compilerplugins/clang/store/tutorial/tutorial1.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 "tutorial1.hxx"
  13
  14 /*
  15 This is a compile check.
  16
  17 Checks all return statements and warns if they return literal false (i.e. 'return false').
  18 */
  19
  20 namespace loplugin
  21 {
  22
  23 // Ctor, nothing special, pass the argument(s).
  24 Tutorial1::Tutorial1( const InstantiationData& data )
  25     : FilteringPlugin( data )
  26     {
  27     }
  28
  29 // Perform the actual action.
  30 void Tutorial1::run()
  31     {
  32     // Traverse the whole AST of the translation unit (i.e. examine the whole source file).
  33     // The Clang AST helper class will call VisitReturnStmt for every return statement.
  34     TraverseDecl( compiler.getASTContext().getTranslationUnitDecl());
  35     }
  36
  37 // This function is called for every return statement.
  38 // Returning true means to continue with examining the AST, false means to stop (just always return true).
  39 bool Tutorial1::VisitReturnStmt( const ReturnStmt* returnstmt )
  40     {
  41     // Helper function from the LO base plugin class, call at the very beginning to ignore sources
  42     // that should not be processed (e.g. system headers).
  43     if( ignoreLocation( returnstmt ))
  44         return true;
  45     // Get the expression in the return statement (see ReturnStmt API docs).
  46     const Expr* expression = returnstmt->getRetValue();
  47     if( expression == NULL )
  48         return true; // plain 'return;' without expression
  49     // Check if the expression is a bool literal (Clang uses dyn_cast<> instead of dynamic_cast<>).
  50     if( const CXXBoolLiteralExpr* boolliteral = dyn_cast< CXXBoolLiteralExpr >( expression ))
  51         { // It is.
  52         if( boolliteral->getValue() == false ) // Is it 'return false;' ? (See CXXBoolLiteralExpr API docs)
  53             { // Ok, warn, use LO plugin helper function.
  54             report( DiagnosticsEngine::Warning, // It's just a warning.
  55                 "returning false",  // the message
  56                 boolliteral->getLocStart()) // and the exact position where the message should point
  57                     << returnstmt->getSourceRange(); // and the full return statement to highlight (optional)
  58             }
  59         }
  60     return true;
  61     }
  62
  63 // Register the plugin action with the LO plugin handling.
  64 static Plugin::Registration< Tutorial1 > tutorial1( "tutorial1" );
  65
  66 } // namespace
  67
  68 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */