compilerplugins/clang/unicodetochar.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 <stack>
  11
  12 #include "check.hxx"
  13 #include "plugin.hxx"
  14
  15 // In C++, find implicit conversions from char16_t (aka sal_Unicode) to char.
  16 // Such places are probably meant to properly work on char16_t instead.
  17
  18 namespace {
  19
  20 class UnicodeToChar final:
  21     public loplugin::FilteringPlugin<UnicodeToChar>
  22 {
  23 public:
  24     explicit UnicodeToChar(loplugin::InstantiationData const & data):
  25         FilteringPlugin(data) {}
  26
  27     bool TraverseCStyleCastExpr(CStyleCastExpr * expr) {
  28         subExprs_.push(expr->getSubExpr());
  29         bool ret = RecursiveASTVisitor::TraverseCStyleCastExpr(expr);
  30         subExprs_.pop();
  31         return ret;
  32     }
  33
  34     bool TraverseCXXStaticCastExpr(CXXStaticCastExpr * expr) {
  35         subExprs_.push(expr->getSubExpr());
  36         bool ret = RecursiveASTVisitor::TraverseCXXStaticCastExpr(expr);
  37         subExprs_.pop();
  38         return ret;
  39     }
  40
  41     bool TraverseCXXFunctionalCastExpr(CXXFunctionalCastExpr * expr) {
  42         subExprs_.push(expr->getSubExpr());
  43         bool ret = RecursiveASTVisitor::TraverseCXXFunctionalCastExpr(expr);
  44         subExprs_.pop();
  45         return ret;
  46     }
  47
  48     bool VisitImplicitCastExpr(ImplicitCastExpr const * expr) {
  49         if ((!subExprs_.empty() && expr == subExprs_.top())
  50             || ignoreLocation(expr))
  51         {
  52             return true;
  53         }
  54         if (!(loplugin::TypeCheck(expr->getType()).Char()
  55               && expr->getSubExpr()->getType()->isSpecificBuiltinType(
  56                   clang::BuiltinType::Char16)))
  57         {
  58             return true;
  59         }
  60         APSInt res;
  61         if (compat::EvaluateAsInt(expr->getSubExpr(), res, compiler.getASTContext())
  62             && res >= 0 && res <= 0x7F)
  63         {
  64             return true;
  65         }
  66         report(
  67             DiagnosticsEngine::Warning,
  68             "suspicious implicit cast from %0 to %1",
  69             expr->getExprLoc())
  70             << expr->getSubExpr()->getType() << expr->getType()
  71             << expr->getSourceRange();
  72         return true;
  73     }
  74
  75 private:
  76     void run() override {
  77         if (compiler.getLangOpts().CPlusPlus) {
  78             TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
  79         }
  80     }
  81
  82     std::stack<Expr const *> subExprs_;
  83 };
  84
  85 static loplugin::Plugin::Registration<UnicodeToChar> reg("unicodetochar");
  86
  87 }
  88
  89 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */