compilerplugins/clang/trivialdestructor.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 <string>
  12 #include <iostream>
  13 #include <unordered_map>
  14 #include <unordered_set>
  15
  16 #include "plugin.hxx"
  17 #include "check.hxx"
  18 #include "config_clang.h"
  19 #include "clang/AST/CXXInheritance.h"
  20 #include "clang/AST/StmtVisitor.h"
  21
  22 // Look for explicit destructors that can be trivial (and therefore don't need to be declared)
  23
  24 namespace
  25 {
  26 class TrivialDestructor : public loplugin::FilteringPlugin<TrivialDestructor>
  27 {
  28 public:
  29     explicit TrivialDestructor(loplugin::InstantiationData const& data)
  30         : FilteringPlugin(data)
  31     {
  32     }
  33
  34     virtual void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
  35
  36     bool VisitCXXDestructorDecl(CXXDestructorDecl const*);
  37
  38 private:
  39     bool HasTrivialDestructorBody(const CXXRecordDecl* ClassDecl);
  40     bool FieldHasTrivialDestructor(const FieldDecl* Field);
  41 };
  42
  43 bool TrivialDestructor::VisitCXXDestructorDecl(CXXDestructorDecl const* destructorDecl)
  44 {
  45     if (ignoreLocation(destructorDecl))
  46         return true;
  47     if (!destructorDecl->isThisDeclarationADefinition())
  48         return true;
  49     if (!destructorDecl->hasTrivialBody())
  50         return true;
  51     if (destructorDecl->isVirtual())
  52         return true;
  53     if (destructorDecl->getExceptionSpecType() != EST_None)
  54         return true;
  55     if (destructorDecl->getAccess() != AS_public)
  56         return true;
  57     if (isInUnoIncludeFile(
  58             compiler.getSourceManager().getSpellingLoc(destructorDecl->getLocation())))
  59         return true;
  60     if (!HasTrivialDestructorBody(destructorDecl->getParent()))
  61         return true;
  62
  63     report(DiagnosticsEngine::Warning, "no need for explicit destructor decl",
  64            destructorDecl->getLocation())
  65         << destructorDecl->getSourceRange();
  66     for (FunctionDecl const* d2 = destructorDecl;;)
  67     {
  68         d2 = d2->getPreviousDecl();
  69         if (d2 == nullptr)
  70         {
  71             break;
  72         }
  73         report(DiagnosticsEngine::Note, "previous declaration is here", d2->getLocation())
  74             << d2->getSourceRange();
  75     }
  76     return true;
  77 }
  78
  79 bool TrivialDestructor::HasTrivialDestructorBody(const CXXRecordDecl* ClassDecl)
  80 {
  81     // Check fields.
  82     for (const auto* field : ClassDecl->fields())
  83         if (!FieldHasTrivialDestructor(field))
  84             return false;
  85
  86     // Check bases.
  87     for (const auto& I : ClassDecl->bases())
  88     {
  89         const CXXRecordDecl* Base = I.getType()->getAsCXXRecordDecl();
  90         if (!Base->hasTrivialDestructor())
  91             return false;
  92     }
  93
  94     return true;
  95 }
  96
  97 bool TrivialDestructor::FieldHasTrivialDestructor(const FieldDecl* Field)
  98 {
  99     QualType FieldBaseElementType = compiler.getASTContext().getBaseElementType(Field->getType());
 100
 101     const RecordType* RT = FieldBaseElementType->getAs<RecordType>();
 102     if (!RT)
 103         return true;
 104
 105     CXXRecordDecl* FieldClassDecl = cast<CXXRecordDecl>(RT->getDecl());
 106
 107     return FieldClassDecl->hasTrivialDestructor();
 108 }
 109
 110 loplugin::Plugin::Registration<TrivialDestructor> X("trivialdestructor", true);
 111 }
 112
 113 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */