nvptx, libgcc: Stub unwinding implementation

[Thomas Schwinge <thomas@codesourcery.com>]

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Hi!

We've been (t)asked to enable (portions of) GCC/Fortran I/O for nvptx
offloading, which means building a normal (non-'LIBGFOR_MINIMAL')
configuration of libgfortran.  One prerequisite patch, based on WIP work
by Andrew Stubbs, is: "nvptx, libgcc: Stub unwinding implementation", see
attached.  This I've just pushed to devel/omp/gcc-12 branch in
commit 26d3146736218ccaaaafdaba4da1edf969bc190d, and would like to push
to master branch once other pending GCC patches have been accepted.


Grüße
 Thomas


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From 26d3146736218ccaaaafdaba4da1edf969bc190d Mon Sep 17 00:00:00 2001
From: Thomas Schwinge <thomas@codesourcery.com>
Date: Wed, 21 Sep 2022 18:58:34 +0200
Subject: [PATCH] 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@codesourcery.com>
---
 libgcc/ChangeLog.omp               |  6 +++++
 libgcc/config/nvptx/t-nvptx        |  3 ++-
 libgcc/config/nvptx/unwind-nvptx.c | 36 ++++++++++++++++++++++++++++++
 3 files changed, 44 insertions(+), 1 deletion(-)
 create mode 100644 libgcc/config/nvptx/unwind-nvptx.c

diff --git a/libgcc/ChangeLog.omp b/libgcc/ChangeLog.omp
index 2e7bf5cc029..c46f49bf5b7 100644
--- a/libgcc/ChangeLog.omp
+++ b/libgcc/ChangeLog.omp
@@ -1,3 +1,9 @@
+2023-01-20  Thomas Schwinge  <thomas@codesourcery.com>
+	    Andrew Stubbs  <ams@codesourcery.com>
+
+	* config/nvptx/t-nvptx: Add unwind-nvptx.c.
+	* config/nvptx/unwind-nvptx.c: New file.
+
 2023-01-20  Thomas Schwinge  <thomas@codesourcery.com>
 
 	* config/nvptx/crtstuff.c ["mgomp"]
diff --git a/libgcc/config/nvptx/t-nvptx b/libgcc/config/nvptx/t-nvptx
index 9a0454c3a4d..1845a38a35e 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
 
 LIB2ADDEH=
 LIB2FUNCS_EXCLUDE=
diff --git a/libgcc/config/nvptx/unwind-nvptx.c b/libgcc/config/nvptx/unwind-nvptx.c
new file mode 100644
index 00000000000..c657b2af6f3
--- /dev/null
+++ b/libgcc/config/nvptx/unwind-nvptx.c
@@ -0,0 +1,36 @@
+/* Stub unwinding implementation.
+
+   Copyright (C) 2019-2023 Free Software Foundation, Inc.
+
+   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;
+}
-- 
2.25.1