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/* -*- 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 <fstream>
#include <set>
#include <clang/AST/CXXInheritance.h>
#include "plugin.hxx"
/**
look for methods where all they do is call their superclass method
*/
namespace {
bool hasMultipleBaseInstances_(
CXXRecordDecl const * derived, CXXRecordDecl const * canonicBase,
bool & hasAsNonVirtualBase, bool & hasAsVirtualBase)
{
for (auto i = derived->bases_begin(); i != derived->bases_end(); ++i) {
auto const cls = i->getType()->getAsCXXRecordDecl();
if (cls == nullptr) {
assert(i->getType()->isDependentType());
// Conservatively assume "yes" for dependent bases:
return true;
}
if (cls->getCanonicalDecl() == canonicBase) {
if (i->isVirtual()) {
if (hasAsNonVirtualBase) {
return true;
}
hasAsVirtualBase = true;
} else {
if (hasAsNonVirtualBase || hasAsVirtualBase) {
return true;
}
hasAsNonVirtualBase = true;
}
} else if (hasMultipleBaseInstances_(
cls, canonicBase, hasAsNonVirtualBase, hasAsVirtualBase))
{
return true;
}
}
return false;
}
bool hasMultipleBaseInstances(
CXXRecordDecl const * derived, CXXRecordDecl const * base)
{
bool nonVirt = false;
bool virt = false;
return hasMultipleBaseInstances_(
derived, base->getCanonicalDecl(), nonVirt, virt);
}
class UnnecessaryOverride:
public RecursiveASTVisitor<UnnecessaryOverride>, public loplugin::Plugin
{
public:
explicit UnnecessaryOverride(loplugin::InstantiationData const & data): Plugin(data) {}
virtual void run() override
{
// ignore some files with problematic macros
StringRef fn(handler.getMainFileName());
if (loplugin::isSamePathname(fn, SRCDIR "/sd/source/ui/framework/factories/ChildWindowPane.cxx"))
return;
if (loplugin::isSamePathname(fn, SRCDIR "/forms/source/component/Date.cxx"))
return;
if (loplugin::isSamePathname(fn, SRCDIR "/forms/source/component/Time.cxx"))
return;
if (loplugin::isSamePathname(fn, SRCDIR "/svx/source/dialog/hyperdlg.cxx"))
return;
if (loplugin::isSamePathname(fn, SRCDIR "/svx/source/dialog/rubydialog.cxx"))
return;
if (loplugin::hasPathnamePrefix(fn, SRCDIR "/canvas/"))
return;
if (loplugin::isSamePathname(fn, SRCDIR "/sc/source/ui/view/spelldialog.cxx"))
return;
if (loplugin::isSamePathname(fn, SRCDIR "/sd/source/ui/dlg/SpellDialogChildWindow.cxx"))
return;
// HAVE_ODBC_ADMINISTRATION
if (loplugin::isSamePathname(fn, SRCDIR "/dbaccess/source/ui/dlg/dsselect.cxx"))
return;
TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
}
bool VisitCXXMethodDecl(const CXXMethodDecl *);
private:
const CXXMethodDecl * findOverriddenOrSimilarMethodInSuperclasses(const CXXMethodDecl *);
bool BaseCheckCallback(const CXXRecordDecl *BaseDefinition);
};
bool UnnecessaryOverride::VisitCXXMethodDecl(const CXXMethodDecl* methodDecl)
{
if (ignoreLocation(methodDecl->getCanonicalDecl())) {
return true;
}
if (isa<CXXConstructorDecl>(methodDecl)) {
return true;
}
StringRef aFileName = getFileNameOfSpellingLoc(
compiler.getSourceManager().getSpellingLoc(compat::getBeginLoc(methodDecl)));
if (isa<CXXDestructorDecl>(methodDecl)
&& !isInUnoIncludeFile(methodDecl))
{
// the code is this method is only __compiled__ if OSL_DEBUG_LEVEL > 1
if (loplugin::isSamePathname(aFileName, SRCDIR "/tools/source/stream/strmunx.cxx"))
return true;
// Warn about unnecessarily user-declared destructors.
