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