1 files changed, 219 insertions, 0 deletions
diff --git a/compilerplugins/clang/virtualdown.cxx b/compilerplugins/clang/virtualdown.cxx
new file mode 100644
index 000000000..946d8bc95
--- /dev/null
+++ b/compilerplugins/clang/virtualdown.cxx
@@ -0,0 +1,219 @@
+/* -*- 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 <string>
+#include <iostream>
+#include <set>
+#include "config_clang.h"
+#include "plugin.hxx"
+#include <fstream>
+
+/**
+Look for virtual methods where we never call the defining virtual method, and only call the overriding virtual
+methods, which indicates a places where the virtual-ness is unwarranted, normally a result of premature abstraction.
+
+The process goes something like this:
+  $ make check
+  $ make FORCE_COMPILE=all COMPILER_PLUGIN_TOOL='VirtualDown' check
+  $ ./compilerplugins/clang/VirtualDown.py
+
+@TODO for some reason, we get false+ for operator== methods
+@TODO some templates confuse it and we get false+
+
+*/
+
+namespace
+{
+struct MyFuncInfo
+{
+    std::string name;
+    std::string sourceLocation;
+};
+bool operator<(const MyFuncInfo& lhs, const MyFuncInfo& rhs) { return lhs.name < rhs.name; }
+
+// try to limit the voluminous output a little
+static std::set<MyFuncInfo> definitionSet;
+static std::set<std::string> callSet;
+
+class VirtualDown : public loplugin::FilteringPlugin<VirtualDown>
+{
+public:
+    explicit VirtualDown(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 MyFuncInfo& s : definitionSet)
+            output += "definition:\t" + s.name + "\t" + s.sourceLocation + "\n";
+        for (const std::string& s : callSet)
+            output += "call:\t" + s + "\n";
+        std::ofstream myfile;
+        myfile.open(WORKDIR "/loplugin.virtualdown.log", std::ios::app | std::ios::out);
+        myfile << output;
+        myfile.close();
+    }
+    bool shouldVisitTemplateInstantiations() const { return true; }
+    bool shouldVisitImplicitCode() const { return true; }
+
+    bool VisitCXXMethodDecl(CXXMethodDecl const*);
+    bool VisitCXXMemberCallExpr(CXXMemberCallExpr const*);
+    bool TraverseFunctionDecl(FunctionDecl*);
+    bool TraverseCXXMethodDecl(CXXMethodDecl*);
+    bool TraverseCXXConversionDecl(CXXConversionDecl*);
+    bool TraverseCXXDeductionGuideDecl(CXXDeductionGuideDecl*);
+
+private:
+    std::string toString(SourceLocation loc);
+    std::string niceName(const CXXMethodDecl* functionDecl);
+    FunctionDecl const* currentFunctionDecl = nullptr;
+};
+
+bool VirtualDown::VisitCXXMethodDecl(const CXXMethodDecl* methodDecl)
+{
+    if (ignoreLocation(methodDecl))
+    {
+        return true;
+    }
+    if (!methodDecl->isThisDeclarationADefinition() || !methodDecl->isVirtual()
+        || methodDecl->isDeleted())
+    {
+        return true;
+    }
+    methodDecl = methodDecl->getCanonicalDecl();
+    // ignore stuff that forms part of the stable URE interface
+    if (isInUnoIncludeFile(methodDecl))
+    {
+        return true;
+    }
+
+    std::string aNiceName = niceName(methodDecl);
+
+    if (isa<CXXDestructorDecl>(methodDecl))
+        return true;
+    if (isa<CXXConstructorDecl>(methodDecl))
+        return true;
+
+    if (methodDecl->size_overridden_methods() == 0)
+        definitionSet.insert({ aNiceName, toString(methodDecl->getLocation()) });
+
+    return true;
+}
+
+bool VirtualDown::VisitCXXMemberCallExpr(CXXMemberCallExpr const* expr)
+{
+    // Note that I don't ignore ANYTHING here, because I want to get calls to my code that result
