new loplugin:redundantpointerops

Change-Id: I8428d86ea9628d69c2b40b36feee3da428a9fe1d
Reviewed-on: https://gerrit.libreoffice.org/41787
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

1 files changed, 129 insertions, 0 deletions

diff --git a/compilerplugins/clang/redundantpointerops.cxx b/compilerplugins/clang/redundantpointerops.cxx
new file mode 100644
index 000000000000..6a88cdb13d70
--- /dev/null
+++ b/compilerplugins/clang/redundantpointerops.cxx
@@ -0,0 +1,129 @@
+/* -*- 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 <cassert>
+#include <string>
+#include <iostream>
+#include <fstream>
+#include <set>
+
+#include <clang/AST/CXXInheritance.h>
+#include "compat.hxx"
+#include "plugin.hxx"
+
+/**
+ * Look for:
+ *     (&x)->y
+ * which can be tranformed to:
+ *      x.y
+ * And
+ *    &*x
+ * which can be:
+ *    x
+ *
+ * @TODO
+ *    (*x).y
+ *  which can be:
+ *    x->y
+ */
+
+namespace {
+
+class RedundantPointerOps:
+    public RecursiveASTVisitor<RedundantPointerOps>, public loplugin::Plugin
+{
+public:
+    explicit RedundantPointerOps(InstantiationData const & data): Plugin(data) {}
+
+    virtual void run() override
+    {
+        TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+    }
+
+    bool VisitFunctionDecl(FunctionDecl const *);
+    bool VisitMemberExpr(MemberExpr const *);
+    bool VisitUnaryOperator(UnaryOperator const *);
+};
+
+bool RedundantPointerOps::VisitFunctionDecl(FunctionDecl const * functionDecl)
+{
+    if (ignoreLocation(functionDecl))
+        return true;
+    //functionDecl->dump();
+    return true;
+}
+
+bool RedundantPointerOps::VisitMemberExpr(MemberExpr const * memberExpr)
+{
+    if (ignoreLocation(memberExpr))
+        return true;
+    if (memberExpr->getLocStart().isMacroID())
+        return true;
+    auto base = memberExpr->getBase()->IgnoreParenImpCasts();
+            //parentStmt(parentStmt(memberExpr))->dump();
+    if (memberExpr->isArrow())
+    {
+        if (auto unaryOp = dyn_cast<UnaryOperator>(base))
+        {
+            if (unaryOp->getOpcode() == UO_AddrOf)
+                report(
+                    DiagnosticsEngine::Warning, "'&' followed by '->', rather use '.'",
+                    memberExpr->getLocStart())
+                    << memberExpr->getSourceRange();
+
+        }
+        else if (auto operatorCallExpr = dyn_cast<CXXOperatorCallExpr>(base))
+        {
+            if (operatorCallExpr->getOperator() == OO_Amp)
+                report(
+                    DiagnosticsEngine::Warning, "'&' followed by '->', rather use '.'",
+                    memberExpr->getLocStart())
+                    << memberExpr->getSourceRange();
+
+        }
+    }
+//    else
+//    {
+//        if (auto unaryOp = dyn_cast<UnaryOperator>(base))
+//        {
+//            if (unaryOp->getOpcode() == UO_Deref)
+//                report(
+//                    DiagnosticsEngine::Warning, "'*' followed by '.', rather use '->'",
+//                    memberExpr->getLocStart())
+//                    << memberExpr->getSourceRange();
+//
+//        }
+//    }
+    return true;
+}
+
+bool RedundantPointerOps::VisitUnaryOperator(UnaryOperator const * unaryOperator)
+{
+    if (ignoreLocation(unaryOperator))
+        return true;
+    if (unaryOperator->getLocStart().isMacroID())
+        return true;
+    if (unaryOperator->getOpcode() != UO_Deref)
+        return true;
+    auto innerOp = dyn_cast<UnaryOperator>(unaryOperator->getSubExpr()->IgnoreParenImpCasts());
+    if (!innerOp || innerOp->getOpcode() != UO_AddrOf)
+        return true;
+
+    report(
+        DiagnosticsEngine::Warning, "'&' followed by '*', rather use '.'",
+        unaryOperator->getLocStart())
+        << unaryOperator->getSourceRange();
+    return true;
+}
+
+loplugin::Plugin::Registration< RedundantPointerOps > X("redundantpointerops");
+
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */