new loplugin:duplicate-defines

Change-Id: I98e17e0a92ae5d51778b9a72c679ed262a6f5cb0
Reviewed-on: https://gerrit.libreoffice.org/79826
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

compilerplugins/clang/duplicate-defines.cxx

@@ -0,0 +1,105 @@
+/* -*- 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 <unordered_map>
+
+#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 duplicated preprocessor defines, which generally indicate that some definition
+/// needs to be centralised somewhere.
+
+namespace loplugin
+{
+struct Entry
+{
+    clang::SourceLocation m_aLoc;
+};
+
+class DuplicateDefines : public clang::PPCallbacks, public Plugin
+{
+public:
+    explicit DuplicateDefines(const InstantiationData& data);
+    virtual void run() override;
+    void MacroDefined(const Token& MacroNameTok, const MacroDirective* MD);
+    void MacroUndefined(const Token& MacroNameTok, const MacroDefinition& MD,
+                        const MacroDirective* Undef);
+    enum
+    {
+        isPPCallback = true
+    };
+
+private:
+    clang::Preprocessor& m_rPP;
+    std::unordered_map<std::string, Entry> m_aDefMap;
+};
+
+DuplicateDefines::DuplicateDefines(const InstantiationData& data)
+    : Plugin(data)
+    , m_rPP(compiler.getPreprocessor())
+{
+    compiler.getPreprocessor().addPPCallbacks(std::unique_ptr<PPCallbacks>(this));
+}
+
+void DuplicateDefines::run()
+{
+    // nothing, only check preprocessor usage
+}
+
+void DuplicateDefines::MacroDefined(const Token& rMacroNameTok, const MacroDirective*)
+{
+    auto aLoc = rMacroNameTok.getLocation();
+    if (ignoreLocation(aLoc))
+        return;
+
+    std::string aMacroName = m_rPP.getSpelling(rMacroNameTok);
+
+    // some testing macro
+    if (aMacroName == "RTL_STRING_CONST_FUNCTION")
+        return;
+    if (aMacroName == "rtl")
+        return;
+    // we replicate this macro in all the .hrc files
+    if (aMacroName == "NC_")
+        return;
+    // TODO no obvious fix for these
+    if (aMacroName == "FID_SEARCH_NOW" || aMacroName == "FID_SVX_START" || aMacroName == "FN_PARAM")
+        return;
+
+    if (!m_aDefMap.emplace(aMacroName, Entry{ aLoc }).second)
+    {
+        report(DiagnosticsEngine::Warning, "duplicate defines", aLoc);
+        report(DiagnosticsEngine::Note, "previous define", m_aDefMap[aMacroName].m_aLoc);
+        return;
+    }
+}
+
+void DuplicateDefines::MacroUndefined(const Token& rMacroNameTok, const MacroDefinition& /*MD*/,
+                                      const MacroDirective* /*Undef*/)
+{
+    auto aLoc = rMacroNameTok.getLocation();
+    if (ignoreLocation(aLoc))
+        return;
+
+    std::string aMacroName = m_rPP.getSpelling(rMacroNameTok);
+    m_aDefMap.erase(aMacroName);
+}
+
+static Plugin::Registration<DuplicateDefines> X("duplicatedefines", false);
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */