compilerplugins/clang/readability-redundant-pp.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 <iostream>
  13 #include <stack>
  14
  15 #include "plugin.hxx"
  16
  17 #include <clang/Frontend/CompilerInstance.h>
  18 #include <clang/Frontend/FrontendActions.h>
  19 #include <clang/Tooling/CommonOptionsParser.h>
  20 #include <clang/Tooling/Refactoring.h>
  21 #include <llvm/Support/Signals.h>
  22
  23 /// Finds preprocessor usage which is redundant (only #ifndef for now).
  24
  25 namespace loplugin
  26 {
  27 struct Entry
  28 {
  29     clang::SourceLocation m_aLoc;
  30     std::string m_aMacroName;
  31 };
  32
  33 class RedundantPreprocessor : public clang::PPCallbacks, public Plugin
  34 {
  35 public:
  36     explicit RedundantPreprocessor(const InstantiationData& data);
  37     virtual void run() override;
  38     void Ifndef(clang::SourceLocation aLoc, const clang::Token& rMacroNameTok,
  39                 const clang::MacroDefinition& rMacroDefinition) override;
  40     void Ifdef(clang::SourceLocation aLoc, const clang::Token& rMacroNameTok,
  41                const clang::MacroDefinition& rMacroDefinition) override;
  42     void Endif(clang::SourceLocation aLoc, clang::SourceLocation aIfLoc) override;
  43     enum
  44     {
  45         isPPCallback = true
  46     };
  47
  48 private:
  49     clang::Preprocessor& m_rPP;
  50     std::vector<Entry> m_aDefStack;
  51     std::vector<Entry> m_aNotDefStack;
  52 };
  53
  54 RedundantPreprocessor::RedundantPreprocessor(const InstantiationData& data)
  55     : Plugin(data)
  56     , m_rPP(compiler.getPreprocessor())
  57 {
  58     compiler.getPreprocessor().addPPCallbacks(std::unique_ptr<PPCallbacks>(this));
  59 }
  60
  61 void RedundantPreprocessor::run()
  62 {
  63     // nothing, only check preprocessor usage
  64 }
  65
  66 void RedundantPreprocessor::Ifdef(clang::SourceLocation aLoc, const clang::Token& rMacroNameTok,
  67                                   const clang::MacroDefinition& /*rMacroDefinition*/)
  68 {
  69     if (ignoreLocation(aLoc))
  70         return;
  71
  72     if (m_rPP.getSourceManager().isInMainFile(aLoc))
  73     {
  74         std::string aMacroName = m_rPP.getSpelling(rMacroNameTok);
  75         for (const auto& rEntry : m_aDefStack)
  76         {
  77             if (rEntry.m_aMacroName == aMacroName)
  78             {
  79                 report(DiagnosticsEngine::Warning, "nested ifdef", aLoc);
  80                 report(DiagnosticsEngine::Note, "previous ifdef", rEntry.m_aLoc);
  81             }
  82         }
  83     }
  84
  85     Entry aEntry;
  86     aEntry.m_aLoc = aLoc;
  87     aEntry.m_aMacroName = m_rPP.getSpelling(rMacroNameTok);
  88     m_aDefStack.push_back(aEntry);
  89 }
  90
  91 void RedundantPreprocessor::Ifndef(clang::SourceLocation aLoc, const clang::Token& rMacroNameTok,
  92                                    const clang::MacroDefinition& /*rMacroDefinition*/)
  93 {
  94     if (ignoreLocation(aLoc))
  95         return;
  96
  97     if (m_rPP.getSourceManager().isInMainFile(aLoc))
  98     {
  99         std::string aMacroName = m_rPP.getSpelling(rMacroNameTok);
 100         for (const auto& rEntry : m_aNotDefStack)
 101         {
 102             if (rEntry.m_aMacroName == aMacroName)
 103             {
 104                 report(DiagnosticsEngine::Warning, "nested ifndef", aLoc);
 105                 report(DiagnosticsEngine::Note, "previous ifndef", rEntry.m_aLoc);
 106             }
 107         }
 108     }
 109
 110     Entry aEntry;
 111     aEntry.m_aLoc = aLoc;
 112     aEntry.m_aMacroName = m_rPP.getSpelling(rMacroNameTok);
 113     m_aNotDefStack.push_back(aEntry);
 114 }
 115
 116 void RedundantPreprocessor::Endif(clang::SourceLocation /*aLoc*/, clang::SourceLocation aIfLoc)
 117 {
 118     if (!m_aDefStack.empty())
 119     {
 120         if (aIfLoc == m_aDefStack.back().m_aLoc)
 121             m_aDefStack.pop_back();
 122     }
 123     if (!m_aNotDefStack.empty())
 124     {
 125         if (aIfLoc == m_aNotDefStack.back().m_aLoc)
 126             m_aNotDefStack.pop_back();
 127     }
 128 }
 129
 130 static Plugin::Registration<RedundantPreprocessor> X("redundantpreprocessor");
 131 }
 132
 133 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */