compilerplugins/clang/store/tutorial/tutorial3.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  * Based on LLVM/Clang.
   6  *
   7  * This file is distributed under the University of Illinois Open Source
   8  * License. See LICENSE.TXT for details.
   9  *
  10  */
  11
  12 #include "tutorial3.hxx"
  13
  14 /*
  15 This is a rewriter.
  16
  17 It looks for if statements with a comparison followed by literal return false
  18 and modifies the return statements to 'return maybereturntrue;'
  19 */
  20
  21 namespace loplugin
  22 {
  23
  24 // Ctor, pass arguments.
  25 Tutorial3::Tutorial3( const InstantiationData& data )
  26     : FilteringRewritePlugin( data )
  27     {
  28     }
  29
  30 void Tutorial3::run()
  31     {
  32     TraverseDecl( compiler.getASTContext().getTranslationUnitDecl());
  33     }
  34
  35 bool Tutorial3::VisitIfStmt( const IfStmt* ifstmt )
  36     {
  37     if( ignoreLocation( ifstmt ))
  38         return true;
  39     if( const BinaryOperator* oper = dyn_cast< BinaryOperator >( ifstmt->getCond()))
  40         {
  41         if( oper->getOpcode() == BO_EQ )
  42             {
  43             // Modify the sub-statement if it is 'return false'.
  44             modifyReturnFalse( ifstmt->getThen());
  45             // Modify the sub-statement if it is '{ return false; }'.
  46             if( const CompoundStmt* compound = dyn_cast< CompoundStmt >( ifstmt->getThen()))
  47                 {
  48                 if( compound->size() == 1 ) // one statement
  49                     modifyReturnFalse( *compound->body_begin());
  50                 }
  51             }
  52         }
  53     return true;
  54     }
  55
  56 void Tutorial3::modifyReturnFalse( const Stmt* stmt )
  57     {
  58     // Is it return statement?
  59     if( const ReturnStmt* returnstmt = dyn_cast< ReturnStmt >( stmt ))
  60         {
  61         // dyn_cast_or_null<> can also be passed NULL, unlike dyn_cast<>
  62         if( const CXXBoolLiteralExpr* boolliteral = dyn_cast_or_null< CXXBoolLiteralExpr >( returnstmt->getRetValue()))
  63             {
  64             if( boolliteral->getValue() == false )
  65                 { // It is, modify the false to true using LO plugin helper function.
  66                 replaceText( boolliteral->getSourceRange(), "maybereturntrue" );
  67                 }
  68             }
  69         }
  70     }
  71
  72 // Register the plugin action with the LO plugin handling.
  73 static Plugin::Registration< Tutorial3 > tutorial3( "tutorial3" );
  74
  75 } // namespace
  76
  77 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */