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// SmartPtrModeling.cpp - Model behavior of C++ smart pointers - C++ ------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines a checker that models various aspects of
// C++ smart pointer behavior.
//
//===----------------------------------------------------------------------===//
#include "Move.h"
#include "clang/AST/ExprCXX.h"
#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "clang/StaticAnalyzer/Core/CheckerManager.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
using namespace clang;
using namespace ento;
namespace {
class SmartPtrModeling : public Checker<eval::Call> {
bool isNullAfterMoveMethod(const CXXInstanceCall *Call) const;
public:
bool evalCall(const CallExpr *CE, CheckerContext &C) const;
};
} // end of anonymous namespace
bool SmartPtrModeling::isNullAfterMoveMethod(
const CXXInstanceCall *Call) const {
// TODO: Update CallDescription to support anonymous calls?
// TODO: Handle other methods, such as .get() or .release().
// But once we do, we'd need a visitor to explain null dereferences
// that are found via such modeling.
const auto *CD = dyn_cast_or_null<CXXConversionDecl>(Call->getDecl());
return CD && CD->getConversionType()->isBooleanType();
}
bool SmartPtrModeling::evalCall(const CallExpr *CE, CheckerContext &C) const {
CallEventRef<> CallRef = C.getStateManager().getCallEventManager().getCall(
CE, C.getState(), C.getLocationContext());
const auto *Call = dyn_cast_or_null<CXXInstanceCall>(CallRef);
if (!Call || !isNullAfterMoveMethod(Call))
return false;
ProgramStateRef State = C.getState();
const MemRegion *ThisR = Call->getCXXThisVal().getAsRegion();
if (!move::isMovedFrom(State, ThisR)) {
// TODO: Model this case as well. At least, avoid invalidation of globals.
return false;
}
// TODO: Add a note to bug reports describing this decision.
C.addTransition(
State->BindExpr(CE, C.getLocationContext(),
C.getSValBuilder().makeZeroVal(CE->getType())));
return true;
}
void ento::registerSmartPtrModeling(CheckerManager &Mgr) {
Mgr.registerChecker<SmartPtrModeling>();
}
bool ento::shouldRegisterSmartPtrModeling(const LangOptions &LO) {
return LO.CPlusPlus;
}
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