new loplugin:moveparam

Look for places where we can pass Primitive2DContainer by move reference
and so avoid unnecessary copies.

Change-Id: I1db167feba6d1a616ca6fc39778118ae20106bd1
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/122964
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

2 files changed, 170 insertions, 0 deletions

diff --git a/compilerplugins/clang/moveparam.cxx b/compilerplugins/clang/moveparam.cxx
new file mode 100644
index 000000000000..46816184071f
--- /dev/null
+++ b/compilerplugins/clang/moveparam.cxx
@@ -0,0 +1,127 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * Based on LLVM/Clang.
+ *
+ * This file is distributed under the University of Illinois Open Source
+ * License. See LICENSE.TXT for details.
+ *
+ */
+
+#include <cassert>
+#include <string>
+#include <iostream>
+#include <fstream>
+#include <set>
+#include <unordered_set>
+#include "plugin.hxx"
+#include "check.hxx"
+
+/*
+Look for places where we can pass by Primitive2DContainer param and so avoid
+unnecessary copies.
+*/
+
+namespace
+{
+class MoveParam : public loplugin::FilteringPlugin<MoveParam>
+{
+public:
+    explicit MoveParam(loplugin::InstantiationData const& data)
+        : FilteringPlugin(data)
+    {
+    }
+
+    virtual bool preRun() override { return true; }
+
+    virtual void run() override
+    {
+        if (preRun())
+            TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+    }
+
+    bool PreTraverseConstructorInitializer(CXXCtorInitializer*);
+    bool PostTraverseConstructorInitializer(CXXCtorInitializer*, bool);
+    bool TraverseConstructorInitializer(CXXCtorInitializer*);
+    bool VisitCXXOperatorCallExpr(const CXXOperatorCallExpr*);
+};
+
+bool MoveParam::VisitCXXOperatorCallExpr(const CXXOperatorCallExpr* callExpr)
+{
+    if (ignoreLocation(callExpr))
+        return true;
+    if (!callExpr->isAssignmentOp())
+        return true;
+    if (!loplugin::TypeCheck(callExpr->getType())
+             .Class("Primitive2DContainer")
+             .Namespace("primitive2d"))
+        return true;
+    auto declRef = dyn_cast<DeclRefExpr>(callExpr->getArg(1)->IgnoreParenImpCasts());
+    if (!declRef)
+        return true;
+
+    auto parmVarDecl = dyn_cast_or_null<ParmVarDecl>(declRef->getDecl());
+    if (!parmVarDecl)
+        return true;
+
+    if (!loplugin::TypeCheck(parmVarDecl->getType()).LvalueReference().Const())
+        return true;
+
+    report(DiagnosticsEngine::Warning, "rather use move && param", compat::getBeginLoc(callExpr));
+
+    return true;
+}
+
+bool MoveParam::PreTraverseConstructorInitializer(CXXCtorInitializer* init)
+{
+    if (ignoreLocation(init->getSourceLocation()))
+        return true;
+    const FieldDecl* fieldDecl = init->getAnyMember();
+    if (!fieldDecl)
+        return true;
+
+    auto dc = loplugin::TypeCheck(fieldDecl->getType())
+                  .Class("Primitive2DContainer")
+                  .Namespace("primitive2d")
+                  .Namespace("drawinglayer")
+                  .GlobalNamespace();
+    if (!dc)
+        return true;
+
+    auto constructExpr = dyn_cast_or_null<CXXConstructExpr>(init->getInit());
+    if (!constructExpr || constructExpr->getNumArgs() != 1)
+        return true;
+
+    auto declRef = dyn_cast<DeclRefExpr>(constructExpr->getArg(0)->IgnoreParenImpCasts());
+    if (!declRef)
+        return true;
+
+    auto parmVarDecl = dyn_cast_or_null<ParmVarDecl>(declRef->getDecl());
+    if (!parmVarDecl)
+        return true;
+
+    if (!loplugin::TypeCheck(parmVarDecl->getType()).LvalueReference().Const())
+        return true;
+
+    report(DiagnosticsEngine::Warning, "rather use move && param", init->getSourceLocation());
+
+    return true;
+}
+bool MoveParam::PostTraverseConstructorInitializer(CXXCtorInitializer*, bool) { return true; }
+bool MoveParam::TraverseConstructorInitializer(CXXCtorInitializer* init)
+{
+    bool ret = true;
+    if (PreTraverseConstructorInitializer(init))
+    {
+        ret = FilteringPlugin<MoveParam>::TraverseConstructorInitializer(init);
+        PostTraverseConstructorInitializer(init, ret);
+    }
+    return ret;
+}
+
+loplugin::Plugin::Registration<MoveParam> moveparam("moveparam", true);
+
+} // namespace
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/test/moveparam.cxx b/compilerplugins/clang/test/moveparam.cxx
new file mode 100644
index 000000000000..c90e8ae4bbd4
--- /dev/null
+++ b/compilerplugins/clang/test/moveparam.cxx
@@ -0,0 +1,43 @@
+/* -*- 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"
+#include "o3tl/cow_wrapper.hxx"
+
+namespace drawinglayer::primitive2d
+{
+class Primitive2DContainer
+{
+};
+}
+
+struct Foo
+{
+    drawinglayer::primitive2d::Primitive2DContainer maMine;
+
+    // expected-error@+2 {{rather use move && param [loplugin:moveparam]}}
+    Foo(drawinglayer::primitive2d::Primitive2DContainer const& rContainer)
+        : maMine(rContainer)
+    {
+    }
+
+    // no warning expected
+    Foo(drawinglayer::primitive2d::Primitive2DContainer&& rContainer)
+        : maMine(rContainer)
+    {
+    }
+
+    void foo1(const drawinglayer::primitive2d::Primitive2DContainer& rContainer)
+    {
+        // expected-error@+1 {{rather use move && param [loplugin:moveparam]}}
+        maMine = rContainer;
+    }
+};
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */