nvptx, libgcc: Stub unwinding implementation

Adding stub '_Unwind_Backtrace', '_Unwind_GetIPInfo' functions is necessary
for linking libbacktrace, as a normal (non-'LIBGFOR_MINIMAL') configuration
of libgfortran wants to do, for example.

The file 'libgcc/config/nvptx/unwind-nvptx.c' is copied from
'libgcc/config/gcn/unwind-gcn.c'.

libgcc/ChangeLog:

	* config/nvptx/t-nvptx: Add unwind-nvptx.c.
	* config/nvptx/unwind-nvptx.c: New file.

Co-authored-by: Andrew Stubbs <ams@gcc.gnu.org>

2 files changed, 39 insertions, 1 deletions

diff --git a/libgcc/config/nvptx/t-nvptx b/libgcc/config/nvptx/t-nvptx
index 260ed63..1ff574c 100644
--- a/libgcc/config/nvptx/t-nvptx
+++ b/libgcc/config/nvptx/t-nvptx
@@ -1,6 +1,7 @@
 LIB2ADD=$(srcdir)/config/nvptx/reduction.c \
 	$(srcdir)/config/nvptx/mgomp.c \
-	$(srcdir)/config/nvptx/atomic.c
+	$(srcdir)/config/nvptx/atomic.c \
+	$(srcdir)/config/nvptx/unwind-nvptx.c
 
 # Until we have libstdc++-v3/libsupc++ proper.
 LIB2ADD += $(srcdir)/c++-minimal/guard.c
diff --git a/libgcc/config/nvptx/unwind-nvptx.c b/libgcc/config/nvptx/unwind-nvptx.c
new file mode 100644
index 0000000..d08ba26
--- /dev/null
+++ b/libgcc/config/nvptx/unwind-nvptx.c
@@ -0,0 +1,37 @@
+/* Stub unwinding implementation.
+
+   Copyright (C) 2019-2024 Free Software Foundation, Inc.
+   Contributed by Mentor Graphics
+
+   This file 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, or (at your option) any
+   later version.
+
+   This file 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 "unwind.h"
+
+_Unwind_Reason_Code
+_Unwind_Backtrace(_Unwind_Trace_Fn trace, void * trace_argument)
+{
+  return 0;
+}
+
+_Unwind_Ptr
+_Unwind_GetIPInfo (struct _Unwind_Context *c, int *ip_before_insn)
+{
+  return 0;
+}