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 #ifndef LO_CLANG_SHARED_PLUGINS
  11
  12 #include <vector>
  13
  14 #include "plugin.hxx"
  15
  16 // Warn when a variable is referenced from its own initializer.  This is not invalid in general (see
  17 // C++17 [basic.life]), but is at least suspicious.
  18
  19 namespace
  20 {
  21 class SelfInit : public loplugin::FilteringPlugin<SelfInit>
  22 {
  23 public:
  24     explicit SelfInit(loplugin::InstantiationData const& data)
  25         : FilteringPlugin(data)
  26     {
  27     }
  28
  29     bool PreTraverseVarDecl(VarDecl* decl)
  30     {
  31         decls_.push_back({ decl, decl->getCanonicalDecl() });
  32         return true;
  33     }
  34     bool PostTraverseVarDecl(VarDecl*, bool)
  35     {
  36         decls_.pop_back();
  37         return true;
  38     }
  39     bool TraverseVarDecl(VarDecl* decl)
  40     {
  41         PreTraverseVarDecl(decl);
  42         auto const ret = FilteringPlugin::TraverseVarDecl(decl);
  43         PostTraverseVarDecl(decl, ret);
  44         return ret;
  45     }
  46
  47     bool PreTraverseUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr* expr)
  48     {
  49         if (expr->getKind() == UETT_SizeOf)
  50             return false;
  51         return true;
  52     }
  53     bool TraverseUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr* expr)
  54     {
  55         if (PreTraverseUnaryExprOrTypeTraitExpr(expr))
  56             return FilteringPlugin::TraverseUnaryExprOrTypeTraitExpr(expr);
  57         return true;
  58     }
  59
  60     bool TraverseCXXTypeidExpr(CXXTypeidExpr*) { return true; }
  61     bool PreTraverseCXXTypeidExpr(CXXTypeidExpr*) { return false; }
  62
  63     bool TraverseCXXNoexceptExpr(CXXNoexceptExpr*) { return true; }
  64     bool PreTraverseCXXNoexceptExpr(CXXNoexceptExpr*) { return false; }
  65
  66     bool TraverseDecltypeTypeLoc(DecltypeTypeLoc) { return true; }
  67     bool PreTraverseDecltypeTypeLoc(DecltypeTypeLoc) { return false; }
  68
  69     bool VisitDeclRefExpr(DeclRefExpr const* expr)
  70     {
  71         if (ignoreLocation(expr))
  72         {
  73             return true;
  74         }
  75         for (auto const& i : decls_)
  76         {
  77             if (expr->getDecl()->getCanonicalDecl() == i.canonical)
  78             {
  79                 report(
  80                     DiagnosticsEngine::Warning,
  81                     ("referencing a variable during its own initialization is error-prone and thus"
  82                      " suspicious"),
  83                     expr->getLocation())
  84                     << expr->getSourceRange();
  85                 report(DiagnosticsEngine::Note, "variable declared here", i.current->getLocation())
  86                     << i.current->getSourceRange();
  87             }
  88         }
  89         return true;
  90     }
  91
  92 private:
  93     void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
  94
  95     struct Decl
  96     {
  97         VarDecl const* current;
  98         VarDecl const* canonical;
  99     };
 100
 101     std::vector<Decl> decls_;
 102 };
 103
 104 loplugin::Plugin::Registration<SelfInit> selfinit("selfinit");
 105 }
 106
 107 #endif // LO_CLANG_SHARED_PLUGINS
 108
 109 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */