compilerplugins/clang/simplifydynamiccast.cxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   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 <cassert>
  11 #include <string>
  12 #include <iostream>
  13 #include <fstream>
  14 #include <set>
  15
  16 #include <clang/AST/CXXInheritance.h>
  17 #include "compat.hxx"
  18 #include "plugin.hxx"
  19
  20 namespace
  21 {
  22 class SimplifyDynamicCast : public loplugin::FilteringPlugin<SimplifyDynamicCast>
  23 {
  24 public:
  25     explicit SimplifyDynamicCast(loplugin::InstantiationData const& data)
  26         : FilteringPlugin(data)
  27     {
  28     }
  29
  30     virtual void run() override
  31     {
  32         //        StringRef fn(handler.getMainFileName());
  33         //        if (loplugin::isSamePathname(fn, WORKDIR "/YaccTarget/unoidl/source/sourceprovider-parser.cxx"))
  34         //             return;
  35
  36         TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
  37     }
  38
  39     bool TraverseIfStmt(IfStmt*);
  40     bool VisitCXXStaticCastExpr(CXXStaticCastExpr const*);
  41
  42 private:
  43     std::vector<QualType> dynamicCastVec;
  44     std::vector<Decl const*> dynamicCastSubExprVec;
  45     std::vector<IfStmt const*> ifVec;
  46 };
  47
  48 bool SimplifyDynamicCast::TraverseIfStmt(IfStmt* ifStmt)
  49 {
  50     auto condExpr = ifStmt->getCond()->IgnoreParenImpCasts();
  51     auto dynamicCastExpr = dyn_cast<CXXDynamicCastExpr>(condExpr);
  52     if (!dynamicCastExpr)
  53     {
  54         if (auto binaryOp = dyn_cast<BinaryOperator>(condExpr))
  55         {
  56             if (binaryOp->getOpcode() == BO_NE)
  57                 dynamicCastExpr
  58                     = dyn_cast<CXXDynamicCastExpr>(binaryOp->getLHS()->IgnoreParenImpCasts());
  59         }
  60     }
  61     Decl const* subExprDecl = nullptr;
  62     if (dynamicCastExpr)
  63     {
  64         auto subExprDeclRefExpr
  65             = dyn_cast<DeclRefExpr>(dynamicCastExpr->getSubExpr()->IgnoreParenImpCasts());
  66         if (!subExprDeclRefExpr)
  67             dynamicCastExpr = nullptr;
  68         else
  69             subExprDecl = subExprDeclRefExpr->getDecl();
  70     }
  71     if (dynamicCastExpr)
  72     {
  73         auto qt = dynamicCastExpr->getTypeAsWritten();
  74         dynamicCastVec.push_back(qt);
  75         dynamicCastSubExprVec.push_back(subExprDecl);
  76         ifVec.push_back(ifStmt);
  77     }
  78     bool ret = RecursiveASTVisitor::TraverseIfStmt(ifStmt);
  79     if (dynamicCastExpr)
  80     {
  81         dynamicCastVec.pop_back();
  82         dynamicCastSubExprVec.pop_back();
  83         ifVec.pop_back();
  84     }
  85     return ret;
  86 }
  87
  88 bool SimplifyDynamicCast::VisitCXXStaticCastExpr(CXXStaticCastExpr const* staticCastExpr)
  89 {
  90     if (ignoreLocation(staticCastExpr))
  91         return true;
  92     if (dynamicCastVec.empty())
  93         return true;
  94
  95     auto qt = staticCastExpr->getTypeAsWritten();
  96     auto it = std::find(dynamicCastVec.begin(), dynamicCastVec.end(), qt);
  97     if (it == dynamicCastVec.end())
  98         return true;
  99     int idx = it - dynamicCastVec.begin();
 100     auto subExprDecl = dyn_cast<DeclRefExpr>(staticCastExpr->getSubExpr()->IgnoreParenImpCasts());
 101     if (!subExprDecl)
 102         return true;
 103     if (dynamicCastSubExprVec[idx] != subExprDecl->getDecl())
 104         return true;
 105     report(DiagnosticsEngine::Warning, "simplify, use var in if",
 106            compat::getBeginLoc(staticCastExpr))
 107         << staticCastExpr->getSourceRange();
 108     auto ifStmt = ifVec[idx];
 109     report(DiagnosticsEngine::Note, "if here", compat::getBeginLoc(ifStmt))
 110         << ifStmt->getSourceRange();
 111     return true;
 112 }
 113
 114 loplugin::Plugin::Registration<SimplifyDynamicCast> X("simplifydynamiccast", true);
 115 }
 116
 117 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */