compilerplugins/clang/selfinit.cxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
   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 <vector>
  11
  12 #include "plugin.hxx"
  13
  14 // Warn when a variable is referenced from its own initializer.  This is not invalid in general (see
  15 // C++17 [basic.life]), but is at least suspicious.
  16
  17 namespace
  18 {
  19 class SelfInit : public loplugin::FilteringPlugin<SelfInit>
  20 {
  21 public:
  22     explicit SelfInit(loplugin::InstantiationData const& data)
  23         : FilteringPlugin(data)
  24     {
  25     }
  26
  27     bool TraverseVarDecl(VarDecl* decl)
  28     {
  29         decls_.push_back({ decl, decl->getCanonicalDecl() });
  30         auto const ret = FilteringPlugin::TraverseVarDecl(decl);
  31         decls_.pop_back();
  32         return ret;
  33     }
  34
  35     bool TraverseUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr* expr)
  36     {
  37         if (expr->getKind() == UETT_SizeOf)
  38         {
  39             return true;
  40         }
  41         return FilteringPlugin::TraverseUnaryExprOrTypeTraitExpr(expr);
  42     }
  43
  44     bool TraverseCXXTypeidExpr(CXXTypeidExpr const*) { return true; }
  45
  46     bool TraverseCXXNoexceptExpr(CXXNoexceptExpr const*) { return true; }
  47
  48     bool TraverseDecltypeTypeLoc(DecltypeTypeLoc) { return true; }
  49
  50     bool VisitDeclRefExpr(DeclRefExpr const* expr)
  51     {
  52         if (ignoreLocation(expr))
  53         {
  54             return true;
  55         }
  56         for (auto const& i : decls_)
  57         {
  58             if (expr->getDecl()->getCanonicalDecl() == i.canonical)
  59             {
  60                 report(
  61                     DiagnosticsEngine::Warning,
  62                     ("referencing a variable during its own initialization is error-prone and thus"
  63                      " suspicious"),
  64                     expr->getLocation())
  65                     << expr->getSourceRange();
  66                 report(DiagnosticsEngine::Note, "variable declared here", i.current->getLocation())
  67                     << i.current->getSourceRange();
  68             }
  69         }
  70         return true;
  71     }
  72
  73 private:
  74     void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
  75
  76     struct Decl
  77     {
  78         VarDecl const* current;
  79         VarDecl const* canonical;
  80     };
  81
  82     std::vector<Decl> decls_;
  83 };
  84
  85 loplugin::Plugin::Registration<SelfInit> X("selfinit");
  86 }
  87
  88 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */