//===-- InvalidatedIteratorChecker.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

//

//===----------------------------------------------------------------------===//

//

// Defines a checker for access of invalidated iterators.

//

//===----------------------------------------------------------------------===//

#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"

#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"

#include "clang/StaticAnalyzer/Core/Checker.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"

#include "Iterator.h"

using namespace clang;

using namespace ento;

using namespace iterator;

namespace {

class InvalidatedIteratorChecker

  : public Checker<check::PreCall, check::PreStmt<UnaryOperator>,

                   check::PreStmt<BinaryOperator>,

                   check::PreStmt<ArraySubscriptExpr>,

                   check::PreStmt<MemberExpr>> {

  std::unique_ptr<BugType> InvalidatedBugType;

  void verifyAccess(CheckerContext &C, const SVal &Val) const;

  void reportBug(const StringRef &Message, const SVal &Val,

                 CheckerContext &C, ExplodedNode *ErrNode) const;

public:

  InvalidatedIteratorChecker();

  void checkPreCall(const CallEvent &Call, CheckerContext &C) const;

  void checkPreStmt(const UnaryOperator *UO, CheckerContext &C) const;

  void checkPreStmt(const BinaryOperator *BO, CheckerContext &C) const;

  void checkPreStmt(const ArraySubscriptExpr *ASE, CheckerContext &C) const;

  void checkPreStmt(const MemberExpr *ME, CheckerContext &C) const;

};

} //namespace

InvalidatedIteratorChecker::InvalidatedIteratorChecker() {

  InvalidatedBugType.reset(

      new BugType(this, "Iterator invalidated", "Misuse of STL APIs"));

}

void InvalidatedIteratorChecker::checkPreCall(const CallEvent &Call,

                                              CheckerContext &C) const {

  // Check for access of invalidated position

  const auto *Func = dyn_cast_or_null<FunctionDecl>(Call.getDecl());

  if (!Func)

    return;

  if (Func->isOverloadedOperator() &&

      
isAccessOperator(Func->getOverloadedOperator())48
) {

    // Check for any kind of access of invalidated iterator positions

    if (const auto *InstCall = dyn_cast<CXXInstanceCall>(&Call)) {

      verifyAccess(C, InstCall->getCXXThisVal());

    } else {

      verifyAccess(C, Call.getArgSVal(0));

    }

  }

}

void InvalidatedIteratorChecker::checkPreStmt(const UnaryOperator *UO,

                                              CheckerContext &C) const {

  if (isa<CXXThisExpr>(UO->getSubExpr()))

    return;

  ProgramStateRef State = C.getState();

  UnaryOperatorKind OK = UO->getOpcode();

  SVal SubVal = State->getSVal(UO->getSubExpr(), C.getLocationContext());

  if (isAccessOperator(OK)) {

    verifyAccess(C, SubVal);

  }

}

void InvalidatedIteratorChecker::checkPreStmt(const BinaryOperator *BO,

                                              CheckerContext &C) const {

  ProgramStateRef State = C.getState();

  BinaryOperatorKind OK = BO->getOpcode();

  SVal LVal = State->getSVal(BO->getLHS(), C.getLocationContext());

  if (isAccessOperator(OK)) {

    verifyAccess(C, LVal);

  }

}

void InvalidatedIteratorChecker::checkPreStmt(const ArraySubscriptExpr *ASE,

                                              CheckerContext &C) const {

  ProgramStateRef State = C.getState();

  SVal LVal = State->getSVal(ASE->getLHS(), C.getLocationContext());

  verifyAccess(C, LVal);

}

void InvalidatedIteratorChecker::checkPreStmt(const MemberExpr *ME,

                                              CheckerContext &C) const {

  if (!ME->isArrow() || 
ME->isImplicitAccess()36
)

    return;

  ProgramStateRef State = C.getState();

  SVal BaseVal = State->getSVal(ME->getBase(), C.getLocationContext());

  verifyAccess(C, BaseVal);

}

void InvalidatedIteratorChecker::verifyAccess(CheckerContext &C, const SVal &Val) const {

  auto State = C.getState();

  const auto *Pos = getIteratorPosition(State, Val);

  if (Pos && 
!Pos->isValid()72
) {

    auto *N = C.generateErrorNode(State);

    if (!N) {

      return;

    }

    reportBug("Invalidated iterator accessed.", Val, C, N);

  }

}

void InvalidatedIteratorChecker::reportBug(const StringRef &Message,

                                           const SVal &Val, CheckerContext &C,

                                           ExplodedNode *ErrNode) const {

  auto R = std::make_unique<PathSensitiveBugReport>(*InvalidatedBugType,

                                                    Message, ErrNode);

  R->markInteresting(Val);

  C.emitReport(std::move(R));

}

void ento::registerInvalidatedIteratorChecker(CheckerManager &mgr) {

  mgr.registerChecker<InvalidatedIteratorChecker>();

}

bool ento::shouldRegisterInvalidatedIteratorChecker(const CheckerManager &mgr) {

  return true;

}