AArch64: Treat pauth ops as nops on non-pauth systems

Running an address signed binary through GDB on a non pauth system
gives the following error:
Call Frame Instruction op 45 in vendor extension space is not handled on this architecture.

Instead GDB should ignore the op, treating it as a nop.

Add test case for pauth binaries, regardless of whether the target
supports it.

gdb/ChangeLog:

	* aarch64-tdep.c (aarch64_execute_dwarf_cfa_vendor_op): Treat
	DW_CFA_AARCH64_negate_ra_state as nop on non pauth targets.

gdb/testsuite/ChangeLog:

	* gdb.arch/aarch64-pauth.c: New test.
	* gdb.arch/aarch64-pauth.exp: New file.

1 files changed, 36 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.arch/aarch64-pauth.c b/gdb/testsuite/gdb.arch/aarch64-pauth.c
new file mode 100644
index 00000000000..af9bbe4a935
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/aarch64-pauth.c
@@ -0,0 +1,36 @@
+/* This test program is part of GDB, the GNU debugger.
+
+   Copyright 2019 Free Software Foundation, Inc.
+
+   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/>.  */
+
+int
+bar (int b)
+{
+  int x = 1; /* break here.  */
+  return b - x;
+}
+
+int
+foo (int a)
+{
+  int y = bar (9);
+  return a + y;
+}
+
+int
+main ()
+{
+  foo (5);
+}