// A destructor is deemed unnecessary if:
// * it is public;
// * its class is only defined in the .cxx file (i.e., the virtual
// destructor is neither used to control the place of vtable
// emission, nor is its definition depending on types that may still
// be incomplete);
// or
// the destructor is inline, the class definition is complete,
// and the class has no superclasses
// * it either does not have an explicit exception specification, or has
// a non-dependent explicit exception specification that is compatible
// with a non-dependent exception specification the destructor would
// have if it did not have an explicit one (TODO);
// * it is either defined as defaulted or with an empty body.
// Removing the user-declared destructor may cause the class to get an
// implicitly declared move constructor and/or move assignment operator;
// that is considered acceptable: If any subobject cannot be moved, the
// implicitly declared function will be defined as deleted (which is in
// practice not much different from not having it declared), and
// otherwise offering movability is likely even an improvement over not
// offering it due to a "pointless" user-declared destructor.
// Similarly, removing the user-declared destructor may cause the
// implicit definition of a copy constructor and/or copy assignment
// operator to change from being an obsolete feature to being a standard
// feature. That difference is not taken into account here.
auto cls = methodDecl->getParent();
if (methodDecl->getAccess() != AS_public)
{
return true;
}
if (!compiler.getSourceManager().isInMainFile(
methodDecl->getCanonicalDecl()->getLocation())
&& !( methodDecl->isInlined()))
{
return true;
}
// if it's virtual, but it has a base-class with a non-virtual destructor
if (methodDecl->isVirtual())
{
bool baseWithVirtualDtor = false;
for (auto baseSpecifier = cls->bases_begin(); baseSpecifier != cls->bases_end(); ++baseSpecifier)
{
const RecordType* baseRecordType = baseSpecifier->getType()->getAs<RecordType>();
if (baseRecordType)
{
const CXXRecordDecl* baseRecordDecl = dyn_cast<CXXRecordDecl>(baseRecordType->getDecl());
if (baseRecordDecl && baseRecordDecl->getDestructor()
&& baseRecordDecl->getDestructor()->isVirtual())
{
baseWithVirtualDtor = true;
break;
}
}
}
if (!baseWithVirtualDtor)
{
return true;
}
}
// corner case
if (methodDecl->isInlined()
&& compiler.getSourceManager().isInMainFile(methodDecl->getLocation())
&& !compiler.getSourceManager().isInMainFile(methodDecl->getCanonicalDecl()->getLocation()))
{
return true;
}
if (!methodDecl->isExplicitlyDefaulted()) {
if (!methodDecl->doesThisDeclarationHaveABody()
|| methodDecl->isLateTemplateParsed())
{
return true;
}
auto stmt = dyn_cast<CompoundStmt>(methodDecl->getBody());
if (stmt == nullptr || stmt->size() != 0) {
return true;
}
}
//TODO: exception specification
if (!(cls->hasUserDeclaredCopyConstructor()
|| cls->hasUserDeclaredCopyAssignment()
|| cls->hasUserDeclaredMoveConstructor()
|| cls->hasUserDeclaredMoveAssignment()))
{
}
if ((cls->needsImplicitMoveConstructor()
&& !(cls->hasUserDeclaredCopyConstructor()
|| cls->hasUserDeclaredCopyAssignment()
|| cls->hasUserDeclaredMoveAssignment()))
|| (cls->needsImplicitMoveAssignment()
&& !(cls->hasUserDeclaredCopyConstructor()
|| cls->hasUserDeclaredCopyAssignment()
|| cls->hasUserDeclaredMoveConstructor())))
{
report(DiagnosticsEngine::Fatal, "TODO", methodDecl->getLocation());
return true;
}
report(
DiagnosticsEngine::Warning, "unnecessary user-declared destructor",
methodDecl->getLocation())
<< methodDecl->getSourceRange();
