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