+    // from template instantiation deep inside the STL and other external code
+
+    FunctionDecl const* calleeFunctionDecl = expr->getDirectCallee();
+    if (calleeFunctionDecl == nullptr)
+    {
+        Expr const* callee = expr->getCallee()->IgnoreParenImpCasts();
+        DeclRefExpr const* dr = dyn_cast<DeclRefExpr>(callee);
+        if (dr)
+        {
+            calleeFunctionDecl = dyn_cast<FunctionDecl>(dr->getDecl());
+            if (calleeFunctionDecl)
+                goto gotfunc;
+        }
+        return true;
+    }
+
+gotfunc:
+
+    // ignore recursive calls
+    if (currentFunctionDecl == calleeFunctionDecl)
+        return true;
+
+    auto cxxMethodDecl = dyn_cast<CXXMethodDecl>(calleeFunctionDecl);
+    if (!cxxMethodDecl)
+        return true;
+
+    while (cxxMethodDecl->getTemplateInstantiationPattern())
+        cxxMethodDecl = dyn_cast<CXXMethodDecl>(cxxMethodDecl->getTemplateInstantiationPattern());
+    while (cxxMethodDecl->getInstantiatedFromMemberFunction())
+        cxxMethodDecl = dyn_cast<CXXMethodDecl>(cxxMethodDecl->getInstantiatedFromMemberFunction());
+    if (cxxMethodDecl->getLocation().isValid() && !ignoreLocation(cxxMethodDecl))
+        callSet.insert(niceName(cxxMethodDecl));
+
+    return true;
+}
+
+bool VirtualDown::TraverseFunctionDecl(FunctionDecl* f)
+{
+    auto copy = currentFunctionDecl;
+    currentFunctionDecl = f;
+    bool ret = RecursiveASTVisitor::TraverseFunctionDecl(f);
+    currentFunctionDecl = copy;
+    return ret;
+}
+bool VirtualDown::TraverseCXXMethodDecl(CXXMethodDecl* f)
+{
+    auto copy = currentFunctionDecl;
+    currentFunctionDecl = f;
+    bool ret = RecursiveASTVisitor::TraverseCXXMethodDecl(f);
+    currentFunctionDecl = copy;
+    return ret;
+}
+bool VirtualDown::TraverseCXXConversionDecl(CXXConversionDecl* f)
+{
+    auto copy = currentFunctionDecl;
+    currentFunctionDecl = f;
+    bool ret = RecursiveASTVisitor::TraverseCXXConversionDecl(f);
+    currentFunctionDecl = copy;
+    return ret;
+}
+bool VirtualDown::TraverseCXXDeductionGuideDecl(CXXDeductionGuideDecl* f)
+{
+    auto copy = currentFunctionDecl;
+    currentFunctionDecl = f;
+    bool ret = RecursiveASTVisitor::TraverseCXXDeductionGuideDecl(f);
+    currentFunctionDecl = copy;
+    return ret;
+}
+
+std::string VirtualDown::niceName(const CXXMethodDecl* cxxMethodDecl)
+{
+    std::string s = cxxMethodDecl->getReturnType().getCanonicalType().getAsString() + " "
+                    + cxxMethodDecl->getQualifiedNameAsString() + "(";
+    for (const ParmVarDecl* pParmVarDecl : cxxMethodDecl->parameters())
+    {
+        s += pParmVarDecl->getType().getCanonicalType().getAsString();
+        s += ",";
+    }
+    s += ")";
+    if (cxxMethodDecl->isConst())
+    {
+        s += "const";
+    }
+    return s;
+}
+
+std::string VirtualDown::toString(SourceLocation loc)
+{
+    SourceLocation expansionLoc = compiler.getSourceManager().getExpansionLoc(loc);
+    StringRef name = getFilenameOfLocation(expansionLoc);
+    std::string sourceLocation
+        = std::string(name.substr(strlen(SRCDIR) + 1)) + ":"
+          + std::to_string(compiler.getSourceManager().getSpellingLineNumber(expansionLoc));
+    loplugin::normalizeDotDotInFilePath(sourceLocation);
+    return sourceLocation;
+}
+
+loplugin::Plugin::Registration<VirtualDown> X("virtualdown", false);
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */