Add rvalue reference tests and docs

This patch adds tests for the initial rvalue reference support patchset.  All
of the new tests are practically mirrored regular references tests and, except
for the demangler ones, are introduced in new files, which are set to be
compiled with -std=gnu++11.  Tested are printing of rvalue reference types and
values, rvalue reference parameters in function overloading, demangling of
function names containing rvalue reference parameters, casts to rvalue
reference types, application of the sizeof operator to rvalue reference types
and values, and support for rvalue references within the gdb python module.

gdb/ChnageLog

	PR gdb/14441
	* NEWS: Mention support for rvalue references in GDB and python.
	* doc/gdb.texinfo (C Plus Plus Expressions): Mention that GDB
	supports both lvalue and rvalue references.

gdb/testsuite/ChangeLog

	PR gdb/14441
	* gdb.cp/demangle.exp: Add rvalue reference tests.
	* gdb.cp/rvalue-ref-casts.cc: New file.
	* gdb.cp/rvalue-ref-casts.exp: New file.
	* gdb.cp/rvalue-ref-overload.cc: New file.
	* gdb.cp/rvalue-ref-overload.exp: New file.
	* gdb.cp/rvalue-ref-params.cc: New file.
	* gdb.cp/rvalue-ref-params.exp: New file.
	* gdb.cp/rvalue-ref-sizeof.cc: New file.
	* gdb.cp/rvalue-ref-sizeof.exp: New file.
	* gdb.cp/rvalue-ref-types.cc: New file.
	* gdb.cp/rvalue-ref-types.exp: New file.
	* gdb.python/py-rvalue-ref-value-cc.cc: New file.
	* gdb.python/py-rvalue-ref-value-cc.exp: New file.

gdb/testsuite/gdb.python/py-rvalue-ref-value-cc.cc

@@ -0,0 +1,59 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2012-2017 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/>.  */
+
+/* Test rvalue references in python.  Based on py-value-cc.cc.  */
+
+#include <utility>
+
+class A
+{
+public:
+  int operator+ (const int a1);
+
+ public:
+  int a;
+};
+
+int
+A::operator+ (const int a1)
+{
+  return a + a1;
+}
+
+class B : public A
+{
+ public:
+  char a;
+};
+
+typedef int *int_ptr;
+
+int
+main ()
+{
+  int val = 10;
+  int &&int_rref = std::move (val);
+  int_ptr ptr = &val;
+  int_ptr &&int_ptr_rref = std::move (ptr);
+
+  B b;
+  b.a = 'b';
+  (&b)->A::a = 100;
+  B &&b_rref = std::move (b);
+
+  return 0; /* Break here.  */
+}

gdb/testsuite/gdb.python/py-rvalue-ref-value-cc.exp

@@ -0,0 +1,57 @@
+# Copyright (C) 2012-2017 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/>.
+
+# This file is part of the GDB testsuite.  It tests the mechanism
+# exposing rvalue reference values to Python.  It is based on
+# gdb.python/py-value-cc.exp.
+
+if {[skip_cplus_tests]} { continue }
+
+standard_testfile .cc
+
+if {[prepare_for_testing $testfile.exp $testfile $srcfile \
+    {debug c++ additional_flags="-std=c++11"}]} {
+    return -1
+}
+
+# Skip all tests if Python scripting is not enabled.
+if {[skip_python_tests]} { continue }
+
+if {![runto_main]} {
+    untested "couldn't run to main"
+   return -1
+}
+
+gdb_breakpoint [gdb_get_line_number "Break here."]
+gdb_continue_to_breakpoint "Break here" ".*Break here.*"
+
+gdb_test "python print (str(gdb.parse_and_eval(\"int_rref\").type))" "int &&"
+gdb_test "python print (str(gdb.parse_and_eval(\"int_rref\").referenced_value().type))" "int"
+gdb_test "python print (str(gdb.parse_and_eval(\"int_rref\").referenced_value()))" "10"
+
+gdb_test "python print (str(gdb.parse_and_eval(\"int_ptr_rref\").dereference().type))" "int"
+gdb_test "python print (str(gdb.parse_and_eval(\"int_ptr_rref\").referenced_value().type))" "int_ptr"
+gdb_test "python print (str(gdb.parse_and_eval(\"int_ptr_rref\").referenced_value().dereference()))" "10"
+gdb_test "python print (str(gdb.parse_and_eval(\"int_ptr_rref\").referenced_value().referenced_value()))" "10"
+
+gdb_test_no_output "python b = gdb.parse_and_eval('b')" "init b"
+gdb_test_no_output "python b_rref = gdb.parse_and_eval('b_rref')" "init b_rref"
+gdb_test_no_output "python b_fields = b.type.fields()" "init b_fields"
+
+gdb_test "python print(b_rref\[b_fields\[1\]\])" "98 'b'" "b_rref.a via field"
+gdb_test "python print(b_rref\[b_fields\[0\]\].type.target())" "A" \
+  "type of b_rref's base class via field"
+gdb_test "python print(b_rref\[b_fields\[0\]\]\['a'\])" "100" \
+  "b_rref.A::a via field"