auto cd = methodDecl->getCanonicalDecl();
if (cd->getLocation() != methodDecl->getLocation()) {
report(DiagnosticsEngine::Note, "declared here", cd->getLocation())
<< cd->getSourceRange();
}
return true;
}
if (!methodDecl->doesThisDeclarationHaveABody()
|| methodDecl->isLateTemplateParsed())
{
return true;
}
// If overriding more than one base member function, or one base member
// function that is available in multiple (non-virtual) base class
// instances, then this is a disambiguating override:
if (methodDecl->isVirtual()) {
if (methodDecl->size_overridden_methods() != 1)
{
return true;
}
if (hasMultipleBaseInstances(
methodDecl->getParent(),
(*methodDecl->begin_overridden_methods())->getParent()))
{
return true;
}
}
const CXXMethodDecl* overriddenMethodDecl = findOverriddenOrSimilarMethodInSuperclasses(methodDecl);
if (!overriddenMethodDecl) {
return true;
}
// Check for differences in default parameters:
unsigned const numParams = methodDecl->getNumParams();
assert(overriddenMethodDecl->getNumParams() == numParams);
for (unsigned i = 0; i != numParams; ++i) {
if (checkIdenticalDefaultArguments(
methodDecl->getParamDecl(i)->getDefaultArg(),
overriddenMethodDecl->getParamDecl(i)->getDefaultArg())
!= IdenticalDefaultArgumentsResult::Yes)
{
return true;
}
}
if (methodDecl->getReturnType().getCanonicalType()
!= overriddenMethodDecl->getReturnType().getCanonicalType())
{
return true;
}
//TODO: check for identical exception specifications
const CompoundStmt* compoundStmt = dyn_cast<CompoundStmt>(methodDecl->getBody());
if (!compoundStmt || compoundStmt->size() != 1)
return true;
const CXXMemberCallExpr* callExpr = nullptr;
if (methodDecl->getReturnType().getCanonicalType()->isVoidType())
{
if (auto const e = dyn_cast<Expr>(*compoundStmt->body_begin())) {
callExpr = dyn_cast<CXXMemberCallExpr>(e->IgnoreImplicit()->IgnoreParens());
}
}
else
{
auto returnStmt = dyn_cast<ReturnStmt>(*compoundStmt->body_begin());
if (returnStmt == nullptr) {
return true;
}
auto returnExpr = returnStmt->getRetValue();
if (returnExpr == nullptr) {
return true;
}
returnExpr = returnExpr->IgnoreImplicit();
// In something like
//
// Reference< XResultSet > SAL_CALL OPreparedStatement::executeQuery(
// const rtl::OUString& sql)
// throw(SQLException, RuntimeException, std::exception)
// {
// return OCommonStatement::executeQuery( sql );
// }
//
// look down through all the
//
// ReturnStmt
// `-ExprWithCleanups
// `-CXXConstructExpr
// `-MaterializeTemporaryExpr
// `-ImplicitCastExpr
// `-CXXBindTemporaryExpr
// `-CXXMemberCallExpr
//
// where the fact that the overriding and overridden function have identical
// return types makes us confident that all we need to check here is whether
// there's an (arbitrary, one-argument) CXXConstructorExpr and
// CXXBindTemporaryExpr in between:
if (auto ctorExpr = dyn_cast<CXXConstructExpr>(returnExpr)) {
if (ctorExpr->getNumArgs() == 1) {
auto tempExpr1 = ctorExpr->getArg(0)->IgnoreImplicit();
if (auto tempExpr2 = dyn_cast<CXXBindTemporaryExpr>(tempExpr1))
{
returnExpr = tempExpr2->getSubExpr();
}
else if (auto tempExpr2 = dyn_cast<CXXMemberCallExpr>(tempExpr1))
{
returnExpr = tempExpr2;
}
}
}
callExpr = dyn_cast<CXXMemberCallExpr>(returnExpr->IgnoreParenImpCasts());
}
if (!callExpr || callExpr->getMethodDecl() != overriddenMethodDecl)
return true;
const Expr* expr1 = callExpr->getImplicitObjectArgument()->IgnoreImpCasts();
if (!expr1)
return true;
const CXXThisExpr* expr2 = dyn_cast_or_null<CXXThisExpr>(expr1);
if (!expr2)
return true;
for (unsigned i = 0; i<callExpr->getNumArgs(); ++i) {
auto e = callExpr->getArg(i)->IgnoreImplicit();
