compilerplugins/clang/finalclasses.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  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  */
   9
  10 #include <cassert>
  11 #include <set>
  12 #include <string>
  13 #include <iostream>
  14 #include "config_clang.h"
  15 #include "plugin.hxx"
  16 #include <fstream>
  17
  18 /**
  19 Look for classes that are final i.e. nothing extends them, and have either
  20 (a) protected fields or members.
  21 or
  22 (b) virtual members
  23
  24 In the case of (a), those members/fields can be made private.
  25 In the case of (b), making the class final means the compiler can devirtualise
  26 some method calls
  27
  28 The process goes something like this:
  29   $ make check
  30   $ make FORCE_COMPILE=all COMPILER_PLUGIN_TOOL='finalclasses' check
  31   $ ./compilerplugins/clang/finalclasses.py
  32
  33 */
  34
  35 namespace {
  36
  37 // try to limit the voluminous output a little
  38 static std::set<std::string> inheritedFromSet;
  39 static std::map<std::string,std::string> definitionMap;  // className -> filename
  40
  41 class FinalClasses:
  42     public RecursiveASTVisitor<FinalClasses>, public loplugin::Plugin
  43 {
  44 public:
  45     explicit FinalClasses(loplugin::InstantiationData const & data):
  46         Plugin(data) {}
  47
  48     virtual void run() override
  49     {
  50         handler.enableTreeWideAnalysisMode();
  51
  52         TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
  53
  54         // dump all our output in one write call - this is to try and limit IO "crosstalk" between multiple processes
  55         // writing to the same logfile
  56         std::string output;
  57         for (const std::string & s : inheritedFromSet)
  58             output += "inherited-from:\t" + s + "\n";
  59         for (const auto & s : definitionMap)
  60             output += "definition:\t" + s.first + "\t" + s.second + "\n";
  61         std::ofstream myfile;
  62         myfile.open( WORKDIR "/loplugin.finalclasses.log", std::ios::app | std::ios::out);
  63         myfile << output;
  64         myfile.close();
  65     }
  66
  67     bool shouldVisitTemplateInstantiations () const { return true; }
  68
  69     bool shouldVisitImplicitCode() const { return true; }
  70
  71     bool VisitCXXRecordDecl( const CXXRecordDecl* decl);
  72 private:
  73     void checkBase(QualType qt);
  74 };
  75
  76 bool ignoreClass(StringRef s)
  77 {
  78     // ignore stuff in the standard library, and UNO stuff we can't touch.
  79     if (s.startswith("rtl::") || s.startswith("sal::") || s.startswith("com::sun::")
  80         || s.startswith("std::") || s.startswith("boost::")
  81         || s == "OString" || s == "OUString" || s == "bad_alloc")
  82     {
  83         return true;
  84     }
  85     return false;
  86 }
  87
  88 bool FinalClasses::VisitCXXRecordDecl(const CXXRecordDecl* decl)
  89 {
  90     if (ignoreLocation(decl))
  91         return true;
  92     if (!decl->hasDefinition())
  93         return true;
  94
  95     for (auto it = decl->bases_begin(); it != decl->bases_end(); ++it)
  96     {
  97         const CXXBaseSpecifier spec = *it;
  98         checkBase(spec.getType());
  99     }
 100     for (auto it = decl->vbases_begin(); it != decl->vbases_end(); ++it)
 101     {
 102         const CXXBaseSpecifier spec = *it;
 103         checkBase(spec.getType());
 104     }
 105
 106     if (decl->hasAttr<FinalAttr>())
 107         return true;
 108     bool bFoundVirtual = false;
 109     bool bFoundProtected = false;
 110     for (auto it = decl->method_begin(); it != decl->method_end(); ++it) {
 111         auto i = *it;
 112         // ignore methods that are overriding base-class methods, making them private
 113         // isn't useful
 114         if ( !i->hasAttr<OverrideAttr>() && i->getAccess() == AS_protected )
 115             bFoundProtected = true;
 116         if ( i->isVirtual() )
 117             bFoundVirtual = true;
 118     }
 119
 120     if (!bFoundProtected)
 121     {
 122         for (auto it = decl->field_begin(); it != decl->field_end(); ++it) {
 123             auto i = *it;
 124             if ( i->getAccess() == AS_protected ) {
 125                 bFoundProtected = true;
 126                 break;
 127             }
 128         }
 129     }
 130     if (!bFoundProtected && !bFoundVirtual)
 131         return true;
 132
 133     std::string s = decl->getQualifiedNameAsString();
 134     if (ignoreClass(s))
 135         return true;
 136
 137     SourceLocation spellingLocation = compiler.getSourceManager().getSpellingLoc(decl->getBeginLoc());
 138     auto const filename = getFilenameOfLocation(spellingLocation);
 139     auto sourceLocation = filename.substr(strlen(SRCDIR)).str() + ":"
 140         + std::to_string(compiler.getSourceManager().getSpellingLineNumber(spellingLocation));
 141     definitionMap.insert( std::pair<std::string,std::string>(s, sourceLocation) );
 142     return true;
 143 }
 144
 145 void FinalClasses::checkBase(QualType baseType)
 146 {
 147     // need to look through typedefs, hence the getUnqualifiedDesugaredType
 148     baseType = baseType.getDesugaredType(compiler.getASTContext());
 149     std::string x;
 150     // so that we get just the template name, excluding the template parameters
 151     if (baseType->isRecordType())
 152         x = baseType->getAsCXXRecordDecl()->getQualifiedNameAsString();
 153     else if (auto templateType = baseType->getAs<TemplateSpecializationType>())
 154         x = templateType->getTemplateName().getAsTemplateDecl()->getQualifiedNameAsString();
 155     else
 156         x = baseType.getAsString();
 157     inheritedFromSet.insert( x );
 158 }
 159
 160 loplugin::Plugin::Registration< FinalClasses > X("finalclasses", false);
 161
 162 }
 163
 164 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */