compilerplugins/clang/stringconcatauto.cxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * Based on LLVM/Clang.
   6  *
   7  * This file is distributed under the University of Illinois Open Source
   8  * License. See LICENSE.TXT for details.
   9  *
  10  */
  11
  12 /*
  13 This is a compile check.
  14
  15 Warns about 'auto' declarations becoming rtl::OUStringConcat, such as
  16 auto str = "string" + OUString::number( 10 );
  17 The type of the expression is rtl::OUStringConcat and those refer to temporaries
  18 and so their lifecycle should not extend the lifecycle of those temporaries.
  19 */
  20
  21 #ifndef LO_CLANG_SHARED_PLUGINS
  22
  23 #include "plugin.hxx"
  24 #include "check.hxx"
  25
  26 namespace loplugin
  27 {
  28
  29 class StringConcatAuto
  30     : public FilteringPlugin< StringConcatAuto >
  31     {
  32     public:
  33         StringConcatAuto( const InstantiationData& data );
  34         virtual void run() override;
  35         bool shouldVisitTemplateInstantiations () const { return true; }
  36         bool VisitVarDecl( const VarDecl* decl );
  37         bool VisitFunctionDecl( const FunctionDecl* decl );
  38     private:
  39         enum class Check { Var, Return };
  40         bool checkDecl( const DeclaratorDecl* decl, const QualType type, const SourceRange& range, Check check );
  41     };
  42
  43 StringConcatAuto::StringConcatAuto( const InstantiationData& data )
  44     : FilteringPlugin( data )
  45     {
  46     }
  47
  48 void StringConcatAuto::run()
  49     {
  50     TraverseDecl( compiler.getASTContext().getTranslationUnitDecl());
  51     }
  52
  53 bool StringConcatAuto::VisitVarDecl( const VarDecl* decl )
  54     {
  55     return checkDecl( decl, decl->getType(),
  56         decl->getTypeSourceInfo()
  57             ? decl->getTypeSourceInfo()->getTypeLoc().getSourceRange()
  58             : decl->getSourceRange(),
  59         Check::Var );
  60     }
  61
  62 bool StringConcatAuto::VisitFunctionDecl( const FunctionDecl* decl )
  63     {
  64     return checkDecl( decl, decl->getReturnType(), decl->getReturnTypeSourceRange(), Check::Return );
  65     }
  66
  67 bool StringConcatAuto::checkDecl( const DeclaratorDecl* decl, QualType type, const SourceRange& range, Check check )
  68     {
  69     if( ignoreLocation( decl ))
  70         return true;
  71     if( isa< ParmVarDecl >( decl )) // parameters should be fine, temporaries should exist during the call
  72         return true;
  73     std::string fileName = getFilenameOfLocation(
  74         compiler.getSourceManager().getSpellingLoc(compat::getBeginLoc(decl))).str();
  75     loplugin::normalizeDotDotInFilePath(fileName);
  76     if (loplugin::isSamePathname(fileName, SRCDIR "/include/rtl/string.hxx")
  77         || loplugin::isSamePathname(fileName, SRCDIR "/include/rtl/ustring.hxx")
  78         || loplugin::isSamePathname(fileName, SRCDIR "/include/rtl/strbuf.hxx")
  79         || loplugin::isSamePathname(fileName, SRCDIR "/include/rtl/ustrbuf.hxx")
  80         || loplugin::isSamePathname(fileName, SRCDIR "/include/rtl/stringconcat.hxx"))
  81         return true;
  82     auto const tc = loplugin::TypeCheck( type.getNonReferenceType().getCanonicalType());
  83     const char* typeString = nullptr;
  84     if( tc.Struct("OUStringConcat").Namespace("rtl").GlobalNamespace())
  85         typeString = "OUString";
  86     else if( tc.Struct("OStringConcat").Namespace("rtl").GlobalNamespace())
  87         typeString = "OString";
  88     else if( tc.Struct("OUStringNumber").Namespace("rtl").GlobalNamespace())
  89         typeString = "OUString";
  90     else if( tc.Struct("OStringNumber").Namespace("rtl").GlobalNamespace())
  91         typeString = "OString";
  92     else
  93         return true;
  94     report( DiagnosticsEngine::Warning,
  95         check == Check::Var
  96             ? "creating a variable of type %0 will make it reference temporaries"
  97             : "returning a variable of type %0 will make it reference temporaries",
  98         decl->getLocation())
  99         << type;
 100     report( DiagnosticsEngine::Note,
 101         "use %0 instead",
 102         range.getBegin())
 103         << typeString
 104         << FixItHint::CreateReplacement( range, typeString );
 105     return true;
 106     }
 107
 108 static Plugin::Registration< StringConcatAuto > stringconcatauto( "stringconcatauto" );
 109
 110 } // namespace
 111
 112 #endif // LO_CLANG_SHARED_PLUGINS
 113
 114 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */