compilerplugins/clang/staticconstexpr.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 <cassert>
  13 #include <stack>
  14
  15 #include "check.hxx"
  16 #include "plugin.hxx"
  17 #include "config_clang.h"
  18
  19 /**
  20 In MSVC, non-static constexpr objects are initialized at run-time
  21
  22 So make sure that function-local vars are declared static.
  23
  24 */
  25 namespace
  26 {
  27 class StaticConstexpr final : public loplugin::FilteringPlugin<StaticConstexpr>
  28 {
  29 public:
  30     explicit StaticConstexpr(loplugin::InstantiationData const& data)
  31         : FilteringPlugin(data)
  32     {
  33     }
  34
  35     bool VisitVarDecl(const VarDecl* varDecl)
  36     {
  37         if (ignoreLocation(varDecl))
  38             return true;
  39         if (!varDecl->isConstexpr())
  40             return true;
  41         if (!varDecl->isLocalVarDecl())
  42             return true;
  43         if (varDecl->isStaticLocal())
  44             return true;
  45         if (auto const functionDecl = dyn_cast_or_null<FunctionDecl>(varDecl->getDeclContext()))
  46         {
  47             // cannot convert these, definition of a static variable in a constexpr function is a C++23 extension
  48             if (functionDecl->isConstexpr())
  49                 return true;
  50         }
  51         if (varDecl->getType()->isBuiltinType() || varDecl->getType()->isEnumeralType())
  52             return true;
  53         // ignore the o3tl::getConversionMulDiv stuff
  54         loplugin::TypeCheck tc(varDecl->getType());
  55         if (tc.ClassOrStruct("pair").StdNamespace())
  56             return true;
  57         if (tc.Struct("m_and_d").Namespace("detail").Namespace("o3tl"))
  58             return true;
  59         if (tc.ClassOrStruct("TypedWhichId"))
  60             return true;
  61         if (tc.ClassOrStruct("Color"))
  62             return true;
  63         report(DiagnosticsEngine::Warning,
  64                "function-local constexpr vars should be declared static", varDecl->getBeginLoc())
  65             << varDecl->getSourceRange();
  66         return true;
  67     }
  68
  69     bool preRun() override
  70     {
  71         if (!compiler.getLangOpts().CPlusPlus)
  72             return false;
  73         return true;
  74     }
  75
  76 private:
  77     void run() override
  78     {
  79         if (preRun())
  80         {
  81             TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
  82         }
  83     }
  84 };
  85
  86 loplugin::Plugin::Registration<StaticConstexpr> staticconstexpr("staticconstexpr");
  87 }
  88
  89 #endif
  90
  91 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */