1 files changed, 169 insertions, 0 deletions
diff --git a/compilerplugins/clang/mergeclasses.cxx b/compilerplugins/clang/mergeclasses.cxx
new file mode 100644
index 000000000..0f0d73d70
--- /dev/null
+++ b/compilerplugins/clang/mergeclasses.cxx
@@ -0,0 +1,169 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+#include <cassert>
+#include <set>
+#include <string>
+#include <iostream>
+#include "plugin.hxx"
+#include <fstream>
+
+/**
+
+Idea from Norbert (shm_get) - look for classes that are
+(a) not instantiated
+(b) have zero or one subclasses
+and warn about them - would allow us to remove a bunch of abstract classes
+that can be merged into one class and simplified.
+
+Dump a list of
+- unique classes that exist (A)
+- unique classes that are instantiated (B)
+- unique class-subclass relationships (C)
+Then
+   let D = A minus B
+   for each class in D, look in C and count the entries, then dump it if no-entries == 1
+
+The process goes something like this:
+  $ make check
+  $ make FORCE_COMPILE_ALL=1 COMPILER_PLUGIN_TOOL='mergeclasses' check
+  $ ./compilerplugins/clang/mergeclasses.py
+
+FIXME exclude 'static-only' classes, which some people may use/have used instead of a namespace to tie together a bunch of functions
+
+*/
+
+namespace {
+
+// try to limit the voluminous output a little
+static std::set<std::string> instantiatedSet;
+static std::set<std::pair<std::string,std::string> > childToParentClassSet; // childClassName -> parentClassName
+static std::map<std::string,std::string> definitionMap;  // className -> filename
+
+class MergeClasses:
+    public loplugin::FilteringPlugin<MergeClasses>
+{
+public:
+    explicit MergeClasses(loplugin::InstantiationData const & data):
+        FilteringPlugin(data) {}
+
+    virtual void run() override
+    {
+        TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+
+        // dump all our output in one write call - this is to try and limit IO "crosstalk" between multiple processes
+        // writing to the same logfile
+        std::string output;
+        for (const std::string & s : instantiatedSet)
+            output += "instantiated:\t" + s + "\n";
+        for (const std::pair<std::string,std::string> & s : childToParentClassSet)
+            output += "has-subclass:\t" + s.first + "\t" + s.second + "\n";
+        for (const auto & s : definitionMap)
+            output += "definition:\t" + s.first + "\t" + s.second + "\n";
+        std::ofstream myfile;
+        myfile.open( WORKDIR "/loplugin.mergeclasses.log", std::ios::app | std::ios::out);
+        myfile << output;
+        myfile.close();
+    }
+
+    bool shouldVisitTemplateInstantiations () const { return true; }
+
+    bool VisitVarDecl(const VarDecl *);
+    bool VisitFieldDecl(const FieldDecl *);
+    bool VisitCXXConstructExpr( const CXXConstructExpr* var );
+    bool VisitCXXRecordDecl( const CXXRecordDecl* decl);
+};
+
+bool ignoreClass(StringRef s)
+{
+    // ignore stuff in the standard library, and UNO stuff we can't touch.
+    if (s.startswith("rtl::") || s.startswith("sal::") || s.startswith("com::sun::")
+        || s.startswith("std::") || s.startswith("boost::")
+        || s == "OString" || s == "OUString" || s == "bad_alloc")
+    {
+        return true;
+    }
+    // ignore instantiations of pointers and arrays
+    if (s.endswith("*") || s.endswith("]")) {
+        return true;
+    }
+    return false;
+}
+
+// check for implicit construction
+bool MergeClasses::VisitVarDecl( const VarDecl* pVarDecl )
+{
+    if (ignoreLocation(pVarDecl)) {
+        return true;
+    }
+    std::string s = pVarDecl->getType().getAsString();
+    if (!ignoreClass(s))
+        instantiatedSet.insert(s);
+    return true;
+}
+
+// check for implicit construction
+bool MergeClasses::VisitFieldDecl( const FieldDecl* pFieldDecl )
+{
+    if (ignoreLocation(pFieldDecl)) {
+        return true;
+    }
+    std::string s = pFieldDecl->getType().getAsString();
+    if (!ignoreClass(s))
+        instantiatedSet.insert(s);
+    return true;
+}
+
+bool MergeClasses::VisitCXXConstructExpr( const CXXConstructExpr* pCXXConstructExpr )
+{
+    if (ignoreLocation(pCXXConstructExpr)) {
+        return true;
+    }
+    // ignore calls when a sub-class is constructing its superclass
+    if (pCXXConstructExpr->getConstructionKind() != CXXConstructExpr::ConstructionKind::CK_Complete) {
+        return true;
+    }
+    const CXXConstructorDecl* pCXXConstructorDecl = pCXXConstructExpr->getConstructor();
+    const CXXRecordDecl* pParentCXXRecordDecl = pCXXConstructorDecl->getParent();
+    std::string s = pParentCXXRecordDecl->getQualifiedNameAsString();
+    if (!ignoreClass(s))
+        instantiatedSet.insert(s);
+    return true;
+}
+
+bool MergeClasses::VisitCXXRecordDecl(const CXXRecordDecl* decl)
+{
+    if (ignoreLocation(decl)) {
+        return true;
+    }
+    if (decl->isThisDeclarationADefinition())
+    {
+        SourceLocation spellingLocation = compiler.getSourceManager().getSpellingLoc(compat::getBeginLoc(decl));
+        auto filename = getFilenameOfLocation(spellingLocation);
+        filename = filename.substr(strlen(SRCDIR));
+        std::string s = decl->getQualifiedNameAsString();
+        if (ignoreClass(s))
+            return true;
+        definitionMap.insert( std::pair<std::string,std::string>(s, filename.str()) );
+        for (auto it = decl->bases_begin(); it != decl->bases_end(); ++it)
+        {
+            const CXXBaseSpecifier spec = *it;
+            // need to look through typedefs, hence the getUnqualifiedDesugaredType
+            QualType baseType = spec.getType().getDesugaredType(compiler.getASTContext());
+            childToParentClassSet.insert( std::pair<std::string,std::string>(s, baseType.getAsString()) );
+        }
+    }
+    return true;
+}
+
+loplugin::Plugin::Registration< MergeClasses > X("mergeclasses", false);
+
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */