compilerplugins/clang/subtlezeroinit.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 "plugin.hxx"
  11
  12 // Find occurrences of 'new T()' where the instance is zero-initialized upfront
  13 // since C++11.  For one, in many cases this may be unnecessary and unintended,
  14 // as the code was written before C++11.  For another, the zero-initialization
  15 // would go away when T gets a user-provided default constructor, for example,
  16 // so better make any necessary initialization more explicit in the code.
  17
  18 namespace {
  19
  20 class SubtleZeroInit final:
  21     public RecursiveASTVisitor<SubtleZeroInit>, public loplugin::Plugin
  22 {
  23 public:
  24     explicit SubtleZeroInit(loplugin::InstantiationData const & data):
  25         Plugin(data) {}
  26
  27     bool VisitCXXNewExpr(CXXNewExpr const * expr) {
  28         if (ignoreLocation(expr)) {
  29             return true;
  30         }
  31         auto ce = expr->getConstructExpr();
  32         if (ce == nullptr) {
  33             return true;
  34         }
  35         if (!ce->requiresZeroInitialization()) {
  36             return true;
  37         }
  38         report(
  39             DiagnosticsEngine::Warning,
  40             ("if zero-initialization of %0 is intentional here, better make"
  41              " that more explicit (e.g., assigning to members, default"
  42              " constructor, default member initializers, std::memset)"),
  43             expr->getExprLoc())
  44             << ce->getType() << expr->getSourceRange();
  45         return true;
  46     }
  47
  48 private:
  49     void run() override {
  50         if (compiler.getLangOpts().CPlusPlus) {
  51             TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
  52         }
  53     }
  54 };
  55
  56 static loplugin::Plugin::Registration<SubtleZeroInit> reg("subtlezeroinit");
  57
  58 }
  59
  60 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */