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//=== CXXSelfAssignmentChecker.cpp -----------------------------*- 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 CXXSelfAssignmentChecker, which tests all custom defined
// copy and move assignment operators for the case of self assignment, thus
// where the parameter refers to the same location where the this pointer
// points to. The checker itself does not do any checks at all, but it
// causes the analyzer to check every copy and move assignment operator twice:
// once for when 'this' aliases with the parameter and once for when it may not.
// It is the task of the other enabled checkers to find the bugs in these two
// different cases.
//
//===----------------------------------------------------------------------===//
#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
using namespace clang;
using namespace ento;
namespace {
class CXXSelfAssignmentChecker : public Checker<check::BeginFunction> {
public:
CXXSelfAssignmentChecker();
void checkBeginFunction(CheckerContext &C) const;
};
}
CXXSelfAssignmentChecker::CXXSelfAssignmentChecker() {}
void CXXSelfAssignmentChecker::checkBeginFunction(CheckerContext &C) const {
if (!C.inTopFrame())
return;
const auto *LCtx = C.getLocationContext();
const auto *MD = dyn_cast<CXXMethodDecl>(LCtx->getDecl());
if (!MD)
return;
if (!MD->isCopyAssignmentOperator() && !MD->isMoveAssignmentOperator())
return;
auto &State = C.getState();
auto &SVB = C.getSValBuilder();
auto ThisVal =
State->getSVal(SVB.getCXXThis(MD, LCtx->getStackFrame()));
auto Param = SVB.makeLoc(State->getRegion(MD->getParamDecl(0), LCtx));
auto ParamVal = State->getSVal(Param);
ProgramStateRef SelfAssignState = State->bindLoc(Param, ThisVal, LCtx);
const NoteTag *SelfAssignTag =
C.getNoteTag([MD](PathSensitiveBugReport &BR) -> std::string {
SmallString<256> Msg;
llvm::raw_svector_ostream Out(Msg);
Out << "Assuming " << MD->getParamDecl(0)->getName() << " == *this";
return std::string(Out.str());
});
C.addTransition(SelfAssignState, SelfAssignTag);
ProgramStateRef NonSelfAssignState = State->bindLoc(Param, ParamVal, LCtx);
const NoteTag *NonSelfAssignTag =
C.getNoteTag([MD](PathSensitiveBugReport &BR) -> std::string {
SmallString<256> Msg;
llvm::raw_svector_ostream Out(Msg);
Out << "Assuming " << MD->getParamDecl(0)->getName() << " != *this";
return std::string(Out.str());
});
C.addTransition(NonSelfAssignState, NonSelfAssignTag);
}
void ento::registerCXXSelfAssignmentChecker(CheckerManager &Mgr) {
Mgr.registerChecker<CXXSelfAssignmentChecker>();
}
bool ento::shouldRegisterCXXSelfAssignmentChecker(const CheckerManager &mgr) {
return true;
}
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