new loplugin:noexceptmove

idea from mike kaganski

look for places where we can mark move operators as noexcept, which
makes some STL operations more efficient

Change-Id: Id732b89d1fcadd5ceb0ea2b9d159fed06136330f
Reviewed-on: https://gerrit.libreoffice.org/78251
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

1 files changed, 102 insertions, 0 deletions

diff --git a/compilerplugins/clang/test/noexceptmove.cxx b/compilerplugins/clang/test/noexceptmove.cxx
new file mode 100644
index 000000000000..fda58deae403
--- /dev/null
+++ b/compilerplugins/clang/test/noexceptmove.cxx
@@ -0,0 +1,102 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+#include "config_clang.h"
+
+// clang before V9 does not have API to report exception spec type
+#if CLANG_VERSION >= 90000
+
+namespace test1
+{
+class Mapping
+{
+    char* m_pMapping;
+
+    // expected-error@+1 {{move constructor can be noexcept [loplugin:noexceptmove]}}
+    Mapping(Mapping&& other)
+        : m_pMapping(other.m_pMapping)
+    {
+        other.m_pMapping = nullptr;
+    }
+
+    // expected-error@+1 {{move operator= can be noexcept [loplugin:noexceptmove]}}
+    Mapping& operator=(Mapping&& other)
+    {
+        m_pMapping = other.m_pMapping;
+        other.m_pMapping = nullptr;
+        return *this;
+    }
+};
+};
+
+// No warning expected, because calling throwing function.
+namespace test2
+{
+void foo() noexcept(false);
+
+class Bar
+{
+    Bar(Bar&&) { foo(); }
+};
+};
+
+// no warning expected, because calling throwing constructor
+namespace test3
+{
+struct Foo
+{
+    Foo() noexcept(false);
+};
+class Bar
+{
+    Bar(Bar&&) { Foo aFoo; }
+};
+
+class Bar2
+{
+    Foo m_foo;
+
+    Bar2(Bar2&&) {}
+};
+};
+
+// No warning expected, because calling throwing destructor.
+namespace test4
+{
+struct Foo
+{
+    ~Foo() noexcept(false);
+};
+
+class Bar
+{
+    Bar(Bar&&) { Foo aFoo; }
+};
+};
+
+// Check for calls to defaulted constructors.
+namespace test5
+{
+struct Foo
+{
+    Foo() = default; // non-throwing
+};
+class Bar
+{
+    Bar(Bar&&) // expected-error {{move constructor can be noexcept [loplugin:noexceptmove]}}
+    {
+        Foo aFoo;
+        (void)aFoo;
+    }
+};
+};
+
+#else
+// expected-no-diagnostics
+#endif // CLANG_VERSION
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */