1 files changed, 114 insertions, 0 deletions
diff --git a/compilerplugins/clang/stringconcatauto.cxx b/compilerplugins/clang/stringconcatauto.cxx
new file mode 100644
index 000000000..c7460cfcc
--- /dev/null
+++ b/compilerplugins/clang/stringconcatauto.cxx
@@ -0,0 +1,114 @@
+/* -*- 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.
+ *
+ */
+
+/*
+This is a compile check.
+
+Warns about 'auto' declarations becoming rtl::OUStringConcat, such as
+auto str = "string" + OUString::number( 10 );
+The type of the expression is rtl::OUStringConcat and those refer to temporaries
+and so their lifecycle should not extend the lifecycle of those temporaries.
+*/
+
+#ifndef LO_CLANG_SHARED_PLUGINS
+
+#include "plugin.hxx"
+#include "check.hxx"
+
+namespace loplugin
+{
+
+class StringConcatAuto
+    : public FilteringPlugin< StringConcatAuto >
+    {
+    public:
+        StringConcatAuto( const InstantiationData& data );
+        virtual void run() override;
+        bool shouldVisitTemplateInstantiations () const { return true; }
+        bool VisitVarDecl( const VarDecl* decl );
+        bool VisitFunctionDecl( const FunctionDecl* decl );
+    private:
+        enum class Check { Var, Return };
+        bool checkDecl( const DeclaratorDecl* decl, const QualType type, const SourceRange& range, Check check );
+    };
+
+StringConcatAuto::StringConcatAuto( const InstantiationData& data )
+    : FilteringPlugin( data )
+    {
+    }
+
+void StringConcatAuto::run()
+    {
+    TraverseDecl( compiler.getASTContext().getTranslationUnitDecl());
+    }
+
+bool StringConcatAuto::VisitVarDecl( const VarDecl* decl )
+    {
+    return checkDecl( decl, decl->getType(),
+        decl->getTypeSourceInfo()
+            ? decl->getTypeSourceInfo()->getTypeLoc().getSourceRange()
+            : decl->getSourceRange(),
+        Check::Var );
+    }
+
+bool StringConcatAuto::VisitFunctionDecl( const FunctionDecl* decl )
+    {
+    return checkDecl( decl, decl->getReturnType(), decl->getReturnTypeSourceRange(), Check::Return );
+    }
+
+bool StringConcatAuto::checkDecl( const DeclaratorDecl* decl, QualType type, const SourceRange& range, Check check )
+    {
+    if( ignoreLocation( decl ))
+        return true;
+    if( isa< ParmVarDecl >( decl )) // parameters should be fine, temporaries should exist during the call
+        return true;
+    std::string fileName = getFilenameOfLocation(
+        compiler.getSourceManager().getSpellingLoc(compat::getBeginLoc(decl))).str();
+    loplugin::normalizeDotDotInFilePath(fileName);
+    if (loplugin::isSamePathname(fileName, SRCDIR "/include/rtl/string.hxx")
+        || loplugin::isSamePathname(fileName, SRCDIR "/include/rtl/ustring.hxx")
+        || loplugin::isSamePathname(fileName, SRCDIR "/include/rtl/strbuf.hxx")
+        || loplugin::isSamePathname(fileName, SRCDIR "/include/rtl/ustrbuf.hxx")
+        || loplugin::isSamePathname(fileName, SRCDIR "/include/rtl/stringconcat.hxx"))
+        return true;
+    auto const tc = loplugin::TypeCheck( type.getNonReferenceType().getCanonicalType());
+    const char* typeString = nullptr;
+    if( tc.Struct("OUStringConcat").Namespace("rtl").GlobalNamespace())
+        typeString = "OUString";
+    else if( tc.Struct("OStringConcat").Namespace("rtl").GlobalNamespace())
+        typeString = "OString";
+    else if( tc.Struct("OUStringNumber").Namespace("rtl").GlobalNamespace())
+        typeString = "OUString";
+    else if( tc.Struct("OStringNumber").Namespace("rtl").GlobalNamespace())
+        typeString = "OString";
+    else
+        return true;
+    report( DiagnosticsEngine::Warning,
+        check == Check::Var
+            ? "creating a variable of type %0 will make it reference temporaries"
+            : "returning a variable of type %0 will make it reference temporaries",
+        decl->getLocation())
+        << type;
+    report( DiagnosticsEngine::Note,
+        "use %0 instead",
+        range.getBegin())
+        << typeString
+        << FixItHint::CreateReplacement( range, typeString );
+    return true;
+    }
+
+static Plugin::Registration< StringConcatAuto > stringconcatauto( "stringconcatauto" );
+
+} // namespace
+
+#endif // LO_CLANG_SHARED_PLUGINS
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */