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-rw-r--r--compilerplugins/clang/virtualdead.cxx283
1 files changed, 283 insertions, 0 deletions
diff --git a/compilerplugins/clang/virtualdead.cxx b/compilerplugins/clang/virtualdead.cxx
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+++ b/compilerplugins/clang/virtualdead.cxx
@@ -0,0 +1,283 @@
+/* -*- 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 "plugin.hxx"
+#include "check.hxx"
+#include "compat.hxx"
+
+#include <cassert>
+#include <string>
+#include <iostream>
+#include <set>
+#include <fstream>
+
+/**
+Look for virtual methods where all of the overrides either
+(a) do nothing
+(b) all return the same value
+
+The process goes something like this:
+ $ make check
+ $ make FORCE_COMPILE=all COMPILER_PLUGIN_TOOL='VirtualDead' check
+ $ ./compilerplugins/clang/VirtualDead.py
+ $ for dir in *; do make FORCE_COMPILE=all UPDATE_FILES=$dir COMPILER_PLUGIN_TOOL='removevirtuals' $dir; done
+
+Note that the actual process may involve a fair amount of undoing, hand editing, and general messing around
+to get it to work :-)
+*/
+
+namespace
+{
+struct MyFuncInfo
+{
+ std::string name;
+ std::string sourceLocation;
+ std::string returnValue;
+};
+bool operator<(const MyFuncInfo& lhs, const MyFuncInfo& rhs)
+{
+ return std::tie(lhs.name, lhs.returnValue) < std::tie(rhs.name, rhs.returnValue);
+}
+struct MyParamInfo
+{
+ std::string funcName;
+ std::string paramBitField;
+};
+bool operator<(const MyParamInfo& lhs, const MyParamInfo& rhs)
+{
+ return std::tie(lhs.funcName, lhs.paramBitField) < std::tie(rhs.funcName, rhs.paramBitField);
+}
+
+// try to limit the voluminous output a little
+static std::set<MyFuncInfo> definitionSet;
+static std::set<MyParamInfo> paramUsedSet;
+
+class VirtualDead : public RecursiveASTVisitor<VirtualDead>, public loplugin::Plugin
+{
+public:
+ explicit VirtualDead(loplugin::InstantiationData const& data)
+ : Plugin(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 += "virtual:\t" + s.name + "\t" + s.sourceLocation + "\t" + s.returnValue + "\n";
+ for (const MyParamInfo& s : paramUsedSet)
+ output += "param:\t" + s.funcName + "\t" + s.paramBitField + "\n";
+ std::ofstream myfile;
+ myfile.open(WORKDIR "/loplugin.virtualdead.log", std::ios::app | std::ios::out);
+ myfile << output;
+ myfile.close();
+ }
+ bool shouldVisitTemplateInstantiations() const { return true; }
+ bool shouldVisitImplicitCode() const { return true; }
+
+ bool VisitCXXMethodDecl(const CXXMethodDecl* decl);
+
+private:
+ std::string getCallValue(const Expr* arg);
+ std::string toString(SourceLocation loc);
+ void markSuperclassMethods(const CXXMethodDecl* methodDecl, const std::string& returnValue,
+ const std::string& paramBitField);
+};
+
+std::string niceName(const CXXMethodDecl* cxxMethodDecl)
+{
+ while (cxxMethodDecl->getTemplateInstantiationPattern())
+ cxxMethodDecl = dyn_cast<CXXMethodDecl>(cxxMethodDecl->getTemplateInstantiationPattern());
+ while (cxxMethodDecl->getInstantiatedFromMemberFunction())
+ cxxMethodDecl = dyn_cast<CXXMethodDecl>(cxxMethodDecl->getInstantiatedFromMemberFunction());
+ 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;
+}
+
+bool VirtualDead::VisitCXXMethodDecl(const CXXMethodDecl* methodDecl)
+{
+ if (!methodDecl->isVirtual() || methodDecl->isDeleted())
+ return true;
+ if (isa<CXXDestructorDecl>(methodDecl))
+ return true;
+ // ignore stuff that forms part of the stable URE interface
+ if (isInUnoIncludeFile(methodDecl->getCanonicalDecl()))
+ return true;
+
+ if (!methodDecl->isThisDeclarationADefinition())
+ return true;
+
+ std::string returnValue;
+
+ auto body = methodDecl->getBody();
+ if (body)
+ {
+ auto compoundStmt = dyn_cast<CompoundStmt>(body);
+ if (!compoundStmt)
+ returnValue = "empty";
