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-rw-r--r--compilerplugins/clang/mapindex.cxx108
1 files changed, 108 insertions, 0 deletions
diff --git a/compilerplugins/clang/mapindex.cxx b/compilerplugins/clang/mapindex.cxx
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+++ b/compilerplugins/clang/mapindex.cxx
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+/* -*- 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/.
+ */
+#ifndef LO_CLANG_SHARED_PLUGINS
+
+#include <memory>
+#include <cassert>
+#include <string>
+#include <iostream>
+#include <fstream>
+#include <set>
+
+#include "check.hxx"
+#include "plugin.hxx"
+
+/**
+ Look for places we are using map[idx] in a bool context, which allocates an entry in the map, which is sometimes a side-effect we don't want.
+*/
+
+namespace
+{
+class MapIndex : public loplugin::FilteringPlugin<MapIndex>
+{
+public:
+ explicit MapIndex(loplugin::InstantiationData const& data)
+ : FilteringPlugin(data)
+ {
+ }
+
+ virtual void run() override
+ {
+ if (preRun())
+ TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+ }
+
+ bool VisitImplicitCastExpr(const ImplicitCastExpr*);
+ bool VisitMemberExpr(const MemberExpr*);
+};
+
+bool MapIndex::VisitMemberExpr(const MemberExpr* memberExpr)
+{
+ if (ignoreLocation(memberExpr))
+ return true;
+ // operator bool conversion
+ auto conversionDecl = dyn_cast<CXXConversionDecl>(memberExpr->getMemberDecl());
+ if (!conversionDecl || !conversionDecl->getConversionType()->isBooleanType())
+ return true;
+ auto operatorCall = dyn_cast<CXXOperatorCallExpr>(memberExpr->getBase()->IgnoreCasts());
+ if (!operatorCall)
+ return true;
+ if (operatorCall->getOperator() != OverloadedOperatorKind::OO_Subscript)
+ return true;
+ auto tc = loplugin::TypeCheck(operatorCall->getArg(0)->getType());
+ if (!tc.Class("map") && !tc.Class("unordered_map"))
+ return true;
+ report(DiagnosticsEngine::Warning,
+ "will create an empty entry in the map, you sure about that, rather use count()1",
+ operatorCall->getExprLoc());
+ return true;
+}
+
+bool MapIndex::VisitImplicitCastExpr(const ImplicitCastExpr* implicitCastExpr)
+{
+ if (ignoreLocation(implicitCastExpr))
+ {
+ return true;
+ }
+
+ // first cast is some kind of "ToBoolean" cast
+ auto ck = implicitCastExpr->getCastKind();
+ if (ck != CK_MemberPointerToBoolean && ck != CK_PointerToBoolean && ck != CK_IntegralToBoolean
+ && ck != CK_FloatingToBoolean && ck != CK_FloatingComplexToBoolean
+ && ck != CK_IntegralComplexToBoolean)
+ return true;
+
+ // second cast is LValueToRValue
+ implicitCastExpr = dyn_cast<ImplicitCastExpr>(implicitCastExpr->getSubExpr());
+ if (!implicitCastExpr)
+ return true;
+
+ if (implicitCastExpr->getCastKind() != CK_LValueToRValue)
+ return true;
+ auto operatorCall = dyn_cast<CXXOperatorCallExpr>(implicitCastExpr->getSubExpr());
+ if (!operatorCall)
+ return true;
+ if (operatorCall->getOperator() != OverloadedOperatorKind::OO_Subscript)
+ return true;
+ auto tc = loplugin::TypeCheck(operatorCall->getArg(0)->getType());
+ if (!tc.Class("map") && !tc.Class("unordered_map"))
+ return true;
+ report(DiagnosticsEngine::Warning,
+ "will create an empty entry in the map, you sure about that, rather use count()2",
+ implicitCastExpr->getExprLoc());
+ return true;
+}
+
+loplugin::Plugin::Registration<MapIndex> mapindex("mapindex");
+
+} // namespace
+
+#endif // LO_CLANG_SHARED_PLUGINS
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */