compilerplugins/clang/redundantpointerops.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 #ifndef LO_CLANG_SHARED_PLUGINS
  10
  11 #include <cassert>
  12 #include <string>
  13 #include <iostream>
  14 #include <fstream>
  15 #include <set>
  16
  17 #include <clang/AST/CXXInheritance.h>
  18
  19 #include "check.hxx"
  20 #include "plugin.hxx"
  21
  22 /**
  23  * Look for:
  24  *     (&x)->y
  25  * which can be transformed to:
  26  *      x.y
  27  * And
  28  *    &*x
  29  * which can be:
  30  *    x
  31  *
  32  * @TODO
  33  *    (*x).y
  34  *  which can be:
  35  *    x->y
  36  */
  37
  38 namespace {
  39
  40 class RedundantPointerOps:
  41     public loplugin::FilteringPlugin<RedundantPointerOps>
  42 {
  43 public:
  44     explicit RedundantPointerOps(loplugin::InstantiationData const & data): FilteringPlugin(data) {}
  45
  46     virtual void run() override
  47     {
  48         if (preRun())
  49             TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
  50     }
  51
  52     bool VisitFunctionDecl(FunctionDecl const *);
  53     bool VisitMemberExpr(MemberExpr const *);
  54     bool VisitUnaryOperator(UnaryOperator const *);
  55 };
  56
  57 bool RedundantPointerOps::VisitFunctionDecl(FunctionDecl const * functionDecl)
  58 {
  59     if (ignoreLocation(functionDecl))
  60         return true;
  61 //    if (functionDecl->getIdentifier() && functionDecl->getName() == "function6b")
  62 //        functionDecl->dump();
  63     return true;
  64 }
  65
  66 bool RedundantPointerOps::VisitMemberExpr(MemberExpr const * memberExpr)
  67 {
  68     if (ignoreLocation(memberExpr))
  69         return true;
  70     if (memberExpr->getBeginLoc().isMacroID())
  71         return true;
  72     auto base = memberExpr->getBase()->IgnoreParenImpCasts();
  73             //parentStmt(parentStmt(memberExpr))->dump();
  74     if (memberExpr->isArrow())
  75     {
  76         if (auto unaryOp = dyn_cast<UnaryOperator>(base))
  77         {
  78             if (unaryOp->getOpcode() == UO_AddrOf)
  79                 report(
  80                     DiagnosticsEngine::Warning,
  81                     "'&' followed by '->' operating on %0, rather use '.'",
  82                     memberExpr->getBeginLoc())
  83                     << memberExpr->getBase()->getType()->getPointeeType()
  84                     << memberExpr->getSourceRange();
  85
  86         }
  87         else if (auto operatorCallExpr = dyn_cast<CXXOperatorCallExpr>(base))
  88         {
  89             if (operatorCallExpr->getOperator() == OO_Amp)
  90                 report(
  91                     DiagnosticsEngine::Warning,
  92                     "'&' followed by '->' operating on %0, rather use '.'",
  93                     memberExpr->getBeginLoc())
  94                     << memberExpr->getBase()->getType()->getPointeeType()
  95                     << memberExpr->getSourceRange();
  96
  97         }
  98         else if (auto cxxMemberCallExpr = dyn_cast<CXXMemberCallExpr>(base))
  99         {
 100             auto methodDecl = cxxMemberCallExpr->getMethodDecl();
 101             if (methodDecl->getIdentifier() && methodDecl->getName() == "get")
 102             {
 103                 auto const e = cxxMemberCallExpr->getImplicitObjectArgument();
 104                 if (loplugin::isSmartPointerType(e))
 105                     report(
 106                         DiagnosticsEngine::Warning,
 107                         "'get()' followed by '->' operating on %0, just use '->'",
 108                         memberExpr->getBeginLoc())
 109                         << e->IgnoreImpCasts()->getType().getLocalUnqualifiedType()
 110                         << memberExpr->getSourceRange();
 111             }
 112         }
 113     }
 114 //    else
 115 //    {
 116 //        if (auto unaryOp = dyn_cast<UnaryOperator>(base))
 117 //        {
 118 //            if (unaryOp->getOpcode() == UO_Deref)
 119 //                report(
 120 //                    DiagnosticsEngine::Warning, "'*' followed by '.', rather use '->'",
 121 //                    memberExpr->getLocStart())
 122 //                    << memberExpr->getSourceRange();
 123 //
 124 //        }
 125 //    }
 126     return true;
 127 }
 128
 129 bool RedundantPointerOps::VisitUnaryOperator(UnaryOperator const * unaryOperator)
 130 {
 131     if (ignoreLocation(unaryOperator))
 132         return true;
 133     if (unaryOperator->getBeginLoc().isMacroID())
 134         return true;
 135     if (unaryOperator->getOpcode() != UO_Deref)
 136         return true;
 137     auto subExpr = unaryOperator->getSubExpr()->IgnoreParenImpCasts();
 138     auto innerOp = dyn_cast<UnaryOperator>(subExpr);
 139     if (innerOp && innerOp->getOpcode() == UO_AddrOf)
 140         report(
 141             DiagnosticsEngine::Warning, "'&' followed by '*' operating on %0, rather use '.'",
 142             unaryOperator->getBeginLoc())
 143             << innerOp->getSubExpr()->getType() << unaryOperator->getSourceRange();
 144     if (auto cxxMemberCallExpr = dyn_cast<CXXMemberCallExpr>(subExpr))
 145     {
 146         auto methodDecl = cxxMemberCallExpr->getMethodDecl();
 147         if (methodDecl->getIdentifier() && methodDecl->getName() == "get")
 148         {
 149             auto const e = cxxMemberCallExpr->getImplicitObjectArgument();
 150             if (loplugin::isSmartPointerType(e))
 151                 report(
 152                     DiagnosticsEngine::Warning,
 153                     "'*' followed by '.get()' operating on %0, just use '*'",
 154                     unaryOperator->getBeginLoc())
 155                     << e->IgnoreImpCasts()->getType().getLocalUnqualifiedType()
 156                     << unaryOperator->getSourceRange();
 157         }
 158     }
 159     return true;
 160 }
 161
 162 loplugin::Plugin::Registration< RedundantPointerOps > redundantpointerops("redundantpointerops");
 163
 164 } // namespace
 165
 166 #endif // LO_CLANG_SHARED_PLUGINS
 167
 168 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */