compilerplugins/clang/store/changefunctioncalls.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 /*
  13 This is a rewriter.
  14
  15 Changes all calls to a specific function (after it's been renamed or its
  16 arguments have changed).
  17
  18 This specific example checks for calls to function 'void bar(unsigned int)'
  19 and adds '+ 10' to the argument (as plain text, so if the argument is a more
  20 complex expression, operator precedence may mean the result is actually different).
  21
  22 This can be easily adjusted for different modifications to a function:
  23 - replace CallExpr with CXXOperatorCallExpr or CXXMemberCallExpr
  24 - check different names or arguments
  25 - change getDirectCallee() to getCallee()
  26 - etc.
  27 */
  28
  29 #include "plugin.hxx"
  30
  31 namespace loplugin
  32 {
  33
  34 class ChangeFunctionCalls
  35     : public RecursiveASTVisitor< ChangeFunctionCalls >
  36     , public RewritePlugin
  37     {
  38     public:
  39         explicit ChangeFunctionCalls( CompilerInstance& compiler, Rewriter& rewriter );
  40         virtual void run() override;
  41         bool VisitCallExpr( const CallExpr* call );
  42     };
  43
  44 ChangeFunctionCalls::ChangeFunctionCalls( CompilerInstance& compiler, Rewriter& rewriter )
  45     : RewritePlugin( compiler, rewriter )
  46     {
  47     }
  48
  49 void ChangeFunctionCalls::run()
  50     {
  51     TraverseDecl( compiler.getASTContext().getTranslationUnitDecl());
  52     }
  53
  54 bool ChangeFunctionCalls::VisitCallExpr( const CallExpr* call )
  55     {
  56     if( ignoreLocation( call ))
  57         return true;
  58     // Using getDirectCallee() here means that we find only calls
  59     // that call the function directly (i.e. not using a pointer, for example).
  60     // Use getCallee() to include also those :
  61     //    if( const FunctionDecl* func = dyn_cast_or_null< FunctionDecl >( call->getCalleeDecl()))
  62     if( const FunctionDecl* func = call->getDirectCallee())
  63         {
  64         // Optimize, getQualifiedNameAsString() is reportedly expensive,
  65         // so first check fast details like number of arguments or the (unqualified)
  66         // name before checking the fully qualified name.
  67         // See FunctionDecl for all the API about the function.
  68         if( func->getNumParams() == 1 && func->getIdentifier() != NULL
  69             && ( func->getName() == "bar" ))
  70             {
  71             string qualifiedName = func->getQualifiedNameAsString();
  72             if( qualifiedName == "bar" )
  73                 {
  74                 // Further checks about arguments. Check mainly ParmVarDecl, VarDecl,
  75                 // ValueDecl and QualType for Clang API details.
  76                 string arg0 = func->getParamDecl( 0 )->getType().getAsString();
  77                 if( arg0 == "unsigned int" )
  78                     {
  79                     insertTextAfterToken( call->getArg( 0 )->getLocEnd(), " + 10" );
  80                     report( DiagnosticsEngine::Warning, "found", call->getLocStart());
  81                     }
  82                 }
  83             }
  84         }
  85     return true;
  86     }
  87
  88 static Plugin::Registration< ChangeFunctionCalls > X( "changefunctioncalls" );
  89
  90 } // namespace
  91
  92 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */