#if defined(__vxworks) && (defined (__i386__) || defined (__x86_64__)) && !defined (VTHREADS)
+#define __HANDLE_VXSIM_SC
+extern void __gnat_set_is_vxsim(int val);
+#endif
+
+extern void __gnat_sigtramp (int signo, void *siginfo, void *sigcontext,
+			     __sigtramphandler_t * handler);
+
+/* The signal trampoline is to be called from an established signal handler.
+   It sets up the DWARF CFI and calls HANDLER (SIGNO, SIGINFO, SIGCONTEXT).
+
+   The trampoline construct makes it so that the unwinder jumps over it + the
+   signal handler + the kernel frame.  For a typical backtrace from the raise
+   function:
+
+     #0  __gnat_Unwind_RaiseException
+     #1  Raise_From_Signal_Handler
+     #2  __gnat_map_signal
+     #3  __gnat_sigtramp
+     #4  __gnat_error_handler
+     #5  <kernel frame>
+     #6  interrupted function
+
+   The unwinder will unwind frames 0, 1 and 2 as usual.  But the CFI of frame
+   3 is set up as if the caller of frame 3 was frame 6 so, when frame 3 is
+   unwound, the unwinder ends up in frame 6 directly.  It's possible to do so
+   because the kernel has saved the context of frame 6 and passed it on to
+   __gnat_error_handler and __gnat_sigtramp.  */
+
+#ifdef __cplusplus
+}
+#endif