if (auto const e1 = dyn_cast<CXXConstructExpr>(e)) {
if (e1->getConstructor()->isCopyOrMoveConstructor() && e1->getNumArgs() == 1) {
e = e1->getArg(0)->IgnoreImpCasts();
}
}
const DeclRefExpr * declRefExpr = dyn_cast<DeclRefExpr>(e);
if (!declRefExpr || declRefExpr->getDecl() != methodDecl->getParamDecl(i))
return true;
}
report(
DiagnosticsEngine::Warning, "%0%1 function just calls %2 parent",
methodDecl->getLocation())
<< methodDecl->getAccess()
<< (methodDecl->isVirtual() ? " virtual" : "")
<< overriddenMethodDecl->getAccess()
<< methodDecl->getSourceRange();
if (methodDecl->getCanonicalDecl()->getLocation() != methodDecl->getLocation()) {
const CXXMethodDecl* pOther = methodDecl->getCanonicalDecl();
report(
DiagnosticsEngine::Note,
"method declaration here",
pOther->getLocation())
<< pOther->getSourceRange();
}
return true;
}
const CXXMethodDecl* UnnecessaryOverride::findOverriddenOrSimilarMethodInSuperclasses(const CXXMethodDecl* methodDecl)
{
if (methodDecl->isVirtual()) {
return *methodDecl->begin_overridden_methods();
}
if (!methodDecl->getDeclName().isIdentifier()) {
return nullptr;
}
const CXXMethodDecl* similarMethod = nullptr;
CXXBasePath similarBasePath;
auto BaseMatchesCallback = [&](const CXXBaseSpecifier *cxxBaseSpecifier, CXXBasePath& path)
{
if (cxxBaseSpecifier->getAccessSpecifier() != AS_public && cxxBaseSpecifier->getAccessSpecifier() != AS_protected)
return false;
if (!cxxBaseSpecifier->getType().getTypePtr())
return false;
const CXXRecordDecl* baseCXXRecordDecl = cxxBaseSpecifier->getType()->getAsCXXRecordDecl();
if (!baseCXXRecordDecl)
return false;
if (baseCXXRecordDecl->isInvalidDecl())
return false;
for (const CXXMethodDecl* baseMethod : baseCXXRecordDecl->methods())
{
auto effectiveBaseMethodAccess = baseMethod->getAccess();
if (effectiveBaseMethodAccess == AS_public && path.Access == AS_protected)
effectiveBaseMethodAccess = AS_protected;
if (effectiveBaseMethodAccess != methodDecl->getAccess())
continue;
if (!baseMethod->getDeclName().isIdentifier() || methodDecl->getName() != baseMethod->getName()) {
continue;
}
if (methodDecl->isStatic() != baseMethod->isStatic()
|| methodDecl->isConst() != baseMethod->isConst()
|| methodDecl->isVolatile() != baseMethod->isVolatile()
|| (methodDecl->getRefQualifier()
!= baseMethod->getRefQualifier())
|| methodDecl->isVariadic() != baseMethod->isVariadic())
{
continue;
}
if (methodDecl->getReturnType().getCanonicalType()
!= baseMethod->getReturnType().getCanonicalType())
{
continue;
}
if (methodDecl->getNumParams() != baseMethod->getNumParams())
continue;
bool bParamsMatch = true;
for (unsigned i=0; i<methodDecl->param_size(); ++i)
{
if (methodDecl->parameters()[i]->getType() != baseMethod->parameters()[i]->getType())
{
bParamsMatch = false;
break;
}
}
if (bParamsMatch)
{
// if we have already found a method directly below us in the inheritance hierarchy, just ignore this one
auto Compare = [&](CXXBasePathElement const & lhs, CXXBasePathElement const & rhs)
{
return lhs.Class == rhs.Class;
};
if (similarMethod
&& similarBasePath.size() < path.size()
&& std::equal(similarBasePath.begin(), similarBasePath.end(),
path.begin(), Compare))
break;
if (similarMethod)
return true; // short circuit the process
similarMethod = baseMethod;
similarBasePath = path;
}
}
return false;
};
CXXBasePaths aPaths;
if (methodDecl->getParent()->lookupInBases(BaseMatchesCallback, aPaths))
return nullptr;
return similarMethod;
}
loplugin::Plugin::Registration< UnnecessaryOverride > X("unnecessaryoverride", true);
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
|