+ else if (compoundStmt->size() == 0)
+ returnValue = "empty";
+ else
+ {
+ if (auto returnStmt = dyn_cast<ReturnStmt>(*compoundStmt->body_begin()))
+ {
+ if (!returnStmt->getRetValue())
+ returnValue = "empty";
+ else
+ returnValue = getCallValue(returnStmt->getRetValue());
+ }
+ else
+ returnValue = "unknown-stmt";
+ }
+ }
+ else
+ returnValue = "empty";
+
+ std::string paramBitfield;
+ for (auto it = methodDecl->param_begin(); it != methodDecl->param_end(); ++it)
+ {
+ auto param = *it;
+ paramBitfield += param->getName().empty() ? "0" : "1";
+ }
+
+ markSuperclassMethods(methodDecl, returnValue, paramBitfield);
+
+ return true;
+}
+
+void VirtualDead::markSuperclassMethods(const CXXMethodDecl* methodDecl,
+ const std::string& returnValue,
+ std::string const& paramBitField)
+{
+ if (methodDecl->size_overridden_methods() == 0)
+ {
+ std::string aNiceName = niceName(methodDecl);
+ definitionSet.insert(
+ { aNiceName, toString(methodDecl->getCanonicalDecl()->getLocation()), returnValue });
+ paramUsedSet.insert({ aNiceName, paramBitField });
+ return;
+ }
+
+ for (auto iter = methodDecl->begin_overridden_methods();
+ iter != methodDecl->end_overridden_methods(); ++iter)
+ {
+ const CXXMethodDecl* overriddenMethod = *iter;
+ markSuperclassMethods(overriddenMethod, returnValue, paramBitField);
+ }
+}
+
+std::string VirtualDead::getCallValue(const Expr* arg)
+{
+ arg = arg->IgnoreParenCasts();
+ if (isa<CXXDefaultArgExpr>(arg))
+ {
+ arg = dyn_cast<CXXDefaultArgExpr>(arg)->getExpr();
+ }
+ arg = arg->IgnoreParenCasts();
+ // ignore this, it seems to trigger an infinite recursion
+ if (isa<UnaryExprOrTypeTraitExpr>(arg))
+ return "unknown1";
+ if (arg->isValueDependent())
+ return "unknown2";
+ APSInt x1;
+ if (compat::EvaluateAsInt(arg, x1, compiler.getASTContext()))
+ {
+ return compat::toString(x1, 10);
+ }
+ if (isa<CXXNullPtrLiteralExpr>(arg))
+ {
+ return "0";
+ }
+ if (isa<MaterializeTemporaryExpr>(arg))
+ {
+ const CXXBindTemporaryExpr* strippedArg
+ = dyn_cast_or_null<CXXBindTemporaryExpr>(arg->IgnoreParenCasts());
+ if (strippedArg)
+ {
+ auto temp = dyn_cast<CXXTemporaryObjectExpr>(strippedArg->getSubExpr());
+ if (temp->getNumArgs() == 0)
+ {
+ if (loplugin::TypeCheck(temp->getType())
+ .Class("OUString")
+ .Namespace("rtl")
+ .GlobalNamespace())
+ {
+ return "\"\"";
+ }
+ if (loplugin::TypeCheck(temp->getType())
+ .Class("OString")
+ .Namespace("rtl")
+ .GlobalNamespace())
+ {
+ return "\"\"";
+ }
+ return "defaultConstruct";
+ }
+ }
+ }
+
+ // Get the expression contents.
+ // This helps us find params which are always initialised with something like "OUString()".
+ SourceManager& SM = compiler.getSourceManager();
+ SourceLocation startLoc = arg->getBeginLoc();
+ SourceLocation endLoc = arg->getEndLoc();
+ const char* p1 = SM.getCharacterData(startLoc);
+ const char* p2 = SM.getCharacterData(endLoc);
+ if (!p1 || !p2 || (p2 - p1) < 0 || (p2 - p1) > 40)
+ {
+ return "unknown3";
+ }
+ unsigned n = Lexer::MeasureTokenLength(endLoc, SM, compiler.getLangOpts());
+ std::string s(p1, p2 - p1 + n);
+ // strip linefeed and tab characters so they don't interfere with the parsing of the log file
+ std::replace(s.begin(), s.end(), '\r', ' ');
+ std::replace(s.begin(), s.end(), '\n', ' ');
+ std::replace(s.begin(), s.end(), '\t', ' ');
+
+ // now normalize the value. For some params, like OUString, we can pass it as OUString() or "" and they are the same thing
+ if (s == "OUString()")
+ s = "\"\"";
+ else if (s == "OString()")
+ s = "\"\"";
+
+ if (s[0] == '"' || s[0] == '\'')
+ return s;
+ return "unknown4";
+}
+
+std::string VirtualDead::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<VirtualDead> X("virtualdead", false);
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */