1 files changed, 133 insertions, 0 deletions
diff --git a/compilerplugins/clang/readability-redundant-pp.cxx b/compilerplugins/clang/readability-redundant-pp.cxx
new file mode 100644
index 0000000000..dcfd70247f
--- /dev/null
+++ b/compilerplugins/clang/readability-redundant-pp.cxx
@@ -0,0 +1,133 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * Based on LLVM/Clang.
+ *
+ * This file is distributed under the University of Illinois Open Source
+ * License. See LICENSE.TXT for details.
+ *
+ */
+
+#include <iostream>
+#include <stack>
+
+#include "plugin.hxx"
+
+#include <clang/Frontend/CompilerInstance.h>
+#include <clang/Frontend/FrontendActions.h>
+#include <clang/Tooling/CommonOptionsParser.h>
+#include <clang/Tooling/Refactoring.h>
+#include <llvm/Support/Signals.h>
+
+/// Finds preprocessor usage which is redundant (only #ifndef for now).
+
+namespace
+{
+struct Entry
+{
+    clang::SourceLocation m_aLoc;
+    std::string m_aMacroName;
+};
+
+class RedundantPreprocessor : public clang::PPCallbacks, public loplugin::Plugin
+{
+public:
+    explicit RedundantPreprocessor(const loplugin::InstantiationData& data);
+    virtual void run() override;
+    void Ifndef(clang::SourceLocation aLoc, const clang::Token& rMacroNameTok,
+                const clang::MacroDefinition& rMacroDefinition) override;
+    void Ifdef(clang::SourceLocation aLoc, const clang::Token& rMacroNameTok,
+               const clang::MacroDefinition& rMacroDefinition) override;
+    void Endif(clang::SourceLocation aLoc, clang::SourceLocation aIfLoc) override;
+    enum
+    {
+        isPPCallback = true
+    };
+
+private:
+    clang::Preprocessor& m_rPP;
+    std::vector<Entry> m_aDefStack;
+    std::vector<Entry> m_aNotDefStack;
+};
+
+RedundantPreprocessor::RedundantPreprocessor(const loplugin::InstantiationData& data)
+    : Plugin(data)
+    , m_rPP(compiler.getPreprocessor())
+{
+    compiler.getPreprocessor().addPPCallbacks(std::unique_ptr<PPCallbacks>(this));
+}
+
+void RedundantPreprocessor::run()
+{
+    // nothing, only check preprocessor usage
+}
+
+void RedundantPreprocessor::Ifdef(clang::SourceLocation aLoc, const clang::Token& rMacroNameTok,
+                                  const clang::MacroDefinition& /*rMacroDefinition*/)
+{
+    if (ignoreLocation(aLoc))
+        return;
+
+    std::string aMacroName = m_rPP.getSpelling(rMacroNameTok);
+    if (m_rPP.getSourceManager().isInMainFile(aLoc))
+    {
+        for (const auto& rEntry : m_aDefStack)
+        {
+            if (rEntry.m_aMacroName == aMacroName)
+            {
+                report(DiagnosticsEngine::Warning, "nested ifdef", aLoc);
+                report(DiagnosticsEngine::Note, "previous ifdef", rEntry.m_aLoc);
+            }
+        }
+    }
+
+    Entry aEntry;
+    aEntry.m_aLoc = aLoc;
+    aEntry.m_aMacroName = aMacroName;
+    m_aDefStack.push_back(aEntry);
+}
+
+void RedundantPreprocessor::Ifndef(clang::SourceLocation aLoc, const clang::Token& rMacroNameTok,
+                                   const clang::MacroDefinition& /*rMacroDefinition*/)
+{
+    if (ignoreLocation(aLoc))
+        return;
+
+    std::string aMacroName = m_rPP.getSpelling(rMacroNameTok);
+    if (m_rPP.getSourceManager().isInMainFile(aLoc))
+    {
+        for (const auto& rEntry : m_aNotDefStack)
+        {
+            if (rEntry.m_aMacroName == aMacroName)
+            {
+                report(DiagnosticsEngine::Warning, "nested ifndef", aLoc);
+                report(DiagnosticsEngine::Note, "previous ifndef", rEntry.m_aLoc);
+            }
+        }
+    }
+
+    Entry aEntry;
+    aEntry.m_aLoc = aLoc;
+    aEntry.m_aMacroName = aMacroName;
+    m_aNotDefStack.push_back(aEntry);
+}
+
+void RedundantPreprocessor::Endif(clang::SourceLocation /*aLoc*/, clang::SourceLocation aIfLoc)
+{
+    if (!m_aDefStack.empty())
+    {
+        if (aIfLoc == m_aDefStack.back().m_aLoc)
+            m_aDefStack.pop_back();
+    }
+    if (!m_aNotDefStack.empty())
+    {
+        if (aIfLoc == m_aNotDefStack.back().m_aLoc)
+            m_aNotDefStack.pop_back();
+    }
+}
+
+loplugin::Plugin::Registration<RedundantPreprocessor> X("redundantpreprocessor");
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */