82 lines · cpp
1//=== CXXSelfAssignmentChecker.cpp -----------------------------*- C++ -*--===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8//9// This file defines CXXSelfAssignmentChecker, which tests all custom defined10// copy and move assignment operators for the case of self assignment, thus11// where the parameter refers to the same location where the this pointer12// points to. The checker itself does not do any checks at all, but it13// causes the analyzer to check every copy and move assignment operator twice:14// once for when 'this' aliases with the parameter and once for when it may not.15// It is the task of the other enabled checkers to find the bugs in these two16// different cases.17//18//===----------------------------------------------------------------------===//19 20#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"21#include "clang/StaticAnalyzer/Core/Checker.h"22#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"23 24using namespace clang;25using namespace ento;26 27namespace {28 29class CXXSelfAssignmentChecker : public Checker<check::BeginFunction> {30public:31 CXXSelfAssignmentChecker();32 void checkBeginFunction(CheckerContext &C) const;33};34}35 36CXXSelfAssignmentChecker::CXXSelfAssignmentChecker() {}37 38void CXXSelfAssignmentChecker::checkBeginFunction(CheckerContext &C) const {39 if (!C.inTopFrame())40 return;41 const auto *LCtx = C.getLocationContext();42 const auto *MD = dyn_cast<CXXMethodDecl>(LCtx->getDecl());43 if (!MD)44 return;45 if (!MD->isCopyAssignmentOperator() && !MD->isMoveAssignmentOperator())46 return;47 auto &State = C.getState();48 auto &SVB = C.getSValBuilder();49 auto ThisVal =50 State->getSVal(SVB.getCXXThis(MD, LCtx->getStackFrame()));51 auto Param = SVB.makeLoc(State->getRegion(MD->getParamDecl(0), LCtx));52 auto ParamVal = State->getSVal(Param);53 54 ProgramStateRef SelfAssignState = State->bindLoc(Param, ThisVal, LCtx);55 const NoteTag *SelfAssignTag =56 C.getNoteTag([MD](PathSensitiveBugReport &BR) -> std::string {57 SmallString<256> Msg;58 llvm::raw_svector_ostream Out(Msg);59 Out << "Assuming " << MD->getParamDecl(0)->getName() << " == *this";60 return std::string(Out.str());61 });62 C.addTransition(SelfAssignState, SelfAssignTag);63 64 ProgramStateRef NonSelfAssignState = State->bindLoc(Param, ParamVal, LCtx);65 const NoteTag *NonSelfAssignTag =66 C.getNoteTag([MD](PathSensitiveBugReport &BR) -> std::string {67 SmallString<256> Msg;68 llvm::raw_svector_ostream Out(Msg);69 Out << "Assuming " << MD->getParamDecl(0)->getName() << " != *this";70 return std::string(Out.str());71 });72 C.addTransition(NonSelfAssignState, NonSelfAssignTag);73}74 75void ento::registerCXXSelfAssignmentChecker(CheckerManager &Mgr) {76 Mgr.registerChecker<CXXSelfAssignmentChecker>();77}78 79bool ento::shouldRegisterCXXSelfAssignmentChecker(const CheckerManager &mgr) {80 return true;81}82