compilerplugins/clang/getstr.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 #ifndef LO_CLANG_SHARED_PLUGINS
  11
  12 #include <cassert>
  13 #include <stack>
  14
  15 #include "check.hxx"
  16 #include "compat.hxx"
  17 #include "plugin.hxx"
  18
  19 // Find matches of
  20 //
  21 //   ... << s.getStr()
  22 //
  23 // (for the rtl string classes) that can be written as just
  24 //
  25 //   ... << s
  26
  27 namespace
  28 {
  29 class GetStr final : public loplugin::FilteringPlugin<GetStr>
  30 {
  31 public:
  32     explicit GetStr(loplugin::InstantiationData const& data)
  33         : FilteringPlugin(data)
  34     {
  35     }
  36
  37     bool PreTraverseFunctionDecl(FunctionDecl* decl)
  38     {
  39         functions_.push(decl);
  40         return true;
  41     }
  42
  43     bool PostTraverseFunctionDecl(FunctionDecl*, bool)
  44     {
  45         assert(!functions_.empty());
  46         functions_.pop();
  47         return true;
  48     }
  49
  50     bool TraverseFunctionDecl(FunctionDecl* decl)
  51     {
  52         bool ret = true;
  53         if (PreTraverseFunctionDecl(decl))
  54         {
  55             ret = FilteringPlugin::TraverseFunctionDecl(decl);
  56             PostTraverseFunctionDecl(decl, ret);
  57         }
  58         return ret;
  59     }
  60
  61     bool VisitCXXOperatorCallExpr(CXXOperatorCallExpr* expr)
  62     {
  63         if (ignoreLocation(expr))
  64         {
  65             return true;
  66         }
  67         if (expr->getOperator() != OO_LessLess)
  68         {
  69             return true;
  70         }
  71         assert(expr->getNumArgs() == 2);
  72         if (!loplugin::TypeCheck(expr->getArg(0)->getType())
  73                  .ClassOrStruct("basic_ostream")
  74                  .StdNamespace()) //TODO: check template args
  75         {
  76             return true;
  77         }
  78         auto const arg1 = expr->getArg(1);
  79         auto const e = dyn_cast<CXXMemberCallExpr>(arg1->IgnoreParenImpCasts());
  80         if (e == nullptr)
  81         {
  82             return true;
  83         }
  84         bool castToVoid = false;
  85         if (auto const ic = dyn_cast<ImplicitCastExpr>(arg1))
  86         {
  87             if (loplugin::TypeCheck(arg1->getType()).Pointer().Void())
  88             {
  89                 castToVoid = true;
  90             }
  91         }
  92         auto const t = compat::getObjectType(e);
  93         auto const tc = loplugin::TypeCheck(t);
  94         if (!(tc.Class("OString").Namespace("rtl").GlobalNamespace()
  95               || tc.Class("OUString").Namespace("rtl").GlobalNamespace()
  96               || (castToVoid
  97                   && (tc.Class("OStringBuffer").Namespace("rtl").GlobalNamespace()
  98                       || tc.Class("OUStringBuffer").Namespace("rtl").GlobalNamespace()))))
  99         {
 100             return true;
 101         }
 102         if (!loplugin::DeclCheck(e->getMethodDecl()).Function("getStr"))
 103         {
 104             return true;
 105         }
 106         if (castToVoid)
 107         {
 108             report(DiagnosticsEngine::Warning,
 109                    ("suspicious use of 'getStr' on an object of type %0; the result is implicitly"
 110                     " cast to a void pointer in a call of 'operator <<'"),
 111                    e->getExprLoc())
 112                 << t.getLocalUnqualifiedType() << expr->getSourceRange();
 113             return true;
 114         }
 115         if (!functions_.empty())
 116         {
 117             // Filter out occurrences of `s << t.getStr()` in the implementation of
 118             // `operator <<(std::basic_ostream<...> & s, T const & t)`:
 119             auto const fd = functions_.top();
 120             if (fd->getOverloadedOperator() == OO_LessLess)
 121             {
 122                 assert(fd->getNumParams() == 2);
 123                 if (loplugin::TypeCheck(fd->getParamDecl(0)->getType())
 124                         .LvalueReference()
 125                         .NonConstVolatile()
 126                         .TemplateSpecializationClass()
 127                         .ClassOrStruct("basic_ostream")
 128                         .StdNamespace()) //TODO: check template args
 129                 {
 130                     if (auto const t2
 131                         = fd->getParamDecl(1)->getType()->getAs<LValueReferenceType>())
 132                     {
 133                         auto const t3 = t2->getPointeeType();
 134                         if (t3.isConstQualified() && !t3.isVolatileQualified()
 135                             && (t3.getCanonicalType().getTypePtr()
 136                                 == t.getCanonicalType().getTypePtr()))
 137                         {
 138                             return true;
 139                         }
 140                     }
 141                 }
 142             }
 143         }
 144         report(DiagnosticsEngine::Warning,
 145                ("directly use object of type %0 in a call of 'operator <<', instead of calling"
 146                 " 'getStr' first"),
 147                e->getExprLoc())
 148             << t.getLocalUnqualifiedType() << expr->getSourceRange();
 149         return true;
 150     }
 151
 152     bool preRun() override { return compiler.getLangOpts().CPlusPlus; }
 153
 154 private:
 155     std::stack<FunctionDecl*> functions_;
 156
 157     void run() override
 158     {
 159         if (preRun())
 160         {
 161             TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
 162         }
 163     }
 164 };
 165
 166 loplugin::Plugin::Registration<GetStr> getstr("getstr");
 167 }
 168
 169 #endif
 170
 171 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */