compilerplugins/clang/charrightshift.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 "check.hxx"
  13 #include "plugin.hxx"
  14
  15 namespace {
  16
  17 class CharRightShift:
  18     public loplugin::FilteringPlugin<CharRightShift>
  19 {
  20 public:
  21     explicit CharRightShift(loplugin::InstantiationData const & data):
  22         FilteringPlugin(data) {}
  23
  24     void run() override
  25     { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
  26
  27     bool VisitBinaryOperator(BinaryOperator const * expr) {
  28         if (expr->getOpcode() != BO_Shr) {
  29             return true;
  30         }
  31         if (ignoreLocation(expr)) {
  32             return true;
  33         }
  34         auto t = expr->getLHS()->IgnoreParenImpCasts()->getType();
  35         if (!loplugin::TypeCheck(t).Char()) {
  36             return true;
  37         }
  38         if (!expr->getRHS()->getType()->isBuiltinType()) {
  39             //TODO: in which case the expression should be an
  40             // CXXOperatorCallExpr instead of a BinaryOperator? but at least
  41             // recent Clang trunk reports
  42             //
  43             //  '(' >> orExpression
  44             //
  45             // (connectivity/source/commontools/RowFunctionParser.cxx, the RHS
  46             // being of type boost::spirit::rule<ScannerT>) here
  47             return true;
  48         }
  49         report(
  50             DiagnosticsEngine::Warning,
  51             ("right shift of %0 is implementation-defined when 'char' is signed"
  52              " and value is negative"),
  53             expr->getLHS()->getExprLoc())
  54             << t << expr->getSourceRange();
  55         return true;
  56     }
  57 };
  58
  59 loplugin::Plugin::Registration<CharRightShift> charrightshift("charrightshift");
  60
  61 }
  62
  63 #endif // LO_CLANG_SHARED_PLUGINS
  64
  65 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */