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 "config_clang.h"
  24
  25 #include "plugin.hxx"
  26 #include "check.hxx"
  27
  28 namespace loplugin
  29 {
  30
  31 class StringConcatAuto
  32     : public FilteringPlugin< StringConcatAuto >
  33     {
  34     public:
  35         StringConcatAuto( const InstantiationData& data );
  36         virtual void run() override;
  37         bool shouldVisitTemplateInstantiations () const { return true; }
  38         bool VisitVarDecl( const VarDecl* decl );
  39         bool VisitFunctionDecl( const FunctionDecl* decl );
  40     private:
  41         enum class Check { Var, Return };
  42         bool checkDecl( const DeclaratorDecl* decl, const QualType type, const SourceRange& range, Check check );
  43     };
  44
  45 StringConcatAuto::StringConcatAuto( const InstantiationData& data )
  46     : FilteringPlugin( data )
  47     {
  48     }
  49
  50 void StringConcatAuto::run()
  51     {
  52     TraverseDecl( compiler.getASTContext().getTranslationUnitDecl());
  53     }
  54
  55 bool StringConcatAuto::VisitVarDecl( const VarDecl* decl )
  56     {
  57     return checkDecl( decl, decl->getType(),
  58         decl->getTypeSourceInfo()
  59             ? decl->getTypeSourceInfo()->getTypeLoc().getSourceRange()
  60             : decl->getSourceRange(),
  61         Check::Var );
  62     }
  63
  64 bool StringConcatAuto::VisitFunctionDecl( const FunctionDecl* decl )
  65     {
  66     return checkDecl( decl, decl->getReturnType(), decl->getReturnTypeSourceRange(), Check::Return );
  67     }
  68
  69 bool StringConcatAuto::checkDecl( const DeclaratorDecl* decl, QualType type, const SourceRange& range, Check check )
  70     {
  71     if( ignoreLocation( decl ))
  72         return true;
  73     if( isa< ParmVarDecl >( decl )) // parameters should be fine, temporaries should exist during the call
  74         return true;
  75     std::string fileName = getFilenameOfLocation(
  76         compiler.getSourceManager().getSpellingLoc(decl->getBeginLoc())).str();
  77     loplugin::normalizeDotDotInFilePath(fileName);
  78     if (loplugin::isSamePathname(fileName, SRCDIR "/include/rtl/string.hxx")
  79         || loplugin::isSamePathname(fileName, SRCDIR "/include/rtl/ustring.hxx")
  80         || loplugin::isSamePathname(fileName, SRCDIR "/include/rtl/strbuf.hxx")
  81         || loplugin::isSamePathname(fileName, SRCDIR "/include/rtl/ustrbuf.hxx")
  82         || loplugin::isSamePathname(fileName, SRCDIR "/include/rtl/stringconcat.hxx"))
  83         return true;
  84     auto const tc = loplugin::TypeCheck( type.getNonReferenceType().getCanonicalType());
  85     const char* typeString = nullptr;
  86     if( tc.Struct("StringConcat").Namespace("rtl").GlobalNamespace())
  87         typeString = "O(U)String";
  88     else
  89         return true;
  90     report( DiagnosticsEngine::Warning,
  91         check == Check::Var
  92             ? "creating a variable of type %0 will make it reference temporaries"
  93             : "returning a variable of type %0 will make it reference temporaries",
  94         decl->getLocation())
  95         << type;
  96     report( DiagnosticsEngine::Note,
  97         "use %0 instead",
  98         range.getBegin())
  99         << typeString
 100         << FixItHint::CreateReplacement( range, typeString );
 101     return true;
 102     }
 103
 104 static Plugin::Registration< StringConcatAuto > stringconcatauto( "stringconcatauto" );
 105
 106 } // namespace
 107
 108 #endif // LO_CLANG_SHARED_PLUGINS
 109
 110 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */