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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 <algorithm>
#include "clang/AST/Attr.h"
#include "clang/AST/CXXInheritance.h"
#include "plugin.hxx"
namespace {
// cf. Clang's clang::AST::CXXDynamicCastExpr::isAlwaysNull
// (lib/AST/ExprCXX.cpp):
bool isAlwaysNull(CXXDynamicCastExpr const * expr) {
QualType SrcType = expr->getSubExpr()->getType();
QualType DestType = expr->getType();
if (const clang::PointerType *SrcPTy = SrcType->getAs<clang::PointerType>()) {
SrcType = SrcPTy->getPointeeType();
#if 0
DestType = DestType->castAs<PointerType>()->getPointeeType();
#else
auto DstPTy = DestType->getAs<clang::PointerType>();
if (!DstPTy)
return false;
DestType = DstPTy->getPointeeType();
#endif
}
if (DestType->isVoidType())
return false;
#if 0
const CXXRecordDecl *SrcRD =
cast<CXXRecordDecl>(SrcType->castAs<RecordType>()->getDecl());
#else
auto SrcRT = SrcType->getAs<RecordType>();
if (!SrcRT)
return false;
const CXXRecordDecl *SrcRD = cast<CXXRecordDecl>(SrcRT->getDecl());
#endif
#if 0
if (!SrcRD->hasAttr<FinalAttr>())
return false;
#endif
#if 0
const CXXRecordDecl *DestRD =
cast<CXXRecordDecl>(DestType->castAs<RecordType>()->getDecl());
#else
auto DestRT = DestType->getAs<RecordType>();
if (!DestRT)
return false;
const CXXRecordDecl *DestRD = cast<CXXRecordDecl>(DestRT->getDecl());
#endif
#if 1
if (!(SrcRD && DestRD))
return false;
if (DestRD->hasAttr<FinalAttr>()) {
CXXBasePaths Paths(/*FindAmbiguities=*/false, /*RecordPaths=*/true,
/*DetectVirtual=*/false);
if (DestRD->isDerivedFrom(SrcRD, Paths) &&
std::all_of(Paths.begin(), Paths.end(),
[](CXXBasePath const & Path) {
return Path.Access != AS_public; }))
return true;
}
if (!SrcRD->hasAttr<FinalAttr>())
return false;
#endif
#if 0
return !DestRD->isDerivedFrom(SrcRD);
#else
return !(DestRD->isDerivedFrom(SrcRD)
|| SrcRD->isDerivedFrom(DestRD)
|| SrcRD == DestRD);
#endif
}
class FailedDynCast:
public RecursiveASTVisitor<FailedDynCast>, public loplugin::Plugin
{
public:
explicit FailedDynCast(InstantiationData const & data): Plugin(data) {}
bool shouldVisitTemplateInstantiations() const { return true; }
void run() override;
bool VisitCXXDynamicCastExpr(CXXDynamicCastExpr const * expr);
};
void FailedDynCast::run() {
if (compiler.getLangOpts().CPlusPlus) {
TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
}
}
bool FailedDynCast::VisitCXXDynamicCastExpr(CXXDynamicCastExpr const * expr) {
if (ignoreLocation(expr)) {
return true;
}
if (isAlwaysNull(expr)) {
report(
DiagnosticsEngine::Warning,
"dynamic_cast from %0 to %1 always fails", expr->getLocStart())
<< expr->getSubExpr()->getType() << expr->getType()
<< expr->getSourceRange();
}
return true;
}
loplugin::Plugin::Registration<FailedDynCast> X("faileddyncast");
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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