Some loplugin:revisibility clean-up

Stumbled across such redundant visibility re-specifications when looking at the
odd case of cppu_unsatisfied_iquery_msg declared CPPU_DLLPUBLIC in
cppu/source/cppu/cppu_opt.cxx and used in inline code in
include/com/sun/star/uno/Reference.hxx with only a declaration lacking
CPPU_DLLPUBLIC visible, and wondering how that actually works on Windows.

However, this plugin is probably not worth it being run all the time, so
committing it to compilerplugins/clang/store/.

Change-Id: Ibc3c4e7499213de1b419ce7eb85455cb832e1510

1 files changed, 71 insertions, 0 deletions

diff --git a/compilerplugins/clang/store/revisibility.cxx b/compilerplugins/clang/store/revisibility.cxx
new file mode 100644
index 000000000000..11e3cc89ee5e
--- /dev/null
+++ b/compilerplugins/clang/store/revisibility.cxx
@@ -0,0 +1,71 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * 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 "plugin.hxx"
+
+// Find function declarations that redundantly re-specify a visibility attribute
+// (via SAL_DLLPUBLIC_EXPORT etc.) that was already specified with a previous
+// declaration of that function.  But MSVC wants consistency of __declspec
+// across friend declarations, so just ignore those for now.
+
+namespace {
+
+bool hasExplicitVisibilityAttr(Decl const * decl) {
+    VisibilityAttr const * attr = decl->getAttr<VisibilityAttr>();
+    return attr != nullptr && !attr->isInherited();
+}
+
+bool isFriendDecl(Decl const * decl) {
+    return decl->getFriendObjectKind() != Decl::FOK_None;
+}
+
+class ReVisibility:
+    public RecursiveASTVisitor<ReVisibility>, public loplugin::Plugin
+{
+public:
+    explicit ReVisibility(InstantiationData const & data): Plugin(data) {}
+
+    void run() override
+    { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
+
+    bool VisitFunctionDecl(FunctionDecl const * decl);
+};
+
+bool ReVisibility::VisitFunctionDecl(FunctionDecl const * decl) {
+    if (!ignoreLocation(decl) && hasExplicitVisibilityAttr(decl)
+        && !isFriendDecl(decl))
+    {
+        for (Decl const * p = decl;;) {
+            p = p->getPreviousDecl();
+            if (p == nullptr) {
+                break;
+            }
+            if (hasExplicitVisibilityAttr(p) && !isFriendDecl(p)) {
+                report(
+                    DiagnosticsEngine::Warning,
+                    "Redundant visibility re-declaration",
+                    decl->getAttr<VisibilityAttr>()->getLocation())
+                    << decl->getAttr<VisibilityAttr>()->getRange();
+                report(
+                    DiagnosticsEngine::Note,
+                    "Previous visibility declaration is here",
+                    p->getAttr<VisibilityAttr>()->getLocation())
+                    << p->getAttr<VisibilityAttr>()->getRange();
+                break;
+            }
+        }
+    }
+    return true;
+}
+
+loplugin::Plugin::Registration<ReVisibility> X("revisibility");
+
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */